ABSTRACT
The aim of this investigation was to determine the persistence of biofilm-associated antibiotic resistance developed by methicillin-sensitive Staphylococcus aureus (MSSA), of different capsular types, during biofilm formation. Because of superiority of the tissue culture plate (TCP) over the Congo Red Agar (CRA) method for measuring biofilm formation, it was used to determine the persistence of the antibiotic resistance developed by the isolates in biofilms. The antibiotic resistance was found to persist for 3-4 wk post-propagation as planktonic subcultures. Interestingly, some strains even developed resistance to vancomycin and/or teicoplanin. However, no association of either biofilm formation or persistent antibiotic resistance with the major capsular phenotype was observed. These observations highlight the potential significance of (a) determining the antibiograms of S. aureus subcultured from biofilms developed in vitro using the TCP method as well as from planktonic cultures for formulation of an optimal therapeutic strategy, and (b) continuing to identify predominant non-capsular antigens contributing to biofilm formation, regardless of the capsular phenotype for the development of an effective potentially broad-spectrum vaccine for prevention of bovine mastitis caused by S. aureus.
Subject(s)
Anti-Bacterial Agents/pharmacology , Biofilms/drug effects , Biofilms/growth & development , Drug Resistance, Bacterial , Mastitis, Bovine/microbiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/physiology , Animals , Australia , Bacterial Capsules/genetics , Bacterial Proteins , Cattle , Genotype , Microbial Sensitivity Tests , Polymerase Chain Reaction , Staphylococcus aureus/isolation & purificationABSTRACT
The concentration of Terramycin and Furazolidone residues in broiler meat following their subtherapeutic use in the ration of the birds were detected as 296 ng/g, 174 ng/g, 40 ng/g, 60 ng/g and 124 ng/ml in kidney, liver, thigh muscle, breast muscle and serum for Terramycin and 270 ng/g 160 ng/g and 88 ng/ml in kidney, liver and serum for Furazolidone. One week of withdrawal period from the antibiotic in feed/water was sufficient to render the meat free from residues.
Subject(s)
Animal Feed/adverse effects , Food Contamination/analysis , Furazolidone , Oxytetracycline/analysis , Poultry , Animals , Drug Residues/analysis , Humans , IndiaABSTRACT
OBJECTIVE: To assess if Staphylococcus aureus is transmitted between man and animals & vice-versa. METHODS: Staphylococcus aureus belonging to biotype C (bovine origin) were isolated from nares and hands of workers on six dairy farms of Assam and Meghalaya. The cows on the farms had a high rate of prevalence of mastitis caused by the same biotype of S. aureus. Three strains of S. aureus biotype A (human origin) were isolated from mastitis milk samples from cows on one of these farms, in which one of the workers was having cuteneous lesions (crusty abscess) and one strain of S. aureus biotype A was isolated from a swab sample collected from an abscess on the skin of the worker. RESULTS: It has been revealed that all the members of the workers family were suffering from a similar type of cuteneous infection, indicating that it was a case of impetigo. The antibiotic susceptibility pattern of all the three biotype A strains from bovine origin was identical to that of the biotype A strains isolated from the worker. The percentage of resistance to 12 commonly used therapeutic antimicrobial agents was higher among the biotype C strains from human origin than the biotype C strains from bovine origin. Several strains from cattle and human origins showed identical antimicrobial susceptibility patterns against the tested agents.
