agar and Respiratory-Tract-Infections

A modified chocolate blood agar medium incorporating cefsulodin, a semi-synthetic cephalosporin, was developed and compared with non-selective chocolate blood agar and selective haemin-bacitracin blood agar for the routine isolation of Haemophilus influenzae from the respiratory secretions of patients with cystic fibrosis. The results showed that cefsulodin chocolate blood agar improved the recovery rate of H. influenzae in this group of patients. The medium was stable on storage for 10 days at 4 degrees C.

Topics: Agar; Bacitracin; Blood; Cacao; Cefsulodin; Cephalosporins; Culture Media; Cystic Fibrosis; Haemophilus Infections; Haemophilus influenzae; Hemin; Humans; Inhalation; Respiratory Tract Infections; Sputum

Respiratory tract infections cause significant morbidity and mortality globally and are the most common infectious diseases in humans. This study aims at assessing the presence of bacterial respiratory infections, number of people infected and antimicrobial susceptibility profile among antibiotic naïve outpatients presenting with respiratory tract infections in Meru Teaching and Referral Hospital.. The study was conducted in Meru Teaching and Referral Hospital, Meru County from April 2017 to August 2018. Upper respiratory infections were characterized by acute infection of nasal cavity, pharynx and larynx while lower respiratory infections were characterized by chest pains, prolonged cough, productive sputum, difficulty in breathing, fever and weight loss. A total of 384 sputum and throat samples were collected aseptically from patients who were clinically suspected to have respiratory infections and cultured in blood agar, MacConkey agar and chocolate agar. Bacterial isolates were identified by colonial morphology, Gram stain and confirmed by biochemical tests. Antimicrobial susceptibility profile was determined using agar disc diffusion method.. Respiratory bacterial pathogens were isolated in 45.6% of the samples. The prevalence of the bacteria species isolated were as follows Pseudomonas species (36.6%), Klebsiella species (20.6%), Staphylococcus aureus (16.6%), Streptococcus pyogenes (13.7%), Streptococcus pneumoniae (10.3%) and mixed isolates (2.3%). Amoxicillin and ampicillin recorded the highest resistance rate. Most of the isolates displayed high level of resistance to more than two antibiotics. Although multidrug resistance is reported in the study, gentamicin, amikacin and cefuroxime are recommended as the antibiotics of choice against bacterial isolates obtained.. Bacterial respiratory infections were prevalent in the study area and the isolates obtained showed resistance to commonly used antibiotics such as amoxicillin, ampicillin, ciprofloxacin piperacillin ciprofloxacin, ceftazidime, piperacillin-tazobactam and cephalexin. Therefore need for a continuous surveillance of antimicrobial resistance in management of respiratory infections in the study area.

Topics: Agar; Amoxicillin; Ampicillin; Anti-Bacterial Agents; Ciprofloxacin; Humans; Kenya; Outpatients; Piperacillin; Respiratory Tract Infections; Staphylococcal Infections

Animal models of chronic lung infection with P. aeruginosa (PA) are useful tools to improve antibiotic (ATB) treatment. Two main models based on the pulmonary instillation of PA embedded in agar or calcium-alginate beads are currently used. However, these two polymers used to prepare the beads have different properties; for example, agar is a neutral polysaccharide while alginate is anionic. We hypothesized that the effect of an ATB on PA entrapped in agar or calcium-alginate beads depends on its physicochemical properties, including charge, and concentration. To test this hypothesis, PAs were entrapped in agar or calcium-alginate beads dispersed in a growth medium containing either tobramycin (TOB), selected as a cationic ATB, or ciprofloxacin (CIP) selected as a neutral zwitterionic ATB. In vitro, time-kill curves evaluating the efficacy of ATBs over time were performed by measuring the light emitted by a bioluminescent PA for 42 h in the presence of ATB concentrations ranging from 0 to 100 times the MIC. In the presence of CIP, time-kill curves obtained with PA trapped in agar or calcium-alginate beads were comparable, whatever the CIP concentration used. In the presence of TOB, a clear difference was observed between the kill curves obtained with PA embedded in agar or calcium-alginate beads. While PA trapped within agar displayed the same susceptibility than the planktonic one, it was unresponsive to TOB for concentrations up to 1-fold MIC when trapped in calcium-alginate. At 10-fold the TOB's MIC, the luminescence emitted by PA01 in the agar beads was reduced by 95% after 40 h, whereas it returned to the same initial value for PA01 trapped in alginate-based beads. The reduction in TOB efficiency was even greater when alginate-based beads were dispersed in a mucus-simulating medium. These results show that the agar and alginate beads models can be interchangeable only for uncharged ATB, such as CIP, but not for cationic ATB, like TOB. In vitro experiments performed in this study could be a quick way to evaluate the effect of each model on a given ATB before performing animal experiments.

Topics: Agar; Alginates; Animals; Anti-Bacterial Agents; Ciprofloxacin; Disease Models, Animal; Lung; Pseudomonas aeruginosa; Pseudomonas Infections; Respiratory Tract Infections; Tobramycin

Murine models of acute and chronic lung infection have been used in studying Pseudomonas aeruginosa for assessing in vivo behavior and for monitoring of the host response. These models provide an important resource for studies of the initiation and maintenance of bacterial infection, identify bacterial genes essential for in vivo maintenance and for the development and testing of new therapies. The rat has been used extensively as a model of chronic lung infection, whereas the mouse has been a model of acute and chronic infection. Intratracheal administration of planktonic bacterial cells in the mouse provides a model of acute pneumonia. Bacteria enmeshed in agar beads can be used in the rat and mouse to reproduce the lung pathology of cystic fibrosis patients with advanced chronic pulmonary disease. Here, we describe the methods to assess virulence of P. aeruginosa using prototype and clinical strains in the Sprague-Dawley rat and the C57BL/6NCrlBR mouse by monitoring several measurable read-outs including weight loss, mortality, in vivo growth curves, the competitive index of infectivity, and the inflammatory response.

Topics: Acute Disease; Agar; Animals; Biological Assay; Chronic Disease; Colony Count, Microbial; Disease Models, Animal; Host-Pathogen Interactions; Inflammation; Kinetics; Lung; Male; Mice, Inbred C57BL; Pseudomonas aeruginosa; Pseudomonas Infections; Rats, Sprague-Dawley; Respiratory Tract Infections; Survival Analysis; Virulence

Phaeoacremonium parasiticum is an environmental dematiaceous mold rarely associated with human infections. We present here 2 cases of P. parasiticum invasive infections, including the first report of P. parasiticum respiratory tract infection, and 1 case of airway colonization, which all 3 strains of P. parasiticum were identified using agar block smear and ITS and β-tubulin gene sequencing. All 3 isolates grew initially as white to creamy, yeast-like colonies. After 21 days of incubation at 25 °C, 1 isolate remained light brown, atypical of P. parasiticum. Microscopic examination of agar block smear preparations of all 3 isolates showed thick-walled, medium brown conidiophores that were branched and slightly swollen at the base. The sequences of the ITS and β-tubulin genes of the 3 isolates were identical to those of P. parasiticum. Cases of P. parasiticum infections should be confirmed by a polyphasic approach using morphologic characterization and ITS and β-tubulin gene sequencing.

Topics: Adult; Agar; Aged; Ascomycota; Culture Media; DNA, Fungal; DNA, Ribosomal Spacer; Humans; Male; Microscopy; Molecular Sequence Data; Mycoses; Phylogeny; Respiratory Tract Infections; Sequence Analysis, DNA; Tubulin

Topics: Agar; Culture Media; Cystic Fibrosis; Diagnosis, Differential; Humans; Influenza, Human; Reagent Kits, Diagnostic; Respiratory Tract Infections

We sought to characterise a refined rat model of respiratory infection with P. aeruginosa over an acute time course and test the antibiotic ciprofloxacin.. Agar beads were prepared ± SPAN(®)80. Rats were inoculated with sterile agar beads or those containing 10(5) colony forming units (cfu) P. aeruginosa via intra-tracheal dosing. Bacterial load and inflammatory parameters were measured.. Differing concentrations of SPAN(®) 80 modified median agar bead diameter and reduced particle size distribution. Beads prepared with 0.01% v/v SPAN(®)80 were evaluated in vivo. A stable lung infection up to 7 days post infection was achieved and induced BALF neutrophilia 2 and 5 days post infection. Ciprofloxacin (50mg/kg) significantly attenuated infection without affecting the inflammatory parameters measured.. SPAN(®) 80 can control the particle size and lung distribution of agar beads and P. aeruginosa-embedded beads prepared with 0.01%v/v SPAN(®)80 can induce infection and inflammation over 7 days.

Topics: Acute Disease; Agar; Animals; Anti-Infective Agents; Bacterial Load; Bronchoalveolar Lavage Fluid; Ciprofloxacin; Disease Models, Animal; Hexoses; Leukocyte Count; Male; Microspheres; Neutrophils; Particle Size; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Rats, Sprague-Dawley; Respiratory Tract Infections; Time Factors; Treatment Outcome

The aim of this study was to establish the degree of comparability between the NCCLS broth microdilution and BSAC agar dilution MIC methods of antimicrobial susceptibility testing.. Six hundred and sixty-one clinical isolates of Streptococcus pneumoniae, 936 Haemophilus influenzae and 421 Moraxella catarrhalis, collected in the winter of 1999-2000 by 20 laboratories in the UK and Eire from patients with presumed community-acquired lower respiratory infections, were tested by the two methods. MIC agreement was defined as excellent (good) if results were within +/- 1 doubling dilution for > or =90% (> or =80%) of isolates and within +/- 2 doubling dilutions for > or =95%. Isolates were categorized as susceptible, intermediate or resistant using the breakpoints appropriate to the testing method.. MIC agreement was good or excellent in 27 of 36 organism-agent combinations. Agreement was less for M. catarrhalis than for other species, and lower in all three species for cefaclor and trimethoprim than for other antimicrobials. Discrepancies in categorization occurred only occasionally, and were generally explained by differences in breakpoints rather than in measured MICs. One exception was S. pneumoniae with penicillin. Despite excellent MIC agreement and identical breakpoints, 9% of these had minor discrepancies, mainly because 7% of isolates were found intermediate by the BSAC method but resistant by the NCCLS method.. There is generally very good agreement between the MICs obtained by the BSAC agar dilution and NCCLS broth microdilution methods in this population of isolates, comparable to the level of agreement achieved between different laboratories using a single method. Breakpoint differences contribute to most of the discrepancies in susceptibility categorization.

Topics: Agar; Anti-Bacterial Agents; Community-Acquired Infections; Culture Media; Haemophilus influenzae; Humans; Ireland; Microbial Sensitivity Tests; Moraxella catarrhalis; Population Surveillance; Reproducibility of Results; Respiratory Tract Infections; Streptococcus pneumoniae; United Kingdom

The purpose of this study was to examine the antibacterial effects of a wide variety of essential oils on major respiratory tract pathogens. The antibacterial activity of 14 essential oils and their major components was evaluated by agar-plate dilution assay under sealed conditions, with agar used as a stabilizer for homogeneous dispersion. Of the selected strains of four major bacteria causing respiratory tract infection, Haemophilus influenzae was most susceptible to the essential oils, followed by Streptococcus pneumoniae and Streptococcus pyogenes. Staphylococcus aureus was less susceptible. No cross-resistance was observed between penicillin-sensitive and penicillin-resistant S. pneumoniae. Escherichia coli, used as a control bacterium, showed the lowest susceptibility. Essential oils containing aldehyde or phenol as a major component showed the highest antibacterial activity, followed by the essential oils containing terpene alcohols. Other essential oils, containing terpene ketone, or ether, had much weaker activity, and an oil containing terpene hydrocarbon was inactive. Based on these findings, thyme (wild, red, and geraniol types), cinnamon bark, lemongrass, perilla, and peppermint oils were selected for further evaluation of their effects on respiratory tract infection.

Topics: Agar; Anti-Bacterial Agents; Bacteria; Bacteriological Techniques; Gram-Positive Cocci; Haemophilus influenzae; Humans; Microbial Sensitivity Tests; Oils, Volatile; Respiratory Tract Infections

A total of 258 respiratory tract specimens from patients with cystic fibrosis were inoculated onto nine different plated media, and the rates of recovery of potential pathogens were compared. Media included sheep blood agar, enriched chocolate agar, MacConkey agar for gram-negative bacilli, chocolate agar containing bacitracin for Haemophilus spp., bromcresol green agar for yeasts, cetrimide agar for Pseudomonas spp., sheep blood agar containing colistin and nalidixic acid for gram-positive cocci, mannitol salt agar for Staphylococcus aureus, and oxidation-fermentation agar containing 300 U of polymyxin B per ml and 2 U of bacitracin per ml (OF-PBL medium) for Pseudomonas cepacia. With two exceptions, all of these media proved useful in recovering potential pathogens from respiratory tract specimens from patients with cystic fibrosis. The two exceptions were cetrimide agar and colistin-nalidixic acid-supplemented sheep blood agar, which were found to be superfluous. In addition, the results of this study further delineated the prevalence of selected bacteria and fungi in respiratory tract secretions from patients with cystic fibrosis. In rank order of frequency of isolation, we recovered isolates of Pseudomonas aeruginosa, Haemophilus parainfluenzae, Candida albicans, S. aureus, Haemophilus influenzae, molds, members of the family Enterobacteriaceae, yeasts other than Candida albicans, miscellaneous gram-negative bacilli, beta-hemolytic streptococci, P. cepacia, and Streptococcus pneumoniae.

Topics: Agar; Bacteria; Bacteriological Techniques; Culture Media; Cystic Fibrosis; Humans; Respiratory Tract Infections

Sterile agar beads plus Pseudomonas aeruginosa injected intratracheally produced local infection in rats, similar to that described for the injection of agar beads containing the same pathogen. It is suggested that it is not necessary for P. aeruginosa to be inside the beads to induce lung infection.

Topics: Adhesiveness; Agar; Animals; Capsules; Lung; Pseudomonas Infections; Rats; Respiratory Tract Infections

Isolation of Haemophilus influenzae from specimens contaminated with upper respiratory tract microbial flora was attempted with three different media: enriched chocolate agar, chocolate agar plus vancomycin, and chocolate agar plus vancomycin, bacitracin, and clindamycin. Recovery rates of H. influenzae from 852 pediatric pharyngeal swab specimens were 6.0, 28.5, and 59.9%, respectively.

Topics: Adolescent; Agar; Child; Child, Preschool; Culture Media; Haemophilus Infections; Haemophilus influenzae; Humans; Infant; Pharyngitis; Pharynx; Respiratory Tract Infections

Topics: Adult; Agar; Animals; Bacitracin; Bronchiectasis; Cattle; Culture Media; Culture Techniques; Cystic Fibrosis; Haemophilus Infections; Haemophilus influenzae; Hemin; Humans; Respiratory Tract Infections; Sputum

A medium was investigated for transportation of Mycoplasma pulmonis pure cultures and swabs from animals suspected of having Mycoplasma pulmonis infections. The medium was developed because many culture specimens from animals carry an abundance of contaiminating bacteria masking in vitro growth of Mycoplasma pulmonis. Commonly occurring contaminants were identified, and their antibiotic sensitivities were quantified. The combination of carbenicillin, tribrissen and polymixin B was found to inhibit contaminating bacteria and allow Mycoplasma pulmonis to grow in the transport medium. Mycoplasma pulmonis survived under a wide range of temperatures for extended periods of time in the transport medium. Actual shipment of the medium containing Mycoplasma pulmonis demonstrated its value as a transport medium. The transport medium not only protected Mycoplasma pulmonis in transit but also was selective in promoting its growth in vitro.

Topics: Agar; Animals; Animals, Laboratory; Anti-Bacterial Agents; Bacteriological Techniques; Culture Media; Drug Resistance, Microbial; Mycoplasma; Mycoplasma Infections; Rats; Respiratory Tract Infections; Species Specificity; Temperature; Transportation

The immunological response of cattle exposed to moldy hay was examined by agar gel diffusion with standard farmer's lung hay antigens. A high incidence of precipitins against Micropolyspora faeni (60%) and moldy hay antigen (80%) was detected in exposed but apparently healthy cattle from a region with a high incidence of bovine farmer's lung. In comparison, in the plains, a low incidence area, we found only 1 animal of 164 harboring precipitins against M. faeni. We further observed that many animals from exposed populations lost their precipitins during pasturing and regained them during winter housing. Thirty-nine clinical cases of bovine farmer's lung ("Urner Pneumonie") were investigated serologically. Only 49% of these animals showed precipitins against M. faeni and 54% showed precipitins against moldy hay antigen. We discuss in this paper the probable causes of this apparent lack of immunological response.

Topics: Agar; Animals; Antigens, Fungal; Aspergillus; Cattle; Cattle Diseases; Farmer's Lung; Fungi; Immunodiffusion; Immunoelectrophoresis; Micromonospora; Precipitins; Respiratory Hypersensitivity; Respiratory Tract Infections; Seasons; Serologic Tests

A technique is described for estimating the number of potential respiratory infectious loci of aerosolized infectious bovine rhinotracheitis virus.

Topics: Aerosols; Agar; Air Microbiology; Antibody Formation; Bacteriological Techniques; Culture Techniques; Herpesvirus 1, Bovine; Methods; Respiratory Tract Infections

Topics: Agar; Animals; Bacitracin; Bacteriological Techniques; Culture Media; Haemophilus; Haemophilus influenzae; Horses; Humans; Rabbits; Respiratory Tract Infections

Topics: Agar; Bronchi; Bronchial Diseases; Chromatography; Cystic Fibrosis; Humans; Phenylacetates; Respiratory Tract Infections; Sputum; Staphylococcal Infections; Staphylococcus