tiamulin and Poultry-Diseases

Pleuromutilins (tiamulin and valnemulin) are antimicrobial agents that are used mainly in veterinary medicine, especially for swine and to a lesser extent for poultry and rabbits. In pigs, tiamulin and valnemulin are used to treat swine dysentery, spirochaete-associated diarrhoea, porcine proliferative enteropathy, enzootic pneumonia and other infections where Mycoplasma is involved. There are concerns about the reported increases in the MICs of tiamulin and valnemulin for porcine Brachyspira hyodysenteriae isolates from different European countries, as only a limited number of antimicrobials are available for the treatment of swine dysentery where resistance to these antimicrobials is already common and widespread. The loss of pleuromutilins as effective tools to treat swine dysentery because of further increases in resistance or as a consequence of restrictions would present a considerable threat to pig health, welfare and productivity. In humans, only one product containing pleuromutilins (retapamulin) is authorized currently for topical use; however, products for oral and intravenous administration to humans with serious multidrug-resistant skin infections and respiratory infections, including those caused by methicillin-resistant Staphylococcus aureus (MRSA), are being developed. The objective of this review is to summarize the current knowledge on the usage of pleuromutilins, resistance development and the potential impact of this resistance on animal and human health.

Topics: Animals; Anti-Bacterial Agents; Brachyspira hyodysenteriae; Diterpenes; Drug Resistance, Bacterial; European Union; Humans; Microbial Sensitivity Tests; Mycoplasma Infections; Pleuromutilins; Polycyclic Compounds; Poultry; Poultry Diseases; Rabbits; Swine; Swine Diseases

Tiamulin hydrogen fumarate is a semisynthetic derivative of the diterpene antibiotic pleuromutilin used in poultry medicine to treat mainly Mycoplasma- and Brachyspira-related diseases. Its use over 30 yr has not generally increased the development of resistance to these pathogens but occasionally resistant isolates are encountered. Tiamulin administered at therapeutic levels is relatively quickly absorbed, metabolized in the liver, and eliminated from the body of the bird after a withdrawal period of 72 h, and as a result, meat products can be safely consumed. A zero withdrawal period for eggs has been granted in several European Union states. When administered with different drugs, tiamulin has been shown to have an enhanced activity with the tetracyclines. There is a strong interaction, even death, with the ionophore anticoccidials monensin, narasin, and salinomycin when tiamulin is used at therapeutic levels, but this is dose-related and low doses do not interact. It is thought to be caused by the preferential metabolism of tiamulin in the liver resulting in a build up of the ionophore leading to clinical signs of overdosage. Tiamulin shows a milder interaction, such as temporary growth depression, with maduramicin and semduramicin but is compatible with lasalocid. Although tiamulin shows small benefits in improving performance in healthy animals, its main production benefit is in the face of infection, as a true therapeutic antibiotic.

Topics: Animals; Anti-Bacterial Agents; Bacterial Infections; Diterpenes; Poultry; Poultry Diseases

This paper presents an overview of intestinal spirochete infections of chickens. It focuses particularly on studies in Australia, where recent surveys of 136 layer and broiler breeder flocks have revealed a high rate of infection (>40%) with intestinal spirochetes. Infection was not detected in broiler flocks. Approximately 50% of isolates from infected flocks were Brachyspira (Serpulina) intermedia or B. pilosicoli, with the other isolates being B. innocens, B. murdochii or the proposed species 'B. pulli'. No isolates of B. alvinipulli were found. Intestinal spirochetes were significantly associated with wet litter problems and/or reduced egg production. Experimental infection of point-of-lay birds with either B. intermedia or B. pilosicoli caused reduced egg production, and, with B. intermedia, a significant increase in fecal moisture content. Infection with B. innocens caused no significant changes. In-water treatment of a flock with a mixed spirochete infection using lincospectin resulted in a slimy diarrhea lasting for 2-3 weeks, followed by absence of spirochetes for 3 months. Birds treated with tiamulin remained healthy, and had a reduced level of infection with intestinal spirochetes (30%) for 3 months. Trials are under way to test the efficacy of antimicrobials in point-of-lay chickens experimentally infected with either B. intermedia or B. pilosicoli.

Topics: Animals; Australia; Brachyspira; Chickens; Diterpenes; Drug Therapy, Combination; Europe; Feces; Female; Lincomycin; Oviposition; Poultry Diseases; Prevalence; Spectinomycin; Spirochaetales Infections; Treatment Outcome; United States

Mycoplasma gallisepticum (M. gallisepticum) remains one of the most important diseases in poultry production. Controlling the impact of the disease is done by eradication of positive breeder flocks or by vaccination and medication. A widely used molecule in medication programs is tiamulin, a pleuromutilin antibiotic. Since recent data on the in vivo efficacy of this molecule are scarce, 2 challenge studies were conducted using a recently isolated M. gallisepticum strain belonging to the wildtype population with regard to its tiamulin and tetracycline minimum inhibitory concentration (MIC). In the first challenge study, the dose rate of tiamulin was tested. For this, broilers were infected with M. gallisepticum and treated with 10 mg or 25 mg tiamulin hydrogen fumarate (hf)/kg body weight (BW) for 5 successive days. In a second challenge study, the dose rate of tiamulin combined with chlortetracycline was tested. For this, broilers were infected with M. gallisepticum and treated with 6.25 mg tiamulin hf/18.75 mg chlortetracycline hydrochloride (hcl)/kg BW or 12.5 mg tiamulin hf/37.5 mg chlortetracycline hcl/kg BW for 5 successive days. Clinical scoring of respiratory signs, macroscopic scoring of respiratory tract lesions, M. gallisepticum isolation from the respiratory organs, weight gain, and mortality were the monitored efficacy parameters. The first study demonstrated that a 5-day 10 mg/kg BW tiamulin hf treatment provided significant protection against the M. gallisepticum infection. However, since the 5-day 25 mg/kg BW group was significantly better than the 10 mg/kg BW for reducing the post-treatment clinical signs and the M. gallisepticum numbers in the respiratory organs, the 25 mg/kg BW treatment is recommended for clinical M. gallisepticum infections. In the second study, the combined 12.5 mg tiamulin hf/37.5 mg chlortetracycline hcl/kg BW resulted in a significant reduction of the severity of clinical respiratory disease post treatment and a significant reduction of the M. gallisepticum numbers in the respiratory tract.

Topics: Animals; Anti-Bacterial Agents; Chickens; Chlortetracycline; Diterpenes; Dose-Response Relationship, Drug; Drug Combinations; Drug Therapy, Combination; Mycoplasma gallisepticum; Mycoplasma Infections; Poultry Diseases

The pleuromutilin antibiotic tiamulin (TIA) is known to produce a negative interaction in broilers when administered in combination with several ionophore anticoccidials such as salinomycin (SAL). Chlortetracycline (CTC), when administered simultaneously with TIA, has demonstrated a synergistic antimicrobial effect. A 35-d feeding study was conducted in cages to evaluate the interaction effect of a combination of TIA plus CTC at increasing inclusion levels when administered concurrently with SAL. A total of 200 one-day-old broiler chicks were distributed into 4 groups, and each group consisted of 5 cages containing 10 birds in each. Replicate cages were distributed randomly. Feed for all groups contained 60 ppm SAL, but additionally, 0, 20, 30, and 50 ppm TIA and 0, 60, 90, and 150 ppm CTC were included, respectively. Several enzymes (creatine phosphokinase, lactate dehydrogenase, and aspartate aminotransferase) were determined from blood samples taken at the end of the trial. Blood samples were also collected during d 0, 19, and 35 and were analyzed for antibody titers against Mycoplasma gallisepticum and Mycoplasma synoviae. Necropsy of a few birds (20, 8, 20, 12, and 12 on d 7, 14, 21, 28, and 35, respectively) was conducted at weekly intervals. Results indicated that there was a significant depression of weight gain (P < 0.05) in group 4 (TIA 50 + CTC 150) only. The final weights were 1,809 +/- 130, 1,859 +/- 52, 1,703 +/- 47, and 1,617 +/- 98 g for groups 1 (TIA 0 + CTC 0), 2 (TIA 20 + CTC 60), 3 (TIA 30 + CTC 90), and 4 (TIA 50 + CTC 150), respectively. However, feed intake and feed conversion efficiency (g of weight gain/kg of feed intake) were not significantly affected in any of the groups. There was no dose-related adverse effect on mortality or clinical signs exhibited during the trial, and this was supported by necropsy. Maternally derived antibodies against M. gallisepticum were present at the beginning of the trial but disappeared within 19 d. Otherwise, there was no apparent infection by M. gallisepticum or M. synoviae throughout the trial. The results demonstrate that 50 ppm TIA plus 150 ppm CTC along with 60 ppm SAL caused only a depression of growth, but no adverse signs of interaction were detected. Taking into consideration all the aspects of the cost of production, the 20 ppm TIA plus 60 ppm CTC was the most cost-effective level to administer continuously with 60 ppm SAL via the feed, but it would be important to do an additional stud

Topics: Animals; Anti-Bacterial Agents; Aspartate Aminotransferases; Body Weight; Chickens; Chlortetracycline; Coccidiostats; Creatine Kinase; Diterpenes; Drug Synergism; Female; L-Lactate Dehydrogenase; Male; Poultry Diseases; Pyrans

There has been much confusion over the significance of spirochaetes found in the caeca of laying hens and the impact they may have on egg production. In recent years, the situation has been made clearer and the presence of such species as Brachyspira pilosicoli have been shown to cause a mild, chronic disease in both layers and breeders and to reduce egg production by reportedly 5%. In the United Kingdom, a multi-age caged laying site with three separate flocks of approximately 12 000 birds each was chronically infected with B. pilosicoli but displayed few clinical signs except for a noticeable reduction in egg production and an increased mortality. The flocks were treated for 3 days in the drinking water with tiamulin at 12.5 mg/kg bodyweight, and a steady improvement in performance was recorded. The production results were compared with a flock that had been untreated with tiamulin previously, as a control, and one that had been treated at 25 and 45 weeks of age. A 9.8% improvement in egg production/hen housed up to 72 weeks of age and 9.7% in total egg weight was recorded, as well as an 8.6% reduction in actual hen mortality, in the tiamulin-treated flock in comparison with the untreated control. After taking into account the difference in breeds used, there was only a 6% reduction in egg production but an 8.84% increase in mortality in the untreated flock compared with the individual breed's standard production data. The cost of the disease was estimated at 14 million pound in the United Kingdom, based on a national laying flock of 30 million or 1.5% of production. Faecal examination for potentially pathogenic spirochaetes should be part of the differential diagnosis of under-performing laying flocks.

Topics: Animals; Anti-Bacterial Agents; Brachyspira; Chickens; Diterpenes; Female; Poultry Diseases; Spirochaetales Infections

The effect of fermented wheat germ extract (FWGE, Immunovet-HBM) was studied in chickens challenged with Mycoplasma gallisepticum. Ninety M. gallisepticum- and M. synoviae-free 3-wk-old chickens were exposed to aerosol infection of M. gallisepticum. One group (30 birds) was treated with FWGE, a second group with tiamulin, and a third group was untreated. The fourth group was exposed to PBS aerosol as a negative control. On d 9, all chickens were slaughtered and examined for the presence of gross and histological lesions, the presence of the challenge strain in the organs and specific antibodies in the serum. Body weight gains and feed conversion rates were recorded. In the groups treated with FWGE and with tiamulin, the chickens remained clinically healthy: their BW gains were 441.7 g and 446.8 g, respectively. Feed conversion ratios were 1.72 and 1.71 for FWGE- and tiamulin-treated birds, respectively. Control birds had BW gain of 480.8 g, and feed conversion ratio of 1.78. The numbers of birds with gross lesions (15 and 11, respectively) and lesion scores (25 and 25, respectively) of the FWGE- and tiamulin-treated groups were significantly lower than in the infected untreated group (25 birds, lesion score of 190). No mycoplasma was reisolated from brain, liver, spleen, heart, or kidneys of the FWGE-treated birds, and the number of mycoplasma isolations from the respiratory tract samples was less frequent (10) than from the infected untreated group (64). In addition, 35 samples from other internal organs were also positive. Twenty percent of the birds treated with FWGE showed serological response with a 5.0% reaction score, whereas in the infected untreated group, 83.3% of birds were reactors, with a 62.5% reaction score.

Topics: Animals; Anti-Bacterial Agents; Chickens; Diterpenes; Fermentation; Mycoplasma gallisepticum; Mycoplasma Infections; Plant Extracts; Poultry Diseases; Triticum

One hundred seventy-eight mycoplasma strains isolated from South African poultry flocks between 2003 and 2015 were identified by full-genome sequencing and phylogenetic analysis of the 16S rRNA gene and were classified as follows:

Topics: Animals; Anti-Bacterial Agents; Chickens; Chlortetracycline; Diterpenes; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests; Mycoplasma; Mycoplasma Infections; Phylogeny; Poultry Diseases; South Africa; Tylosin

Avian intestinal spirochaetosis (AIS) caused by Brachyspira spp., and notably Brachyspira pilosicoli, is common in layer flocks and reportedly of increasing incidence in broilers and broiler breeders. Disease manifests as diarrhoea, increased feed consumption, reduced growth rates and occasional mortality in broilers and these signs are shown in layers also associated with a delayed onset of lay, reduced egg weights, faecal staining of eggshells and non-productive ovaries. Treatment with Denagard® Tiamulin has been used to protect against B. pilosicoli colonisation, persistence and clinical presentation of AIS in commercial layers, but to date there has been no definitive study validating efficacy. Here, we used a poultry model of B. pilosicoli infection of layers to compare the impact of three doses of Denagard® Tiamulin. Four groups of thirty 17 week old commercial pre-lay birds were all challenged with B. pilosicoli strain B2904 with three oral doses two days apart. All birds were colonised within 2 days after the final oral challenge and mild onset of clinical signs were observed thereafter. A fifth group that was unchallenged and untreated was also included for comparison as healthy birds. Five days after the final oral Brachypira challenge three groups were given Denagard® Tiamulin in drinking water made up following the manufacturer's recommendations with doses verified as 58.7 ppm, 113 ppm and 225 ppm. Weight gain body condition and the level of diarrhoea of birds infected with B. pilosicoli were improved and shedding of the organism reduced significantly (p=0.001) following treatment with Denagard® Tiamulin irrespective of dose given. The level and duration of colonisation of organs of birds infected with B. pilosicoli was also reduced. Confirming previous findings we showed that the ileum, caeca, colon, and both liver and spleen were colonised and here we demonstrated that treatment with Denagard® Tiamulin resulted in significant reduction in the numbers of Brachyspira found in each of these sites and dramatic reduction in faecal shedding (p<0.001) to approaching zero as assessed by culture of cloacal swabs. Although the number of eggs produced per bird and the level of eggshell staining appeared unaffected, egg weights of treated birds were greater than those of untreated birds for a period of approximately two weeks following treatment. These data conclusively demonstrate the effectiveness of Denagard® Tiamulin in reducing B. pilosicoli infect

Topics: Animals; Anti-Bacterial Agents; Brachyspira; Chickens; Diterpenes; Dose-Response Relationship, Drug; Drinking Water; Female; Gram-Negative Bacterial Infections; Poultry Diseases

This study compares the antimicrobial susceptibility over time between two groups of Mycoplasma gallisepticum (MG) isolates from the same geographical area. Minimum inhibitory concentration of 13 antimicrobials was determined against two groups of MG isolates from chickens. Group 1 strains (n=22) were isolated in 2004-2005 while group 2 strains (n=7) were isolated in 2007-2008. Minimum inhibitory concentration 50 for group 1 versus group 2 was 4/4, 0.5/0.5, ≤ 0.031/≥ 64, ≤ 0.031/2, ≤ 0.031/0.125, 1/0.5, 1/1, ≤ 0.031/≤ 0.031, ≤ 0.031/2, ≤ 0.031/2, 1/4, ≤ 0.031/0.062, and 0.062/2 μg/ml against gentamicin, spectinomycin, erythromycin, tilmicosin, tylosin, florfenicol, thiamphenicol, tiamulin, ciprofloxacin, enrofloxacin, chlortetracycline, doxycycline, and oxytetracycline, respectively. There was a statistically significant increase in resistance of group 2 to erythromycin, tilmicosin, tylosin, ciprofloxacin, enrofloxacin, chlortetracycline, doxycycline, and oxytetracycline. This dramatic increase in resistance against 8 antimicrobials belonging to three different families of antimicrobials in a relatively short period of time appears to be rare and of concern. The cause of this increased resistance observed in group 2 of MG isolates was not determined and should be further investigated. Monitoring of MG field strain susceptibility is highly recommended to implement successful treatment and prophylaxis programs in endemic areas.

Topics: Animals; Anti-Bacterial Agents; Chickens; Diterpenes; Drug Resistance, Multiple; Microbial Sensitivity Tests; Mycoplasma gallisepticum; Mycoplasma Infections; Poultry Diseases

Histomonosis, a parasitic disease of galliformes and sporadically of other birds caused by Histomonas meleagridis, can result in very high mortality, especially in turkeys. The ban on the last antihistomonal drug prompted an urgent search for alternative prevention and treatment strategies. As both paromomycin and tiamulin have been reported to have antihistomonal activity, these antibiotics were investigated in vitro by adding two-fold serial dilutions ranging from 12.5 to 400 microg/mL to cultures of H. meleagridis. Controls (no antibiotics, or 12.5 microg or 400 microg/mL dimetridazole) were included. Parasites were counted after 3, 20, 28, 44, 51, and 71 hours of incubation. Tiamulin did not have a clear antihistomonal effect, but paromomycin had an inhibitory effect at all concentrations tested. The latter antibiotic was subsequently examined in an in vivo study. Five groups of 20 1-day-old poults, matched by weight and sex, were either not treated (infected and uninfected control groups) or treated with paromomycin (100, 200, or 400 ppm) added to their feed. After 2 weeks all groups, except for the uninfected control group, were intracloacally inoculated with 200,000 histomonads per bird. A clear dose-response effect was found for paromomycin. In the 100-ppm paromomycin group, mortality was similar to that in the untreated control group, whereas about half of the birds died in the 200-ppm paromomycin group; almost complete protection against histomonosis was seen in the 400-ppm paromomycin group. This study shows that paromomycin supplied in feed at 400 ppm is a potentially preventive strategy against H. meleagridis.

Topics: Animals; Antiprotozoal Agents; Diterpenes; Dose-Response Relationship, Drug; Paromomycin; Poultry Diseases; Protozoan Infections, Animal; Random Allocation; Time Factors; Treatment Outcome; Turkeys

Thirty individually caged layer hens were inoculated with Brachyspira intermedia, and 20 control birds remained unchallenged. Birds received a diet containing 100 parts/10(6) zinc bacitracin (ZnB), and were monitored for 10 weeks. B. intermedia was recovered sporadically from five of the inoculated birds, and there were no significant effects on body weight, faecal water or egg production. ZnB was presumed to be indirectly inhibiting spirochaete growth, and when removed from the diet, 18 of the 30 inoculated birds rapidly became culture positive. After 4 weeks, 10 of the 30 infected birds were treated with tiamulin at 25 mg/kg for 5 days, and 10 were returned to the diet containing ZnB. Birds receiving tiamulin became spirochaete negative and maintained their egg production, but re-infection occurred. The other 20 infected birds had a significant drop in egg production, but those receiving ZnB showed a reduced colonization by B. intermedia after 3 weeks.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Bacitracin; Cecum; Chickens; Diterpenes; Feces; Female; Oviposition; Poultry Diseases; Spirochaetales; Spirochaetales Infections; Time Factors; Treatment Outcome

Brachyspira pilosicoli strain CPSp1 isolated from a chicken in a broiler breeder flock in Queensland was used to experimentally infect 30 individually caged 22-week-old Cobb 500 broiler breeder hens. Another 10 birds were sham-inoculated with sterile broth. All birds failed to become colonized. At 29 weeks of age, all birds were transferred to a diet containing 50 parts/10(6) zinc bacitracin (ZnB) and were re-challenged with the same B. pilosicoli strain at 32 weeks of age, weekly for 5 weeks. The majority of the inoculated birds then became colonized, confirming previous findings that ZnB can increase susceptibility to colonization with B. pilosicoli. The control group remained uninfected. Infected groups tended to have an increased faecal water content and faecal staining of eggshells. Ten birds were then treated by crop tube with 25 mg/kg body weight tiamulin for 5 days, and 10 birds with 20 mg/kg body weight lincomycin for 5 days. Both treatments removed the infection, while untreated birds remained infected. The results support previous observations that ZnB at 50 parts/10(6) in the diet increases the susceptibility of birds to B. pilosicoli infection, and demonstrated the usefulness of both tiamulin and lincomycin for treatment of infection with B. pilosicoli in adult birds.

Topics: Animals; Anti-Bacterial Agents; Bacitracin; Chickens; Disease Susceptibility; Diterpenes; Female; Lincomycin; Oviposition; Poultry Diseases; Spirochaetales; Spirochaetales Infections

The efficacy of treatment with single dose administration of 5 drugs at different dosages to layer hens naturally infected with Mycoplasma gallisepticum was studied. The drugs were tiamulin, which was administered orally, tylosin (parenterally and orally), spiramycin (orally), long-acting oxytetracycline (parenterally) and tylosindihydrostreptomycin (parenterally). Cure was assessed by the absence of nasal discharge. The cure rate was significantly higher (P less than 0.05) in treated hens than in untreated hens, as early as 1 day after treatment. Remission for 33 days was achieved in 60% of hens treated with 100 mg oxytetracycline, in 100% of hens treated with 100 mg or 200 mg spiramycin, in 92% and 85% of hens treated with 100 mg tylosin, parenterally and orally, and in 89% and 88% of birds given 100 mg tiamulin and tylosin-dihydrostreptomycin, respectively.

Topics: Administration, Oral; Animals; Chickens; Dihydrostreptomycin Sulfate; Diterpenes; Drug Therapy, Combination; Injections, Intramuscular; Mycoplasma Infections; Oxytetracycline; Poultry Diseases; Spiramycin; Tylosin

The anticoccidial activity of semduramicin against laboratory isolates of five species of poultry Eimeria was investigated. In laboratory scale battery trials, semduramicin at 20 to 30 ppm demonstrated broad-spectrum anticoccidial efficacy equivalent to salinomycin at 60 ppm. Also, semduramicin at 25 ppm was fed to uninfected cockerels in batteries for 21 days, and growth rate and feed efficiency were found to be equivalent to birds fed salinomycin at 60 ppm. Semduramicin was well tolerated when coadministered with tiamulin. Semduramicin demonstrated the same activity whether produced by semisynthesis or by direct fermentation.

Topics: Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Diterpenes; Drug Therapy, Combination; Eimeria tenella; Ionophores; Male; Nigericin; Poultry Diseases

An investigation involving 640 turkeys demonstrated that the inclusion of lasalocid continuously from day-old to 16 weeks of age, at levels up to 375 ppm in the feed, produced no adverse effects; furthermore, the inclusion of 125 ppm lasalocid in the feed was compatible with the administration of 250 ppm tiamulin in the drinking water continuously for five days to turkeys over the same age range.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Body Weight; Coccidiosis; Diterpenes; Drinking; Eating; Female; Lasalocid; Male; Organ Size; Poultry Diseases; Turkeys

Healthy turkeys receiving 80 ppm monensin in their feed were injected at 26, 40 and 61 days of age with tiamulin at dosages of 12.5 and 25 mg/kg body weight. The aim of the study was to develop a regime for medicating with tiamulin turkeys receiving monensin in their feed, and which would circumvent the known toxicity created by the simultaneous administration of the two drugs. One injection of 12.5 mg/kg tiamulin up to the age of 61 days or 2 injections of 12.5 mg/kg tiamulin up to 40 days of age caused no mortality or adverse reaction.

Topics: Age Factors; Animal Feed; Animals; Anti-Bacterial Agents; Diterpenes; Drug Synergism; Furans; Growth Disorders; Injections, Intramuscular; Male; Monensin; Mycoplasma Infections; Poultry Diseases; Turkeys; Water

Topics: Animals; Chickens; Diterpenes; Drug Interactions; Furans; Monensin; Poultry Diseases

The minimal inhibitory concentrations (MIC) of tiamulin and tylosin for mycoplasma, Gram-positive, and Gram-negative micro-organisms isolated from chickens were determinated by the agar dilution method. Median MIC values for tiamulin against Mycoplasma gallisepticum (0.05 microgram/ml) and Mycoplasma synoviae (0.10 microgram/ml) were 2 to 4 times lower than the corresponding values for tylosin. Tiamulin was also slightly more effective in vitro in inhibiting Escherichia coli, Pasteurella multocida, and beta-haemolytic streptococci than was tylosin. Groups of chicken were offered tiamulin medicated drinking water at rates of 125 and 250 mg/litre for 48 hours. Average serum tiamulin concentrations were 0.38 and 0.78 microgram/ml, respectively. When tylosin tartrate was added to the drinking water at 500 and 700 mg/litre, average serum drug levels were 0.12 and 0.17 microgram/ml, respectively. Tiamulin was 45% bound in chicken serum, as against 30% serum protein binding for tylosin. Correlations were made between free (non protein bound) serum drug levels and the MIC values of the two drugs. Such comparisons suggest that when tiamulin is given in the drinking water at rates of 125 to 250 mg/litre, better antimycoplasmal activity is to be expected in vivo than by giving tylosin tartrate in the drinking water at 500 to 700 mg/litre. Based on these data, no clinical efficacy of these dose rates can be expected in flocks infected by gram-negative micro-organisms such as E. coli or P. multocida. The tylosin tartrate rate of 500 to 700 mg/litre, may be clinical ineffective the treatment of Staphylococcus aureus infections.

Topics: Animals; Anti-Bacterial Agents; Chickens; Diterpenes; Leucomycins; Microbial Sensitivity Tests; Mycoplasma Infections; Pasteurella; Pleuropneumonia, Contagious; Poultry; Poultry Diseases

The anticoccidial activities of monensin and lasalocid have been studied separately and in combination with tiamulin, a new pleuromutilin derivative. Combinations of constant tiamulin concentration (.0125%) in drinking water with various levels of polyether anticoccidials (6.3 to 125 ppm) in feed and conversely of constant levels of anticoccidials with various concentrations of tiamulin were used. The prophylactic efficacy of these combined treatments in battery raised broiler chickens infected with Eimeria tenella was evaluated. Assessment of the parameters mortality, weight gain, dropping scores, lesion scores, and oocyst output showed that simultaneous application of tiamulin significantly improved the anticoccidial activity of the polyethers. As tiamulin alone is without anticoccidial activity, this phenomenon was considered to result from an interaction between tiamulin and the polyethers leading to a slower metabolic degradation of the latter. Thus tissue levels adequate for maximum anticoccidial activity would be attained with lower polyether dose levels. Experiments using isolated perfused rat liver showed that elimination of monensin was reduced by 60% in the presence of tiamulin.

Topics: Animals; Anti-Bacterial Agents; Chickens; Coccidiosis; Coccidiostats; Diterpenes; Drug Synergism; Drug Therapy, Combination; Female; In Vitro Techniques; Lasalocid; Liver; Monensin; Poultry Diseases; Rats

To evaluate efficacy of Tiamuline in mycoplasmosis of chickens and turkeys under controlled field conditions 2 prophylactical and 3 therapeutical trials were conducted. The compound was administered via drinking water for 3 days in comparison to Tylosin tartrate. In both prophylactical and therapeutical tests, Tiamuline showed a superior efficiacy, as measured by clinical symptoms, pathological lesions and microbiological findings. Therefore, Tiamuline can be recommended for treatment of mycoplasmosis in chickens and turkeys in a dosage of 0.025% and in a dosage of 0.0125% for prophylaxis in flocks at risk.

Topics: Animals; Anti-Bacterial Agents; Chickens; Diterpenes; Female; Leucomycins; Mycoplasma Infections; Poultry Diseases; Turkeys