tetracycline and Swine-Diseases

Topics: Animals; Antibodies, Bacterial; Cat Diseases; Cats; Cattle; Cattle Diseases; Chlamydia; Chlamydia Infections; Humans; Sheep; Sheep Diseases; Swine; Swine Diseases; Tetracycline

Topics: Animals; Anti-Bacterial Agents; Bacitracin; Chloramphenicol; Penicillins; Streptomycin; Sulfonamides; Swine; Swine Diseases; Tetracycline

To analyse the prevalence, genetic diversity and antimicrobial susceptibility of Campylobacter spp. in northern Spain.. Campylobacter was isolated from 139 samples of broiler meat and faecal dropping of broiler and swine with a prevalence of 35·4, 62 and 42·8%, respectively. Campylobacter jejuni (n = 55) and Campylobacter coli (n = 31) were identified by multiplex-PCR in meat, faeces and human clinical samples while Campylobacter fetus (n = 3) was exclusively detected in the latter. Fingerprinting by flaA-RFLP and PFGE revealed 68 different genotypes from the 89 isolates with a Biodiversity Simpson's index of 0·98. The 86·5% of the isolates were resistant to ciprofloxacin, 85·4% to tetracycline and 49·4% to erythromycin; only three genotypes were susceptible to the three antimicrobial drugs. Multidrug resistance was detected in the 40·7% of the isolates.. Campylobacter remains prevalent in northern Spain with a high biodiversity degree. About 93·3% of the isolates were resistant to one or more drugs.. Although different measures are taken to control Campylobacter, the detection of isolates resistant to the drugs used in the treatment of campylobacteriosis is still high, including different species and genotypes. This evidences the need of additional strategies against this pathogen.

Topics: Animals; Anti-Bacterial Agents; Campylobacter coli; Campylobacter Infections; Campylobacter jejuni; Chickens; Ciprofloxacin; Drug Resistance, Bacterial; Erythromycin; Meat; Microbial Sensitivity Tests; Molecular Typing; Phylogeny; Poultry Diseases; Prevalence; Spain; Swine; Swine Diseases; Tetracycline

The emergence of livestock-associated (LA)-methicillin-resistant

Topics: Abattoirs; Animals; Anti-Bacterial Agents; Chlorides; Farmers; Farms; Methicillin; Methicillin Resistance; Methicillin-Resistant Staphylococcus aureus; Multilocus Sequence Typing; Prevalence; Republic of Korea; Staphylococcal Infections; Swine; Swine Diseases; Tetracycline; Zinc Compounds

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) of lineage CC398 is an emerging clone causing human infections but is mostly found in pigs. The aim of this study was to characterize the antimicrobial resistance phenotypes/genotypes of a collection of 137 MRSA CC398 isolates obtained in a previous study from 17 Spanish hospitals, using tetracycline resistance as marker for selection. A multidrug-resistant (MDR) phenotype was present in 79% of analysed isolates, with 17% of them resistant to at least six different antimicrobial families. All tetracycline-resistant isolates (n=137) carried the tetM gene and 75% also carried the tetK gene. Almost 50% of MRSA CC398 isolates showed macrolide and/or lincosamide resistance: a) 39% of isolates were ERY

Topics: Aminoglycosides; Animals; Anti-Bacterial Agents; Antiporters; Drug Resistance, Multiple, Bacterial; Humans; Interspersed Repetitive Sequences; Lincosamides; Macrolides; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Spain; Staphylococcal Infections; Swine; Swine Diseases; Tetracycline; Tetracycline Resistance

Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Bacterial; Enterococcus faecium; Gram-Positive Bacterial Infections; Italy; Microbial Sensitivity Tests; Oxazolidinones; Swine; Swine Diseases; Tetracycline

Antimicrobial helper-compounds may reverse antimicrobial resistance. Sertraline, a antidepressant drug, has been suggested as a tetracycline helper-compound. Tetracycline is the preferred antimicrobial for treatment of enteric diseases in pigs. This study is the first to evaluate the potency of sertraline as a tetracycline adjuvant in pigs.. Forty-eight nursery pigs were divided into four treatment groups: Tetracycline, sertraline, tetracycline/sertraline or un-medicated control. Fecal and ileal samples were obtained before treatment, 48 h and nine days after five days of treatment, respectively. Colony forming units (CFU) of tetracycline resistant coliforms in each sample (ileal or fecal) and CFU of an orally inoculated tetracycline-resistant strain of Escherichia coli were determined at each sampling point. The microbiome of fecal and ileal and samples was analyzed by sequencing of the 16S V3-V4 region.. The results did not provide evidence that sertraline in combination with tetracycline has any impact on tetracycline resistant bacteria in either fecal or ileum samples, while in the tetracycline treated group of pigs, an increase in the prevalence of a tetracycline resistant indicator strain of Escherichia coli shortly after ended five-day treatment was observed. The ileal samples obtained shortly after ended treatment showed treatment-associated changes in the composition of the microbiota in the groups of pigs treated with tetracycline (+/-) sertraline. While tetracycline treatment increased the abundance in the reads of E. coli, sertraline/tetracycline treatment led to increased abundances of Streptococcus spp. and decreased abundances of Lactobacillus spp. However, all observed differences (on CFU counts and microbiota composition) between groups shortly after treatment had diminished in less than two weeks after last treatment day.. Sertraline (+/-) tetracycline treatment did not reduce the long-term level of tetracycline-resistant bacteria in the feces or small intestine contents of piglets compared to the un-medicated control group of pigs. The result of this study reflects the importance of in vivo studies for confirmation of the antimicrobial helper-compound potential of an in vitro active compound.

Topics: Animals; Anti-Bacterial Agents; Biodiversity; Drug Resistance, Multiple, Bacterial; Drug Synergism; Escherichia coli; Escherichia coli Infections; Feces; Microbial Sensitivity Tests; Microbiota; Sertraline; Stem Cells; Swine; Swine Diseases; Tetracycline

Colonization by livestock-associated MRSA (LA-MRSA) has increasingly been reported in the swine population worldwide. The aim of this study was to assess the prevalence of MRSA nasal carriage in healthy pigs, including the black (Calabrese) breed, from farms in the Calabria Region (Southern Italy). Between January and March 2018, a total of 475 healthy pigs reared in 32 farms were sampled by nasal swabbing. MRSA isolates were characterized by spa, MLST and SCCmec typing, and susceptibility testing to 17 antimicrobials.. 22 of 32 (66.8%) pig farms resulted positive for MRSA. The prevalence of MRSA was 46.1% (219 MRSA culture-positive out of 475 samples). MRSA colonization was significantly higher in intensive farms and in pigs with a recent or ongoing antimicrobial treatment. All 219 MRSA isolates were assigned to ST398. The most common spa types were t011 (37.0%), t034 (22.4%) and t899 (15.1%). A novel spa type (t18290) was detected in one isolate. An insertion of IS256 in the ST398-specific A07 fragment of the SAPIG2195 gene was detected in 10 out of 81 t011 isolates. Nearly all isolates carried the SCCmec type V element, except 11 isolates that carried the SCCmec type IVc. None of the isolates was positive for the Panton-Valentine leukocidin. All isolates were resistant to tetracycline. High resistance rates were also found for clindamycin (93.1%), trimethoprim/sulfamethoxazole (68.4%), fluoroquinolones (47.9-65.3%) and erythromycin (46.1%). None of the isolates was resistant to vancomycin and fusidic acid. Overall, a multidrug resistant phenotype was observed in 88.6% of isolates.. We report a high prevalence of MRSA among healthy swine in Southern Italy farms, with higher isolation frequency associated with intensive farming. The epidemiological types identified in our study reflect those reported in other European countries. Our findings underscore the importance of monitoring the evolution of LA-MRSA in pig farms in order to implement control measures and reduce the risk of spread in the animal population.

Topics: Animals; Anti-Bacterial Agents; Bacterial Typing Techniques; Carrier State; Cross-Sectional Studies; DNA, Bacterial; Drug Resistance, Bacterial; Farms; Italy; Livestock; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Multilocus Sequence Typing; Nose; Prevalence; Staphylococcal Infections; Swine; Swine Diseases; Tetracycline

The increasing clinical importance of human infections (frequently severe) caused by

Topics: Animal Husbandry; Animals; Anti-Bacterial Agents; Clostridioides difficile; Clostridium Infections; Evolution, Molecular; Genotype; Molecular Epidemiology; Polymerase Chain Reaction; Ribotyping; Selection, Genetic; Swine; Swine Diseases; Tetracycline

Pasteurella multocida causes single or complex respiratory disease in pigs. Although antimicrobial therapy is the most effective treatment for porcine respiratory disease, P. multocida shows increased antimicrobial resistance in Korea. Therefore, we aimed to investigate the phenotypic and genotypic characterization of tetracycline-resistant P. multocida. Thirty-seven of 454 P. multocida isolates from South Korea between 2010 and 2016 were selected. Four tet genes [tet(B) (78.4%), tet(H) (16.2%), tet(C) (5.4%), and tet(O) (2.7%)] were observed. This is the first report of tet(C) in P. multocida. Various virulence factors were observed in both tetracycline-resistant and -susceptible P. multocida isolates. Genes encoding pmHAS and pfhA were more prevalent in tetracycline-resistant than in tetracycline-susceptible isolates. Some virulence factors exhibited association with serogroups. tadD and sodA were common in serogroup A, while hsf-l was significantly associated with serogroup D (p < 0.01). Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) results showed the genetic diversity of tetracycline-resistant P. multocida. MLST showed six different sequence types (ST), with clonal complex 13 encompassing 56.8% of the strains. PFGE was more efficient in differentiating the isolates, and 29 PFGE patterns of the strains were observed. By combining these methods, identical STs and PFGE patterns were observed in isolates from different farms, suggesting that transmission of antimicrobial-resistant P. multocida strains between farms might occur in a geographically discrete population. In future, epidemiological approaches and development of effective vaccines should focus on the major clonal lineages carrying the important virulence factors and frequently observed resistance genes to prevent the transmission and control the disease.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Bacterial Typing Techniques; Drug Resistance, Bacterial; Electrophoresis, Gel, Pulsed-Field; Genetic Variation; Microbial Sensitivity Tests; Multilocus Sequence Typing; Pasteurella multocida; Phenotype; Repressor Proteins; Republic of Korea; Serogroup; Swine; Swine Diseases; Tetracycline; Virulence Factors

The collaboration project VASIB aims at reducing the antibiotic consumption in pig production by integrating information from consulting expertise in clinical inspection, hygiene, epidemiology, microbiology and pharmacology. In this VASIB subproject, we investigated the antimicrobial susceptibility and relatedness of porcine respiratory tract pathogens. Bordetella bronchiseptica (n = 47), Pasteurella multocida (n = 18) and Streptococcus suis (n = 58) were obtained from weaner pigs at two farms. Antimicrobial susceptibility testing was performed by broth microdilution according to CLSI standards. Resistance genes were detected via specific PCR assays. Macrorestriction analysis was conducted to determine the relatedness of the isolates and to identify clones. The B. bronchiseptica isolates showed indistinguishable (farm 1) or two closely related XbaI-patterns (farm 2). Different SmaI-PFGE patterns of P. multocida isolates were obtained at three different time points. In contrast, PFGE analysis of S. suis indicated more than one fragment pattern per pig and time point. Isolates exhibiting indistinguishable PFGE patterns were considered to represent the same clone. This study showed that only two closely related B. bronchiseptica clones were present in both farms, which had low MICs to all antimicrobials, except to β-lactams. Different P. multocida clones were present at the three time points. They showed overall low MIC values, with two clones being resistant and one intermediate to tetracycline. S. suis clones were resistant to tetracycline (n = 19) and/or erythromycin/clindamycin (n = 16). They harboured the tetracycline resistance genes tet(O), tet(M) or tet(L) and/or the macrolide/lincosamide/streptogramin B resistance gene erm(B). Five penicillin-resistant S. suis clones were also detected.

Topics: Animals; Anti-Infective Agents; Bacteria; beta-Lactams; Bordetella bronchiseptica; Bordetella Infections; Drug Resistance, Multiple, Bacterial; Lincosamides; Macrolides; Microbial Sensitivity Tests; Pasteurella Infections; Pasteurella multocida; Respiratory Tract Infections; Streptococcal Infections; Streptococcus suis; Swine; Swine Diseases; Tetracycline; Weaning

Streptococcus suis is a major zoonotic pathogen that causes severe disease in both humans and pigs. Australia's pig herd has been quarantined for over 30 years, however S. suis remains a significant cause of disease. In this study, we investigated S. suis from 148 cases of clinical disease in pigs from 46 pig herds over a period of seven years, to determine the level of genetic difference from international isolates that may have arisen over the 30 years of separation. Isolates underwent whole genome sequencing, genome analysis and antimicrobial susceptibility testing. Data was compared at the core genome level to clinical isolates from overseas. Results demonstrated five predominant multi-locus sequence types and two major cps gene types (cps2 and 3). At the core genome level Australian isolates clustered predominantly within one large clade consisting of isolates from the UK, Canada and North America. A small proportion of Australian swine isolates (5%) were phylogenetically associated with south-east Asian and UK isolates, many of which were classified as causing systemic disease, and derived from cases of human and swine disease. Based on this dataset we provide a comprehensive outline of the current S. suis clones associated with disease in Australian pigs and their global context, with the main finding being that, despite three decades of separation, Australian S. suis are genomically similar to overseas strains. In addition, we show that ST1 clones carry a constellation of putative virulence genes not present in other Australian STs.

Topics: Animals; Anti-Bacterial Agents; Australia; Drug Resistance, Multiple, Bacterial; Erythromycin; Genome, Bacterial; Genomics; Humans; Multilocus Sequence Typing; Phylogeny; Streptococcal Infections; Streptococcus suis; Swine; Swine Diseases; Tetracycline; Viral Proteins; Virulence; Virulence Factors

The spread of livestock-associated methicillin-resistant

Topics: Animals; Anti-Bacterial Agents; Denmark; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Farms; Genome, Bacterial; Humans; Livestock; Methicillin-Resistant Staphylococcus aureus; Prevalence; Staphylococcal Infections; Swine; Swine Diseases; Tetracycline; Whole Genome Sequencing; Zoonoses

The antimicrobial resistance of Salmonella strains is rapidly increasing worldwide, which poses significant threats to animal and public health. In this study, a total of 249 porcine Salmonella isolates collected in China during 2008-2015 were examined, including 155 clinical isolates from diseased pigs and 94 nonclinical isolates from healthy pigs. Based on the minimum inhibitory concentration of seven antimicrobial agents, 96.4% of the isolates were resistant to at least one of the tested antibiotics and 81.0% of them showed multidrug resistance. The highest antimicrobial resistance was observed for tetracycline (85.9%), and the lowest was found for cefotaxime (13.3%). The isolates from diseased pigs exhibited significantly higher levels of antimicrobial resistance than those from healthy pigs. Twenty-two isolates from healthy pigs were resistant to ciprofloxacin, which may inhibit the curative effectiveness of fluoroquinolones on bacterial food-borne poisoning and infections in humans caused by contaminated food. Moreover, cefotaxime resistance of the strains isolated from diseased pigs during 2013-2015 was significantly higher compared with the strains isolated during 2008-2010. Further study showed that the correlation between phenotypic and genotypic resistance varied among the isolates from different sources, and in many cases, the presence of resistance genes was not consistent with the resistance to the corresponding antimicrobials. These results are very significant for veterinary practice and public health.

Topics: Animal Husbandry; Animals; Anti-Bacterial Agents; Cefotaxime; China; Ciprofloxacin; Drug Resistance, Multiple, Bacterial; Farms; Genotype; Phenotype; Salmonella; Salmonella Infections, Animal; Serogroup; Swine; Swine Diseases; Tetracycline

Antimicrobial use and resistance in animal and food production are of concern to public health. The primary aims of this study were to determine the frequency of resistance to 12 antimicrobials in Escherichia coli isolates from 39 pig farms and to identify patterns of antimicrobial use on these farms. Further aims were to determine whether a categorization of farms based on the duration of in-feed antimicrobial use (long-term versus short-term) could predict the occurrence of resistance on these farms and to identify the usage of specific antimicrobial drugs associated with the occurrence of resistance. Escherichia coli were isolated from all production stages on these farms; susceptibility testing was carried out against a panel of antimicrobials. Antimicrobial prescribing data were collected, and farms were categorized as long term or short term based on these. Resistance frequencies and antimicrobial use were tabulated. Logistic regression models of resistance to each antimicrobial were constructed with stage of production, duration of antimicrobial use and the use of 5 antimicrobial classes included as explanatory variables in each model. The greatest frequencies of resistance were observed to tetracycline, trimethoprim/sulphamethoxazole and streptomycin with the highest levels of resistance observed in isolates from first-stage weaned pigs. Differences in the types of antimicrobial drugs used were noted between long-term and short-term use farms. Categorization of farms as long- or short-term use was sufficient to predict the likely occurrence of resistance to 3 antimicrobial classes and could provide an aid in the control of resistance in the food chain. Stage of production was a significant predictor variable in all models of resistance constructed and did not solely reflect antimicrobial use at each stage. Cross-selection and co-selection for resistance was evident in the models constructed, and the use of trimethoprim/sulphonamide drugs in particular was associated with the occurrence of resistance to other antimicrobials.

Topics: Animal Feed; Animal Husbandry; Animals; Anti-Infective Agents; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Infections; Feces; Logistic Models; Streptomycin; Sulfamethoxazole; Swine; Swine Diseases; Tetracycline; Trimethoprim

In 2013-2014, 201 pigs belonging to 67 batches were tested for Salmonella in their mesenteric lymph nodes (MLN) in one abattoir of Northern Italy. For each batch, faecal material was collected at lairage by swabbing the pen floor for approximately 1600 cm(2). The aim of this study was to investigate the prevalence of Salmonella in MLN of pigs at slaughter, to assess Salmonella contamination at lairage and to evaluate the effect of lairage duration on its prevalence. Serotyping, XbaI PFGE typing and antimicrobial testing of the isolates were performed. Pig and human Salmonella isolates of the same region of Italy were compared to evaluate possible correlations. Salmonella enterica was isolated from 19.9% of the MLN and 49.3% of the environmental faecal samples. Nine different serovars were identified among 75 S. enterica isolates. In MLN Salmonella Derby was the most common (52.5%), followed by S. enterica 4,[5],12:i:- (17.5%) and Salmonella Rissen (10.0%). In faecal samples S. Derby was prevalent (51.4%), followed by S. enterica 4,[5], 12:i:- (20.0%) and Salmonella Brandenburg (14.3%). Lairage holding varied between 1 and ≥ 12 h (median value: 2.5h). In pigs held for 1-3h, 14.1% were positive for Salmonella in MLN but the prevalence reached 31.8% when they were held for ≥ 12 h. The contamination of MLN was statistically different (p=0.0045) between the two groups, thus confirming the role of long-lasting lairage in Salmonella contamination of pigs. XbaI PFGE typing detected 36 PFGE types. Twenty-three PFGE types were identified among the 40 MLN isolates and 22 PFGE types among the 35 faecal isolates. A total of 11 PFGE types were shared between the MLN of pigs and the lairage environment. Among S. Derby, 6 shared PFGE types between MLN and faeces were found and among S. enterica 4,[5],12:i:- one PFGE type was common between MLN and the faecal samples. Shared profiles between human and swine isolates of S. Derby, S. enterica 4,[5],12:i:-, S. Rissen, Salmonella Manhattan, S. Brandenburg, Salmonella Livingstone, Salmonella London and Salmonella Muenchen were identified. Among S. Derby and S. enterica 4,[5],12:i:- isolates found in pigs, 6/15 profiles (40.0%) and 8/10 (80.0%) were shared with human isolates. High resistance rates to streptomycin (97.3%), sulphonamide compounds (84.0%) and tetracycline (56.0%) were observed. No resistance was detected to ertapenem and meropenem. High proportions of isolates showed intermediate sensitivity to ciprofloxacin (85.

Topics: Abattoirs; Animals; Anti-Bacterial Agents; Drug Resistance, Bacterial; Electrophoresis, Gel, Pulsed-Field; Feces; Humans; Italy; Lymph Nodes; Meat; Microbial Sensitivity Tests; Prevalence; Salmonella enterica; Salmonella Infections, Animal; Serotyping; Swine; Swine Diseases; Tetracycline

The aims of the present study were to assess the prevalence of Chlamydia suis in an Italian pig herd, determine the tetracycline susceptibility of C. suis isolates, and evaluate tet(C) and tetR(C) gene expression. Conjunctival swabs from 20 pigs were tested for C. suis by real-time polymerase chain reaction, and 55% (11) were positive. C. suis was then isolated from 11 conjunctival swabs resampled from the same herd. All positive samples and isolates were positive for the tet(C) resistance gene. The in vitro susceptibility to tetracycline of the C. suis isolates showed MIC values ranging from 0.5 to 4 μg/mL. Tet(C) and tetR(C) transcripts were found in all the isolates, cultured both in the absence and presence of tetracycline. This contrasts with other Gram-negative bacteria in which both genes are repressed in the absence of the drug. Further investigation into tet gene regulation in C. suis is needed.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Chlamydia; Chlamydia Infections; DNA, Bacterial; Italy; Microbial Sensitivity Tests; Real-Time Polymerase Chain Reaction; Repressor Proteins; RNA, Ribosomal, 23S; Swine; Swine Diseases; Tetracycline; Tetracycline Resistance

Land application of swine manure in commercial hog farms is an integral part of their waste management system which recycles the nutrients back to the soil. However, manure application can lead to the dissemination of bacterial pathogens in the environment and pose a serious public health threat. The aim of this study was to determine the dissemination of antimicrobial resistant Salmonella in the environment due to manure application in commercial swine farms in North Carolina (n = 6) and Iowa (n = 7), two leading pork producing states in the US. We collected manure and soil samples twice on day 0 (before and after manure application) from four distinct plots of lands (5 soil samples/plot) located at 20 feet away from each other in the field. Subsequent soil samples were collected again on days 7, 14, 21 from the same plots. A total of 1,300 soil samples (NC = 600; IA = 700) and 130 manure samples (NC = 60; IA = 70) were collected and analyzed in this study. The overall Salmonella prevalence was 13.22% (189/1,430), represented by 10.69% and 38.46% prevalence in soil and manure, respectively. The prevalence in NC (25.45%) was significantly higher than in IA (2.73%) (P<0.001) and a consistent decrease in Salmonella prevalence was detected from Day 0-Day 21 in all the farms that tested positive. Salmonella serotypes detected in NC were not detected in IA, thereby highlighting serotype association based on manure storage and soil application method used in the two regions. Antimicrobial susceptibility testing was done by the broth microdilution method to a panel of 15 antimicrobial drugs. A high frequency of isolates (58.73%) were multidrug resistant (resistance to three or more class of antimicrobials) and the most frequent resistance was detected against streptomycin (88.36%), sulfisoxazole (67.2%), and tetracycline (57.67%). Genotypic characterization by pulse field gel electrophoresis revealed clonally related Salmonella in both manure and soil at multiple time points in the positive farms. Our study highlights the potential role of swine manure application in the dissemination and persistence of antimicrobial resistant Salmonella in the environment.

Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Electrophoresis, Gel, Pulsed-Field; Environment; Manure; Microbial Sensitivity Tests; Phylogeny; Salmonella; Salmonella Infections, Animal; Serogroup; Streptomycin; Sulfisoxazole; Swine; Swine Diseases; Tetracycline

In pigs, Chlamydia suis has been associated with respiratory disease, diarrhea and conjunctivitis, but there is a high rate of inapparent C. suis infection found in the gastrointestinal tract of pigs. Tetracycline resistance in C. suis has been described in the USA, Italy, Switzerland, Belgium, Cyprus and Israel. Tetracyclines are commonly used in pig production due to their broad-spectrum activity and relatively low cost. The aim of this study was to isolate clinical C. suis samples in cell culture and to evaluate their antibiotic susceptibility in vitro under consideration of antibiotic treatment on herd level. Swab samples (n = 158) identified as C. suis originating from 24 farms were further processed for isolation, which was successful in 71% of attempts with a significantly higher success rate from fecal swabs compared to conjunctival swabs. The farms were divided into three treatment groups: A) farms without antibiotic treatment, B) farms with prophylactic oral antibiotic treatment of the whole herd consisting of trimethoprime, sulfadimidin and sulfathiazole (TSS), or C) farms giving herd treatment with chlortetracycline with or without tylosin and sulfadimidin (CTS). 59 isolates and their corresponding clinical samples were selected and tested for the presence or absence of the tetracycline resistance class C gene [tet(C)] by conventional PCR and isolates were further investigated for their antibiotic susceptibility in vitro. The phenotype of the investigated isolates was either classified as tetracycline sensitive (Minimum inhibitory concentration [MIC] < 2 μg/ml), intermediate (2 μg/ml ≤ MIC < 4 μg/ml) or resistant (MIC ≥ 4 μg/ml). Results of groups and individual pigs were correlated with antibiotic treatment and time of sampling (beginning/end of the fattening period). We found clear evidence for selective pressure as absence of antibiotics led to isolation of only tetracycline sensitive or intermediate strains whereas tetracycline treatment resulted in a greater number of tetracycline resistant isolates.

Topics: Administration, Oral; Animals; Bacterial Load; Bacterial Proteins; Chlamydia; Chlamydia Infections; False Negative Reactions; Farms; Microbial Sensitivity Tests; Polymerase Chain Reaction; Repressor Proteins; Selection, Genetic; Sus scrofa; Swine; Swine Diseases; Switzerland; Tetracycline; Tetracycline Resistance

A livestock-associated clonal lineage (ST398) of methicillin-resistant Staphylococcus aureus (MRSA) has been identified causing colonization or infection in farm workers. The aim of the study was to analyze the prevalence of MRSA-ST398 colonization in pigs and in pig farmers in an area with a high pig population (Osona, Barcelona province, Catalonia, Spain).. We performed a cross-sectional prevalence study in Osona (Catalonia, Spain), from June 2014 to June 2015. All pig farm workers from 83 farms were studied. Twenty of these farms were randomly selected for the study of both pigs and farmers: 9 fattening and 11 farrow-to-finish farms. All workers over the age of 18 who agreed to participate were included. Samples were analyzed to identify MRSA-ST398 and their spa type.. Eighty-one of the 140 pig farm workers analyzed (57.9% (95% IC: 50.0-66.4%)) were MRSA-positive, all of them ST398. The mean number of years worked on farms was 17.5 ± 12.6 (range:1-50), without significant differences between positive and negative MRSA results (p = 0.763). Over 75% of MRSA-ST398 carriers worked on farms with more than 1250 pigs (p < 0.001). At least one worker tested positive for MRSA-ST398 on all 20 selected pig farms. Ninety-two (46.0% (95% IC: 39.0-53.0%)) of the nasal swabs from 200 pigs from these 20 farms were MRSA-positive, with 50.5% of sows and 41.4% of fattening pigs (p = 0.198) giving MRSA-positive results. All the isolates were tetracycline-resistant, and were identified as MRSA-ST398. The spa type identified most frequently was t011 (62%). Similar spa types and phenotypes of antibiotic resistance were identified in pigs and farmers of 19/20 tested farms.. The prevalence of MRSA-ST398 among pig farm workers and pigs on farms in the studied region is very high, and the size of the farm seems to correlate with the frequency of colonization of farmers. The similar spa-types and phenotypes of resistance detected in pigs and workers in most of the farms studied suggest animal-to-human transmission.

Topics: Adult; Animals; Anti-Bacterial Agents; Carrier State; Cross-Sectional Studies; Farmers; Farms; Female; Humans; Livestock; Male; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Middle Aged; Nasal Mucosa; Occupational Diseases; Prevalence; Spain; Staphylococcal Infections; Sus scrofa; Swine; Swine Diseases; Tetracycline; Tetracycline Resistance

IncA/C plasmids are broad-host-range plasmids enabling multidrug resistance that have emerged worldwide among bacterial pathogens of humans and animals. Although antibiotic usage is suspected to be a driving force in the emergence of such strains, few studies have examined the impact of different types of antibiotic administration on the selection of plasmid-containing multidrug resistant isolates. In this study, chlortetracycline treatment at different concentrations in pig feed was examined for its impact on selection and dissemination of an IncA/C plasmid introduced orally via a commensal Escherichia coli host. Continuous low-dose administration of chlortetracycline at 50 g per ton had no observable impact on the proportions of IncA/C plasmid-containing E. coli from pig feces over the course of 35 days. In contrast, high-dose administration of chlortetracycline at 350 g per ton significantly increased IncA/C plasmid-containing E. coli in pig feces (P < 0.001) and increased movement of the IncA/C plasmid to other indigenous E. coli hosts. There was no evidence of conjugal transfer of the IncA/C plasmid to bacterial species other than E. coli. In vitro competition assays demonstrated that bacterial host background substantially impacted the cost of IncA/C plasmid carriage in E. coli and Salmonella. In vitro transfer and selection experiments demonstrated that tetracycline at 32 μg/ml was necessary to enhance IncA/C plasmid conjugative transfer, while subinhibitory concentrations of tetracycline in vitro strongly selected for IncA/C plasmid-containing E. coli. Together, these experiments improve our knowledge on the impact of differing concentrations of tetracycline on the selection of IncA/C-type plasmids.

Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Infections; Gene Transfer, Horizontal; Plasmids; Swine; Swine Diseases; Tetracycline

In Escherichia coli the genes involved in the acquisition of tetracycline resistance are mainly tet(A) and tet(B). In addition, tet(M) is the most common tetracycline resistance determinant in enterococci and it is associated with conjugative transposons and plasmids. Although tet(M) has been identified in E. coli, to our knowledge, there are no previous reports studying the linkage of the tet(M) gene in E. coli to different mobile genetic elements. The aim of this study was to determine the occurrence of tet(A), tet(B), and tet(M) genes in doxycycline-resistant E. coli isolates from pigs, as well as the detection of mobile genetic elements linked to tet(M) in E. coli and its possible transfer from enterococci.. tet(A) was the most frequently detected gene (87.9%) in doxycycline-resistant isolates. tet(M) was found in 13.1% E. coli isolates. The tet(M) gene was detected in relation with conjugative transposons in 10 out of 36 enterococci isolates analyzed but not in any of E. coli isolates positive for tet(M). Southern blot showed that in E. coli and in most of the enterococci isolates the tet(M) gene was carried on a plasmid. According to the phylogenetic analysis, E. coli contained a new tet(M) allele grouping separately. Mating experiments revealed that tet(M) was carried on a mobile element successfully transferred between enterococci and between enterococci and E. coli.. The detection of tet(M) in E. coli isolates from pigs was higher than expected. In our study, tet(M) detected in E. coli seems not to have been transferred from enterococci, although it can not be ruled out that the horizontal transfer of this gene occurred from other intestinal tract bacteria.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Infections; Gene Expression Regulation, Bacterial; Genetic Linkage; Interspersed Repetitive Sequences; Swine; Swine Diseases; Tetracycline

Topics: Animals; Anti-Bacterial Agents; Methicillin-Resistant Staphylococcus aureus; Nasal Cavity; Swine Diseases; Tetracycline; Zinc

Topics: Animals; Anti-Bacterial Agents; Methicillin-Resistant Staphylococcus aureus; Nasal Cavity; Swine Diseases; Tetracycline; Zinc

On a piglet producing farm severe lameness was observed in pigs which had been weaned 3 weeks and longer due to severe distortions of joints and claws of fore and/or hind legs. Splaying of claws as well as flexural limb deformations particularly in the carpal joints increased in degree the older and heavier the pigs were. Because of coughing in the weaners, which had started 7-8 weeks before any lameness or limb deformation had been apparent, tetracycline was applied via water as medication. During the course of an on-site investigation, a miscalculation of dosage - 129-168 mg tetracycline per kg body weight - was revealed. It was therefore suggested to the farmer and his veterinarian to immediately stop the application of tetracycline and to use a different antibiotic against the still present coughing and sneezing. During a follow-up evaluation 4 weeks later, the farmer reported a significant decrease in affected animals. While a direct correlation between the lameness in the weaned pigs and the tetracycline dosage could not be proven, the existing evidence supports the theory that the overdosage was at least a contributing factor.

Topics: Animals; Hoof and Claw; Lameness, Animal; Sus scrofa; Swine; Swine Diseases; Tetracycline; Weaning

Streptococcus suis serotype 2 is known to cause severe infections in pigs, including meningitis, endocarditis and pneumonia. Furthermore, this bacterium is considered an emerging zoonotic agent. Recently, increased antibiotic resistance in S. suis has been reported worldwide. The objective of this study was to evaluate the potential of nisin, a bacteriocin of the lantibiotic class, as an antibacterial agent against the pathogen S. suis serotype 2. In addition, the synergistic activity of nisin in combination with conventional antibiotics was assessed. Using a plate assay, the nisin-producing strain Lactococcus lactis ATCC 11454 proved to be capable of inhibiting the growth of S. suis (n=18) belonging to either sequence type (ST)1, ST25, or ST28. In a microdilution broth assay, the minimum inhibitory concentration (MIC) of purified nisin ranged between 1.25 and 5 μg/mL while the minimum bactericidal concentration (MBC) was between 5 and 10 μg/mL toward S. suis. The use of a capsule-deficient mutant of S. suis indicated that the presence of this polysaccharidic structure has no marked impact on susceptibility to nisin. Following treatment of S. suis with nisin, transmission electron microscopy observations revealed lysis of bacteria resulting from breakdown of the cell membrane. A time-killing curve showed a rapid bactericidal activity of nisin. Lastly, synergistic effects of nisin were observed in combination with several antibiotics, including penicillin, amoxicillin, tetracycline, streptomycin and ceftiofur. This study brought clear evidence supporting the potential of nisin for the prevention and treatment of S. suis infections in pigs.

Topics: Amoxicillin; Animals; Anti-Bacterial Agents; Bacterial Capsules; Bacterial Typing Techniques; Cell Membrane; Cephalosporins; Drug Combinations; Drug Resistance, Microbial; Drug Synergism; Lactococcus lactis; Microbial Sensitivity Tests; Microscopy, Electron, Transmission; Nisin; Penicillins; Streptococcal Infections; Streptococcus suis; Streptomycin; Swine; Swine Diseases; Tetracycline

The objective of this work was to retrospectively assess records received through the Ontario Swine Veterinary-based Surveillance program July 2007 - July 2009 to describe and assess relationships between reported treatment failure, antimicrobial use, diagnosis and body system affected.. Antimicrobial use occurred in 676 records, 80.4% of all records recording treatment (840). The most commonly used antimicrobials were penicillin (34.9%), tetracyclines (10.7%) and ceftiofur (7.8%), and the use of multiple antimicrobials occurred in 141/676 records (20.9%). A multi-level logistic regression model was built to describe the probability of reported treatment failure. The odds of reported treatment failure were significantly reduced if the record indicated that the gastro-intestinal (GI) system was affected, as compared to all other body systems (p < 0.05). In contrast, the odds of reported treatment failure increased by 1.98 times if two antimicrobials were used as compared to one antimicrobial (p = 0.009) and by 6.52 times if three or more antimicrobials were used as compared to one antimicrobial (p = 0.005). No significant increase in reported treatment failure was seen between the use of two antimicrobials and three or more antimicrobials. No other antimicrobials were significantly associated with reported treatment failure after controlling for body system and the number of antimicrobials used.. Failure of antimicrobial treatment is more likely to occur in non-GI conditions, as compared to GI conditions and the use of multiple antimicrobial products is also associated with an increased probability of antimicrobial treatment failure. The authors suggest that a more preventative approach to herd health should be taken in order to reduce antimicrobial inputs on-farm, including improved immunity via vaccination, management and biosecurity strategies. Furthermore, improved immunity may be viewed as a form of antimicrobial stewardship to the industry by reducing required antimicrobial inputs and consequently, reduced selection pressure for AMR.

Topics: Animals; Anti-Infective Agents; Cephalosporins; Ontario; Penicillins; Population Surveillance; Retrospective Studies; Swine; Swine Diseases; Tetracycline; Treatment Failure; Treatment Outcome; Veterinary Medicine

Similar cases of severe reproductive failure associated with the presence of Chlamydia suis in two Belgian, one Cypriote and one Israeli pig farrowing to slaughter farms are presented. Vaginal and rectal swabs from 39 sows were examined by culture and DNA microarray. Nineteen of 23 (83 %) C. suis-positive sows were infected with tetracycline-resistant C. suis strains, as determined by MIC tests. Furthermore, boar semen from a German artificial insemination centre, intended for export, was positive for C. suis. Emergence of tetracycline-resistant C. suis strains was confirmed.

Topics: Animals; Animals, Domestic; Anti-Bacterial Agents; Belgium; Chlamydia; Chlamydia Infections; Cyprus; DNA, Bacterial; Insemination, Artificial; Israel; Microbial Sensitivity Tests; Reproduction; Swine; Swine Diseases; Tetracycline; Tetracycline Resistance

In this study the plasmid pTC, a 90 kb self-conjugative virulence plasmid of the porcine enterotoxigenic Escherichia coli (ETEC) strain EC2173 encoding the STa and STb heat-stable enterotoxins and tetracycline resistance, has been sequenced in two steps. As a result we identified five main distinct regions of pTC: (i) the maintenance region responsible for the extreme stability of the plasmid, (ii) the TSL (toxin-specific locus comprising the estA and estB genes) which is unique and characteristic for pTC, (iii) a Tn10 transposon, encoding tetracycline resistance, (iv) the tra (plasmid transfer) region, and (v) the colE1-like origin of replication. It is concluded that pTC is a self-transmissible composite plasmid harbouring antibiotic resistance and virulence genes. pTC belongs to a group of large conjugative E. coli plasmids represented by NR1 with a widespread tra backbone which might have evolved from a common ancestor. This is the first report of a completely sequenced animal ETEC virulence plasmid containing an antimicrobial resistance locus, thereby representing a selection advantage for spread of pathogenicity in the presence of antimicrobials leading to increased disease potential.

Topics: Animals; Anti-Bacterial Agents; Bacterial Toxins; Base Sequence; DNA, Bacterial; Enterotoxigenic Escherichia coli; Enterotoxins; Escherichia coli Infections; Escherichia coli Proteins; Genetic Loci; Humans; Molecular Sequence Annotation; Molecular Sequence Data; Plasmids; Sequence Analysis, DNA; Swine; Swine Diseases; Tetracycline; Tetracycline Resistance; Virulence; Virulence Factors

The in vitro activity of mastoparan-AF, an amphipathic antimicrobial peptide isolated from the hornet venom of Vespa affinis, alone and in combination with various clinically used antibiotics, was investigated against 21 Escherichia coli isolates/strains. Most E. coli isolates tested were detected containing multiple-antimicrobial resistance genes. Antimicrobial activity of mastoparan-AF was measured by MIC, MBC, time-kill kinetic assay and chequerboard titration method. Mastoparan-AF exhibited potent antimicrobial activity against most multiple-antibiotic-resistant E. coli isolates at the concentrations ranging from 4 to 16 μg/ml. Combination studies showed that mastoparan-AF acts synergistically with certain antibiotics, i.e., cephalothin or gentamicin, against some multiple-antibiotic-resistant E. coli isolates. In conclusion, mastoparan-AF alone or in combination with other antibiotics could be promising as alternatives for combating multiple-antibiotic-resistant E. coli in future clinical applications.

Topics: Amino Acid Sequence; Ampicillin; Animals; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Cephalothin; Chloramphenicol; Diarrhea; Drug Resistance, Multiple, Bacterial; Drug Synergism; Escherichia coli; Escherichia coli Infections; Genes, Bacterial; Gentamicins; Microbial Sensitivity Tests; Neomycin; Sus scrofa; Swine; Swine Diseases; Tetracycline; Wasp Venoms

Limited data regarding the susceptibility of Actinobacillus pleuropneumoniae to antimicrobials has been published during recent years. Accordingly, the aim of the present study was to investigate the distribution of MICs for the isolates of A. pleuropneumoniae from diseased pigs in the Czech Republic between 2007 and 2009. A total of 242 isolates were tested for susceptibility to 16 antimicrobial agents by a broth microdilution method. A low degree of resistance was observed for florfenicol (0.8%), amoxicillin and clavulanic acid (0.8%), tilmicosin (1.2%), tiamulin (1.7%) and ampicillin (3.3%), whereas resistance to tetracycline was detected more frequently, 23.9% of isolates. Interestingly, resistance to florfenicol has not yet been reported in any study investigating antimicrobial resistance of A. pleuropneumoniae. By PCR the presence of the floR gene was confirmed in all florfenicol resistant isolates.

Topics: Actinobacillus pleuropneumoniae; Amoxicillin; Ampicillin; Animals; Anti-Bacterial Agents; Clavulanic Acid; Czech Republic; Diterpenes; Genes, Bacterial; Microbial Sensitivity Tests; Swine; Swine Diseases; Tetracycline; Thiamphenicol; Tylosin

The aim of this study was to determine the prevalence, antimicrobial resistance and molecular epidemiology of Campylobacter coli isolated from swine in China. A total of 190 C. coli isolates obtained from two slaughter houses and ten conventional pig farms in Shandong (SD, n=95) and Ningxia (NX, n=95) provinces were tested for their susceptibility to 14 antimicrobials. A high prevalence (>95%) of ciprofloxacin and tetracycline-resistant strains was observed in both SD and NX. The erythromycin and clindamycin resistance rates of C. coli from NX (ERY: 54.7% CLI: 43.2%) were higher than those from SD (ERY: 37.9%, CLI: 35.8%). A significant difference (P<0.05) was observed in erythromycin resistance rate, but not (P>0.05) in clindamycin resistance rate. while the resistance rates of ampicillin and kanamycin in NX (AMP: 34.7%, KAN: 43.2%) were significantly lower (P<0.05) than those in SD (AMP: 51.6%, KAN: 71.6%). None of the tested isolates were resistant to phenicols. The majority of the isolates from both provinces (SD: 80% and NX: 73.7%) showed multi-drug resistance profiles. The point mutations of A2075G in the 23S rRNA and C257T in the gyrA gene were detected in 98% (87/89) of macrolide resistant isolates and all ciprofloxacin resistant isolates, respectively. In addition, all tetracycline-resistant isolates harbored the tet(O) gene. The high prevalence of antimicrobial resistance in C. coli strains derived from pigs in China was observed and was likely due to the extensive use of various antimicrobials. Prudent use of antimicrobial agents on farms should be further emphasized to control the dissemination of antimicrobial resistant C. coli.

Topics: Abattoirs; Animals; Anti-Bacterial Agents; Campylobacter coli; China; Ciprofloxacin; Clindamycin; Drug Resistance, Multiple, Bacterial; Erythromycin; Microbial Sensitivity Tests; Swine; Swine Diseases; Tetracycline

An in vivo experiment was conducted to evaluate the effects of tetracycline and zinc on pig colonization and transmission of methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 398. Eight piglets naturally colonized with MRSA ST398 and 8 MRSA-negative piglets of the same age and breed were assigned to three groups treated with tetracycline and zinc (Group 1), zinc (Group 2) or tetracycline alone (Group 3) and one non-treated group (Group 4), each containing two MRSA-positive and two MRSA-negative animals. Two additional non-treated control groups composed of only MRSA-positive (Group 5) and MRSA-negative (Group 6) animals were used to check for stability of MRSA carriage status. Nasal swabs and environmental wipes were collected on Days 0, 7, 14, and 21, and the occurrence of MRSA in each sample was quantified by bacteriological counts on Brilliance™ MRSA agar. Significantly higher nasal MRSA counts were observed in the zinc-treated (p=0.015) and tetracycline-treated (p=0.008) animals compared to the non-treated animals. Environmental MRSA counts appeared to increase over time in Groups 1 and 2 but such an increase was not statistically significant. MRSA-negative animals housed with MRSA-positive animals became positive in all groups, whereas the carriage status of the animals in Groups 5 and 6 did not change. This study demonstrates that feed supplemented with tetracycline or zinc increases the numbers of MRSA ST398 in the nasal cavity of pigs. Transmission of MRSA from positive to negative animals housed within the same pen was not influenced by exposure to these agents.

Topics: Animals; Anti-Bacterial Agents; Methicillin-Resistant Staphylococcus aureus; Nasal Cavity; Sus scrofa; Swine; Swine Diseases; Tetracycline; Zinc

The trimethoprim resistance gene dfrK was found to be part of the novel Tn554-related transposon Tn559 integrated in the chromosomal radC gene of a porcine methicillin-susceptible Staphylococcus aureus ST398 strain. While Tn559 and Tn554 had similar arrangements of the transposase genes tnpA, tnpB, and tnpC, the Tn554-associated resistance genes erm(A) and spc were replaced by dfrK in Tn559. Circular forms of Tn559 were detected and suggest the functional activity of this transposon.

Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Base Sequence; DNA Transposable Elements; Female; Methicillin; Molecular Sequence Data; Sequence Analysis, DNA; Staphylococcal Infections; Staphylococcus aureus; Swine; Swine Diseases; Trimethoprim Resistance

A novel ABC transporter gene, vga(C), was identified on the 14,365-bp multiresistance plasmid pKKS825 in a porcine methicillin (meticillin)-resistant Staphylococcus aureus isolate of sequence type 398. The vga(C) gene encodes a 523-amino-acid protein which confers resistance not only to streptogramin A antibiotics but also to lincosamides and pleuromutilins. Plasmid pKKS825 also carries the resistance genes aadD, tet(L), and dfrK, which may enable the coselection of vga(C) under selective pressure by kanamycin/neomycin, tetracyclines, and trimethoprim.

Topics: Animals; Anti-Bacterial Agents; ATP-Binding Cassette Transporters; Bacterial Proteins; Diterpenes; Drug Resistance, Multiple, Bacterial; Kanamycin; Lincosamides; Methicillin-Resistant Staphylococcus aureus; Molecular Sequence Data; Neomycin; Plasmids; Pleuromutilins; Polycyclic Compounds; Staphylococcal Infections; Streptogramin A; Swine; Swine Diseases; Tetracyclines; Trimethoprim

Four groups of six specific pathogen-free (SPF) pigs were inoculated intranasally with Actinobacillus pleuropneumoniae serotype 2 and treated with either enrofloxacin, tetracycline or penicillin at the onset of clinical disease, or left untreated. A fifth group was left uninoculated. The inoculated control and the penicillin-treated groups developed severe disease, but the groups treated with enrofloxacin and tetracycline recovered rapidly. All the inoculated pigs, except those treated with enrofloxacin developed serum antibodies to A pleuropneumoniae. On day 28, all five groups were challenged with A pleuropneumoniae without any subsequent treatment. The previously uninoculated control group and the enrofloxacin-treated group developed severe disease, but the three seropositive groups remained unaffected.

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Anti-Bacterial Agents; Antibodies, Bacterial; Disease Models, Animal; Enrofloxacin; Euthanasia, Animal; Fluoroquinolones; Penicillins; Respiratory Tract Diseases; Specific Pathogen-Free Organisms; Swine; Swine Diseases; Tetracycline

Topics: Animals; Bacterial Proteins; Drug Resistance, Bacterial; Enterococcus faecalis; Erythromycin; Gram-Positive Bacterial Infections; Humans; Methyltransferases; Microbial Sensitivity Tests; Swine; Swine Diseases

Topics: Animals; Chlamydia; Chlamydia Infections; Drug Resistance, Bacterial; Italy; Swine; Swine Diseases; Tetracycline

A total of 101 Actinobacillus pleuropneumoniae isolates from diseased pigs taken from across Japan during 2002 to 2005 were examined for antimicrobial susceptibility. All isolates were susceptible to ceftiofur, erythromycin, florfenicol and enrofloxacin. Antimicrobial-resistant isolates to oxytetracycline (OTC) (27.7%), dihydrostreptomycin (10.9%), thiamphenicol (10.9%), kanamycin (5.9%), trimethoprim (4.0%) and ampicillin (2.0%) were recognized. OTC-resistant isolates taken from 1986 to 2005 were examined for the tetracycline resistance gene. In OTC-resistant isolates, tetB has been the most frequently isolated gene in Japan. It is likely that the dissemination of tetB has contributed to the increased OTC resistance of A. pleuropneumoniae in Japan.

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Anti-Bacterial Agents; Japan; Microbial Sensitivity Tests; Swine; Swine Diseases; Tetracycline; Tetracycline Resistance

The incidence of antimicrobial resistance and expressed and unexpressed resistance genes among commensal Escherichia coli isolated from healthy farm animals at slaughter in Great Britain was investigated. The prevalence of antimicrobial resistance among the isolates varied according to the animal species; of 836 isolates from cattle tested only 5.7% were resistant to one or more antimicrobials, while only 3.0% of 836 isolates from sheep were resistant to one or more agents. However, 92.1% of 2480 isolates from pigs were resistant to at least one antimicrobial. Among isolates from pigs, resistance to some antimicrobials such as tetracycline (78.7%), sulphonamide (66.9%) and streptomycin (37.5%) was found to be common, but relatively rare to other agents such as amikacin (0.1%), ceftazidime (0.1%) and coamoxiclav (0.2%). The isolates had a diverse range of resistance gene profiles, with tet(B), sul2 and strAB identified most frequently. Seven out of 615 isolates investigated carried unexpressed resistance genes. One trimethoprim-susceptible isolate carried a complete dfrA17 gene but lacked a promoter for it. However, in the remaining six streptomycin-susceptible isolates, one of which carried strAB while the others carried aadA, no mutations or deletions in gene or promoter sequences were identified to account for susceptibility. The data indicate that antimicrobial resistance in E. coli of animal origin is due to a broad range of acquired genes.

Topics: Amikacin; Amoxicillin-Potassium Clavulanate Combination; Animals; Anti-Infective Agents; Cattle; Cattle Diseases; Ceftazidime; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Infections; Gene Expression Regulation, Bacterial; Microbial Sensitivity Tests; Polymerase Chain Reaction; Prevalence; Reverse Transcriptase Polymerase Chain Reaction; Sheep, Domestic; Streptomycin; Swine; Swine Diseases; Tetracycline; United Kingdom

Between March and October 2003 a field study was conducted in 50 randomly selected pig herds to assess the degree of tetracycline-resistance in lactose-positive enteric coliforms (LPEC) originating from fattening pigs and to evaluate the combined effects of various husbandry conditions on the development and persistence of antimicrobial-resistant bacteria. Data on housing, management and antimicrobial-drug consumption were collected, as well as faecal samples at three production stages: end of the nursery period (mean age: 72 days), end of the grower period (mean age: 125 days) and end of the finisher period (mean age: 186 days). The degree of tetracycline-resistant LPEC was determined by means of an agar dilution method. Tetracycline-resistant LPEC were found in every herd. The overall degree of tetracycline-resistance in LPEC was 56.8% (S.D. 22.4%). Only a very weak relation was found between the degrees of TETR in the different production stages within the same herd, indicating that the degree of TETR is mainly associated with the production stage rather than with the farm as a whole. The risk factor analysis showed that besides the antimicrobial-drug use, other factors like inside pen hygiene can influence the development and maintenance of antimicrobial-resistant bacteria in the gastrointestinal tracts of pigs. It was also observed that tetracycline-resistance in commensal Escherichia coli is often linked with resistance to other antimicrobial drugs like ampicillin and trimethoprim-sulphonamides. These results illustrate that the epidemiology of antimicrobial resistance is influenced by antimicrobial-drug use, cross-resistance development and non-antimicrobial risk factors.

Topics: Animal Husbandry; Animals; Anti-Bacterial Agents; Belgium; Colony Count, Microbial; Drug Resistance, Multiple, Bacterial; Enterobacteriaceae; Enterobacteriaceae Infections; Feces; Lactose; Microbial Sensitivity Tests; Risk Factors; Surveys and Questionnaires; Swine; Swine Diseases; Tetracycline; Tetracycline Resistance

The enterotoxigenic Escherichia coli (ETEC) strain Ec2173, causing post weaning diarrhoea in swine, harbours six plasmids ranging from 13 to 200 kb in size. The heat stable toxin genes sta, stb and a tetracycline resistance gene were located on a self conjugative 120-kb plasmid, called pTC. In the cloned ColE1 type origin of replication of pTC a deletion was detected compared to other ColE1 replicons affecting the replication modulator gene rom. Epidemiological studies on ETEC isolates showed that pTC-like plasmids are widely distributed among porcine ETEC strains; thus representing an example of co-evolution of antibacterial resistance and virulence in pathogenic E. coli.

Topics: Animals; Conjugation, Genetic; Diarrhea; Enterotoxins; Escherichia coli; Escherichia coli Infections; Fimbriae, Bacterial; Fluorine Radioisotopes; Plasmids; Replication Origin; Swine; Swine Diseases; Tetracycline; Virulence; Weaning

The aim of this study was to determine antimicrobial resistance, to evaluate and compare the use of two genotyping methods for molecular epidemiology purposes, and to determine the genotypic diversity of Campylobacter coli of porcine origin. A total of 100 C. coli isolates from swine were tested for susceptibility to six antimicrobials using the agar dilution method and genotyped using two high-resolution fingerprinting approaches: multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Evaluation of the methods was based on their resistance patterns, discriminatory indexes (DI), high test throughputs, costs, and turnaround times. Resistance to erythromycin and tetracycline was the most common. Both genotypic methods were found to have high discriminatory power, although MLST had a higher DI (0.936) than PFGE (DI = 0.889). It also had a higher throughput than PFGE. Isolates were clustered into 27 groups by MLST compared to 11 by PFGE. MLST was able to further discriminate the isolates grouped under the same cluster by PFGE. Out of the 65 MLST sequence types (STs) identified among the total isolates, 50 were reported for the first time. Most STs were found to be specific to the farm (n = 38) and to slaughter (n = 22). Resistance against tetracycline and erythromycin was encoded by the tet(O) gene and a A2075G point mutation in the 23S rRNA gene, respectively. A high ciprofloxacin MIC (>64 microg/liter) was conferred by a point mutation in the gyrA gene. The weak clonal structure of the C. coli population among swine was further highlighted by the index of association value of 0.293. The findings of this study indicate that multidrug-resistant diverse C. coli strains exhibiting resistance to ciprofloxacin and erythromycin are concerning, since these are the drugs of choice for treating invasive campylobacteriosis cases in humans.

Topics: Abattoirs; Animals; Animals, Domestic; Anti-Bacterial Agents; Campylobacter coli; Campylobacter Infections; Ciprofloxacin; Costs and Cost Analysis; DNA Gyrase; Drug Resistance, Multiple, Viral; Electrophoresis, Gel, Pulsed-Field; Erythromycin; Evaluation Studies as Topic; Genetic Variation; Microbial Sensitivity Tests; Mutation; Sequence Analysis, DNA; Species Specificity; Swine; Swine Diseases; Tetracycline; United States

The objective of this study was to determine the most efficient means of sampling faeces of finisher pigs for accurate and precise farm-level estimates of antimicrobial resistance among faecal Escherichia coli. Resistance to tetracycline and gentamicin of 8250 isolates of E. coli from 55 finisher pigs on one farm was measured with a hydrophobic grid membrane filter method. The between-pig, within-pen component of variance in resistance was large (97.5%), while between-pen, within-room and between-room components were small (2.5% and 0%, respectively). Using these resistance data, the abilities of two sampling strategies to estimate prevalence were modelled with a Monte Carlo 'bootstrap' procedure. Compositing faecal samples from several pigs before testing produced unbiased and precise estimates of prevalence and is simpler technically than individual animal testing.

Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Microbial; Escherichia coli; Escherichia coli Infections; Feces; Female; Gentamicins; Male; Microbial Sensitivity Tests; Random Allocation; Specimen Handling; Swine; Swine Diseases; Tetracycline; Tetracycline Resistance

This study was conducted to compare the Minimal Inhibitory Concentrations (MICs) for enrofloxacin, lincomycin, tetracycline, tiamulin and tylosin, of Mycoplasma hyosynoviae, isolated from pigs at notably different intervals (1968-71 and 1995-96). Each group comprised 21 low passage isolates and a Danish reference strain (M60) and the type strain (S16). MICs were determined in liquid medium with both initial and final readings. Enrofloxacin, lincomycin, tetracycline and tiamulin were active against all isolates, and tiamulin showed the highest activity. For tylosin all the isolates from 1968-71 were highly susceptible, whereas the isolates from 1995-96 could be divided into a highly susceptible (nine isolates) and relatively resistant (12 isolates) group. This difference between old and new strains was statistically significant (p = 0.0000415). The remaining agents, enrofloxacin, lincomycin, tiamulin and tetracycline, showed an unaltered good activity against M. hyosynoviae. The resistance to tylosin seems now to occur so often that this antibiotic cannot be recommended for therapeutic use any more. The most probable explanation for the emergence of resistance is the intensive use of tylosin during many years for therapy and growth promotion.

Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Diterpenes; Enrofloxacin; Fluoroquinolones; Lincomycin; Microbial Sensitivity Tests; Mycoplasma; Mycoplasma Infections; Quinolones; Swine; Swine Diseases; Tetracycline; Tylosin

Fifty-four Japanese strains of Mycoplasma hyosynoviae isolated from porkers during 1980 to 1995, and 107 Japanese strains of M. hyorhinis isolated from piglets with respiratory disease during 1991 to 1994 were investigated for the in vitro activities of 13 antimicrobial agents [josamycin, tylosin, spiramycin, kitasamycin, erythromycin, lincomycin (LCM), kanamycin (KM), chloramphenicol (CP), thiamphenicol (TP), tiamulin (TML), oxytetracycline (OTC), chlortetracycline (CTC), and enrofloxacin (ERFX)] by the agar dilution method. Of the drugs tested TML showed the highest activity with minimum inhibitory concentration (MIC) of 0.013 to 0.1 microgram/ m/ (MIC90; 0.05 microgram/ml) against strains of M. hyosynoviae, and 0.2 to 0.78 microgram/ml (MIC90; 0.39 microgram/ml) against strains of M. hyorhinis. ERFX, LCM, most of the 16-membered macrolide antibiotics and tetracyclines also showed low MICs against both mycoplasma species. The susceptibility of KM, CP and TP to the mycoplasmas was considered to be of a secondary grade. Two of 54 strains of M. hyosynoviae, and 11 of 107 strains of M. hyorhinis showed resistance to all 14- and 16-membered macrolide antibiotics tested. Tetracyclines (OTC and CTC) showed a relatively broad MIC distribution from 0.1 to 6.25 micrograms/ml against the M. hyosynoviae strains tested. All of the strains isolated during 1980 to 1984 were susceptible at the concentration of 0.78 microgram/ml or less (MIC90; 0.78 microgram/ml) to OTC and 1.56 micrograms/ml or less (MIC90; 1.56 micrograms/ml) to CTC, while the susceptibility of strains isolated recently, during 1994 to 1995, was more than 0.78 microgram/ml (MIC90; 3.13 micrograms/ml) to OTC, and more than 1.56 micrograms/ml (MIC90; 6.25 micrograms/ml) to CTC.

Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Antibiotics, Antitubercular; Chloramphenicol; Diterpenes; Dose-Response Relationship, Drug; Drug Resistance, Microbial; Enrofloxacin; Erythromycin; Fluoroquinolones; In Vitro Techniques; Josamycin; Kanamycin; Kitasamycin; Lincomycin; Mycoplasma; Mycoplasma Infections; Quinolones; Spiramycin; Swine; Swine Diseases; Tetracycline; Thiamphenicol; Tylosin

Topics: Animals; Anti-Bacterial Agents; Australia; Dimetridazole; Diterpenes; Dysentery; Lincomycin; Microbial Sensitivity Tests; Spectinomycin; Swine; Swine Diseases; Tetracycline; Treponema; Treponemal Infections; Tylosin

A field study was conducted on Ossabaw Island, Georgia (USA) to determine the feasibility of delivering oral vaccines to wild swine (Sus scrofa). Baits were made of polymerbound fish meal and contained a gelatin capsule as a potential vaccine chamber. Two biomarkers, iophenoxic acid and tetracycline, were incorporated into each bait, and soured chicken mash was used as an attractant. Baits (n = 1,980) were distributed in a grid pattern on a 405-ha test site and monitored for animal disturbance. Within 72 hr, 88% of 393 monitored baits were gone, and observations of track-beds surrounding 100 baits indicated that at least 52% were taken by wild swine. Subsequent testing of 80 wild swine for the biomarkers revealed that 95% of the animals had consumed bait. Track-bed observations indicated that raccoons (Procyon lotor) were the only non-target animal that frequently took baits. Biomarker analyses indicated 44% of 16 raccoons tested had eaten bait. It was concluded that oral vaccine delivery to wild swine should be considered as a feasible method of control or eradication of pseudorabies and/or swine brucellosis in wild swine if effective vaccines become available.

Topics: Administration, Oral; Animals; Animals, Wild; Brucella Vaccine; Brucellosis; Herpesvirus 1, Suid; Iodine; Pseudorabies; Raccoons; Swine; Swine Diseases; Tetracycline; Vaccines; Viral Vaccines

Topics: Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Animals; Clavulanic Acids; Diarrhea; Drug Combinations; Drug Therapy, Combination; Escherichia coli; Escherichia coli Infections; Injections, Intramuscular; Remission Induction; Sulfadiazine; Swine; Swine Diseases; Tetracycline; Time Factors; Trimethoprim

Cultural examination of cecal contents from 109 market weight hogs slaughtered in Prince Edward Island during May-July 1988 yielded 62 isolates of Campylobacter coli and seven Campylobacter jejuni. A commercial latex agglutination test helped to confirm the identification of Campylobacter. When tested against four drugs: erythromycin, tetracycline, kanamycin and ampicillin, 11 isolates showed multiple resistance. Resistance to erythromycin was seen in 19% and 28.6% of Campylobacter coli and Campylobacter jejuni respectively. All the isolates were susceptible to nitrofurans, gentamicin and chloramphenicol.

Topics: Ampicillin Resistance; Animals; Anti-Bacterial Agents; Campylobacter; Campylobacter fetus; Campylobacter Infections; Cecum; Drug Resistance, Microbial; Erythromycin; Kanamycin; Prince Edward Island; Swine; Swine Diseases; Tetracycline

The minimal inhibitory concentrations (MIC) of five tetracyclines and ten other antimicrobial agents were determined for four porcine bacterial respiratory tract pathogens by the agar dilution method. For the following oxytetracycline-susceptible strains, the MIC50 ranges of the tetracyclines were: P. multocida (n = 17) 0.25-0.5 micrograms/ml; B. bronchiseptica (n = 20) 0.25-1.0 micrograms/ml; H. pleuropneumoniae (n = 20) 0.25-0.5 micrograms/ml; S. suis Type 2 (n = 20) 0.06-0.25 micrograms/ml. For 19 oxytetracycline-resistant P. multocida strains the MIC50 of the tetracyclines varied from 64 micrograms/ml for oxytetracycline to 0.5 micrograms/ml for minocycline. Strikingly, minocycline showed no cross-resistance with oxytetracycline, tetracycline, chlortetracycline and doxycycline in P. multocida and in H. pleuropneumoniae. Moreover, in susceptible strains minocycline showed the highest in vitro activity followed by doxycycline. Low MIC50 values were observed for chloramphenicol, ampicillin, flumequine, ofloxacin and ciprofloxacin against P. multocida and H. pleuropneumoniae. B. bronchiseptica was moderately susceptible or resistant to these compounds. As expected tiamulin, lincomycin, tylosin and spiramycin were not active against H. pleuropneumoniae. Except for flumequine, the MIC50 values of nine antimicrobial agents were low for S. suis Type 2. Six strains of this species showed resistance to the macrolides and lincomycin.

Topics: Animals; Anti-Bacterial Agents; Bacteria; Bordetella; Chlortetracycline; Doxycycline; Haemophilus; Microbial Sensitivity Tests; Minocycline; Oxytetracycline; Pasteurella; Respiratory Tract Infections; Streptococcus; Swine; Swine Diseases; Tetracycline; Tetracyclines

Topics: Animals; Drug Therapy, Combination; Female; Oxytocics; Pregnancy; Puerperal Disorders; Swine; Swine Diseases; Tetracycline

Streptococcus suis type II was isolated from 170 pigs submitted to a veterinary diagnostic laboratory in Ontario, Canada, over a 1-year period. The most common disease condition with which the organism was identified was suppurative bronchopneumonia, usually secondary to enzootic pneumonia of pigs. The organism was also isolated in cases of pleuropneumonia, valvular endocarditis, arthritis, and vaginitis as well as from aborted fetuses. A condition characterized by neonatal disease and rapid death, usually within the first 24 hours of life, was identified in 23 pigs from 5 farms. Meningitis was identified in 15 weaned pigs from 8 farms. All S suis type II isolates tested for antimicrobial sensitivity were sensitive to penicillin and ampicillin. Most isolates were also sensitive to chloramphenicol and trimethoprim-sulfamethoxazole, but resistant to streptomycin and tetracycline. Accessions from which the organism was isolated were concentrated in the colder months of the year, with few or no isolates recorded in the summer months.

Topics: Animals; Animals, Newborn; Bronchopneumonia; Female; Lung; Penicillins; Seasons; Streptococcal Infections; Streptococcus; Swine; Swine Diseases; Tetracycline

Weanling pigs in groups of 12 were infected orally with Salmonella choleraesuis and were treated intramuscularly with doses of cephamycin C ranging from 12.5 to 337.5 mg twice daily for 10 days beginning 1 day postinoculation. Pigs in two other infected groups either received 300 mg of tetracycline orally on a similar schedule or served as nonmedicated controls. Optimal responses to cephamycin C were achieved at a twice daily dose of 112.5 mg. With this regimen, the febrile response was significantly reduced on day 2 and eliminated by day 5 postinfection, and the shedding of Salmonella spp. in feces was eliminated by day 5 postinfection; essentially, no lesions were found in the gastrointestinal tract at necropsy (day 26 postinfection). There was no mortality among recipients of the 112.5-mg dose; diarrhea was present on only 2% of the observation days. In contrast, 83% of the infected, nonmedicated pigs and 25% of the tetracycline-medicated pigs died, and diarrhea was present in these groups on 63 and 54% of the observation days, respectively. The striking benefits of cephamycin C treatment was achieved without adverse reactions. The weight gain and feed efficiency of the infected pigs treated with the 112.5-mg dose of cephamycin C and the noninfected, nonmedicated control pigs were equivalent.

Topics: Animals; Cephalosporins; Cephamycins; Feces; Female; Male; Salmonella Infections, Animal; Swine; Swine Diseases; Tetracycline

Experiments were conducted to study transfer of an enterotoxin (Ent) plasmid from a porcine enteropathogenic Escherichia coli to an E coli K12 strain in the intestine of newly weaned pigs. The Ent plasmid carried genes for resistance to tetracycline, streptomycin, and sulfonamides, thereby permitting a selection for tetracycline-resistant exconjugants in the feces of the pigs. In vivo transfer of the Ent plasmid was demonstrated to occur when the pigs were given large oral inocula of donor and recipient cultures, 1 hour apart. Differences in extent of transfer were not detected in pigs given antibiotic-free feed compared with littermates on feed containing oxytetracycline at 50 g/ton. In one experiment, tetracycline-resistant Ent- exconjugants were found which appeared to have received an R plasmid from an enteropathogenic type of E coli resident in the intestine.

Topics: Animals; Diarrhea; Drug Resistance, Microbial; Enterotoxins; Escherichia coli; Escherichia coli Infections; Feces; Intestines; Oxytetracycline; Plasmids; R Factors; Swine; Swine Diseases; Tetracycline

Distribution of tetracyclines and their effect on interaction of the cells in the immune response were studied on pigs and rabbits non-vaccinated, immunized with formolvaccin against paratyphoid fever and experimentally infected with the paratyphoid causative agent. It was found that oxytetracycline and tetracycline administered parentally to the animals formed complexes with the proteins and especially with albumins and gamma-globulins, were rapidly adsorbed by the lymphocytes and consumed by the cells of the reticulo-macro- and micro-phage systems, epithelium of the kidney cannaculi and the cells of the liver parenchyma. Immunomorphological changes accompanied by formation of antibodies to the antibiotics were found in the bloodforming-lymphoid system after repeated parental administrations of the tetracyclines. The titers of the antibodies to oxytetracycline and tetracycline were high by the 5th--14th day after the antibiotic administration and the relatively high levels persisted for 1.5 months. The use of tetracyclines during the induction stage of immunogenesis had a pronounced inhibitory effect on development of immunity against the paratyphoid fever antigen. On the basis of the tetracycline capacity for binding with immunoglobulins and intensive adsorption by the lymphocytes it is possible to suppose that the inhibitory effect of the antibiotics on immunogenesis was connected with their blocking the receptors of T- and B-lymphocytes.

Topics: Animals; Antibodies; Antibody Formation; Antibody-Producing Cells; Formaldehyde; Immunity, Cellular; Immunization; Leukocyte Count; Oxytetracycline; Paratyphoid Fever; Plasma Cells; Rabbits; Swine; Swine Diseases; Tetracycline; Tetracyclines; Time Factors

Topics: Animals; Drug Resistance, Microbial; Escherichia coli; Extrachromosomal Inheritance; Parathyroid Diseases; Salmonella; Swine; Swine Diseases; Tetracycline

The effect of chlortetracycline fed at concentrations of 10 or 20 grams per ton on the antibiotic resistance of fecal coliforms from weaned pigs from four different farms was studied. At admission to experimental quarters, coliforms resistant to at least one antibiotic predominated in all groups of animals. In pigs from three farms, chlortetracycline caused a reduction in the proportion of sensitive coliforms excreted, the extent of reduction depending on feeding practices on the farm of origin. In another experiment using pigs from a fourth farm, almost all coliforms isolated were resistant. Of all resistant strains isolated, those carrying resistance to a multiplicity of antibiotics predominated, and resistance to tracycline unaccompanied by that to other agents was relatively infrequent. Special studies of hemolytic coliforms from pigs from one farm identified two particular antibiotic sensitive types. No further isolations of these types were made once chlortetracycline administration began although 21 additional isolates were made from littermates receiving unsupplemented ration. These findings suggest that the elimination of sensitive strains resulting from chlortetracycline administration was due to a replacement of these strains by different resistant types rather than by acquisition of resistance by previously sensitive strains.

Topics: Administration, Oral; Animal Feed; Animals; Chlortetracycline; Drug Resistance, Microbial; Escherichia coli; Feces; Microbial Sensitivity Tests; Rectum; Salmonella Infections, Animal; Streptomycin; Swine; Swine Diseases; Tetracycline

The antibiotic resistance patterns of coliforms in faecal specimens from pigs and their human contacts were studied. The ability of the resistant coliforms to transfer their resistance in vitro to antibiotic-sensitive recipients was examined. The results showed that pigs which had received antibiotics carried more multiply-resistant, R-factor bearing coliforms than pigs which had not been given antibiotics. Human contacts of the antibiotic-treated pigs had a higher incidence of antibiotic-resistant coliforms with R-factors than human contacts of pigs which had not been given antibiotics. It is concluded that antibiotic treatment of farm animals may lead to acquisition of antibiotic resistance by gut coliforms of man.

Topics: Ampicillin; Animals; Chloramphenicol; Disease Reservoirs; Extrachromosomal Inheritance; Feces; Humans; Penicillin Resistance; Streptomycin; Sulfonamides; Swine; Swine Diseases; Tetracycline; Zoonoses

Topics: Animals; Anti-Bacterial Agents; Erysipelothrix Infections; Erythromycin Ethylsuccinate; Kanamycin; Microbial Sensitivity Tests; Neomycin; Novobiocin; Penicillins; Streptomycin; Swine; Swine Diseases; Tetracycline

Topics: Adolescent; Adult; Age Factors; Aged; Animals; Balantidiasis; Balantidium; Child; Child, Preschool; Disasters; Disease Outbreaks; Feces; Female; Humans; Infant; Male; Micronesia; Middle Aged; Sanitation; Sex Factors; Swine; Swine Diseases; Tetracycline

Topics: Actinobacillus; Actinobacillus Infections; Animals; England; Kidney; Kidney Cortex; Kidney Medulla; Necrosis; Swine; Swine Diseases; Tetracycline

Topics: Age Factors; Animals; Brucellosis; Brucellosis, Bovine; Cattle; Dog Diseases; Dogs; Goats; Humans; Occupational Diseases; Sex Factors; Sheep; Sheep Diseases; Streptomycin; Swine; Swine Diseases; Tetracycline; United States

Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Microbial; Salmonella; Salmonella Infections, Animal; Swine; Swine Diseases; Tetracycline

Topics: Ampicillin; Animals; Anti-Bacterial Agents; Australia; Cattle; Cattle Diseases; Chloramphenicol; Furazolidone; Microbial Sensitivity Tests; Penicillin Resistance; Salmonella; Salmonella Infections, Animal; Streptomycin; Swine; Swine Diseases; Tetracycline

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Bacitracin; Copper; Costs and Cost Analysis; Growth; Poultry Diseases; Swine; Swine Diseases; Tetracycline; United Kingdom

Fecal specimens were collected on 22 different Nebraska ranches and at the Department of Veterinary Science from young calves and pigs with neonatal diarrhea. Enterobacteriaceae isolated from these fecal specimens were screened for resistance to tetracycline, streptomycin, sulfamethizole, kanamycin, chloramphenicol, colistin, nitrofurantoin, and nalidixic acid. Of the 92 strains studied, 57 were resistant to one or more of these antimicrobial agents. Resistant strains were obtained from all herds involved in the study. The two most common resistance patterns were tetracycline streptomycin sulfamethizole (22 of 57) and tetracycline (13 of 57). None of the strains were resistant to chloramphenicol, colistin, nitrofurantoin, or nalidixic acid. The 57 resistant strains were studied to determine whether the resistance was transferable. Forty-three of the 57 resistant strains could transfer part or all of their resistance pattern to a drug-sensitive recipient. The 43 R(+) strains were obtained from 17 of the 23 herds studied. Considerable variation was observed between different R(+) strains in the frequency of transfer of resistance to a particular drug. In addition, variation in the frequency of transfer of different resistance determinants in individual R(+) strains was noted.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Chloramphenicol; Colistin; Conjugation, Genetic; Diarrhea; Drug Resistance, Microbial; Enterobacteriaceae; Escherichia; Escherichia coli; Extrachromosomal Inheritance; Kanamycin; Nalidixic Acid; Nitrofurantoin; Proteus; Streptomycin; Sulfamethizole; Swine; Swine Diseases; Tetracycline

Topics: Age Factors; Animal Diseases; Animals; Bronchopneumonia; Cattle; Chickens; Chlortetracycline; Delayed-Action Preparations; Ducks; Pasteurella Infections; Poultry Diseases; Rhinitis, Atrophic; Salmonella Infections, Animal; Swine; Swine Diseases; Tetracycline

Topics: Agar; Animals; Anti-Bacterial Agents; Chloramphenicol; Colistin; Diffusion; Dihydrostreptomycin Sulfate; Drug Resistance, Microbial; Escherichia coli; Escherichia coli Infections; Furazolidone; Hemolysis; Kanamycin; Microbial Sensitivity Tests; Neomycin; Paper; Serotyping; Swine; Swine Diseases; Tetracycline

Topics: Animals; Cattle; Cattle Diseases; Drug Resistance, Microbial; Escherichia coli; Escherichia coli Infections; Poultry Diseases; Salmonella typhi; Salmonella typhimurium; Streptomycin; Sulfonamides; Swine; Swine Diseases; Tetracycline

Topics: Animal Diseases; Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Chloramphenicol; Dog Diseases; Dogs; Drug Resistance, Microbial; Erythromycin; Horse Diseases; Horses; Lysostaphin; Penicillin Resistance; Rabbits; Staphylococcal Infections; Staphylococcus; Streptomycin; Swine; Swine Diseases; Tetracycline

Topics: Animals; Anti-Bacterial Agents; Leptospirosis; Protein Synthesis Inhibitors; Swine; Swine Diseases; Tetracycline

Topics: Animals; Anti-Bacterial Agents; Infections; Mycoplasma; Mycoplasma Infections; Oxytetracycline; Swine; Swine Diseases; Tetracycline