title: Mechanisms of resistance to ampicillin, chloramphenicol and quinolones in multiresistant Salmonella typhimurium strains isolated from fish.
abstract: Mechanisms of antibiotic resistance and epidemiological relationships were investigated for five multiresistant strains of Salmonella typhimurium isolated from fish in India. Four strains showed resistance to nalidixic acid, chloramphenicol, tetracycline, co-trimoxazole, gentamicin and beta-lactam antibiotics. The remaining strain was susceptible to all beta-lactam antibiotics tested and to co-trimoxazole but resistant to the other antibiotics tested. Epidemiological analysis performed by REP-PCR showed that the five isolates belonged to the same clone. Resistance to nalidixic acid was related to a single mutation in the gyrA gene. Chloramphenicol resistance was related to the production of chloramphenicol acetyl-transferase. An OXA-1 beta-lactamase, located in an integron, was responsible for resistance to ampicillin. These results indicate the health hazard posed by the fact that S. typhimurium may acquire or develop several mechanisms of resistance to a variety of antibiotics, including quinolones, and can thus cause disease in humans which may be difficult to treat.
authors.affiliation: Department of Microbiology, IDIBAPS, Hospital Clinic, School of Medicine, University of Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Ruiz
authors.forename: L
authors.initials: L
authors.lastname: Capitano
authors.forename: L
authors.initials: L
authors.lastname: Nuñez
authors.forename: D
authors.initials: D
authors.lastname: Castro
authors.forename: J M
authors.initials: JM
authors.lastname: Sierra
authors.forename: M
authors.initials: M
authors.lastname: Hatha
authors.forename: J J
authors.initials: JJ
authors.lastname: Borrego
authors.forename: J
authors.initials: J
authors.lastname: Vila
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D000818:Animals; D002701:Chloramphenicol / Q000494:pharmacology*; D027081:DNA Gyrase; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D005399:Fishes / Q000382:microbiology*; D005839:Gentamicins / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009268:Nalidixic Acid / Q000494:pharmacology; D009582:Nitrofurantoin / Q000494:pharmacology; D016133:Polymerase Chain Reaction / Q000379:methods; D015363:Quinolones / Q000494:pharmacology*; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics; D013752:Tetracycline / Q000494:pharmacology; D014031:Tobramycin / Q000494:pharmacology
chemical_list: D005839:Gentamicins; D015363:Quinolones; D009268:Nalidixic Acid; D002701:Chloramphenicol; D000667:Ampicillin; D009582:Nitrofurantoin; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II; D013752:Tetracycline; D014031:Tobramycin