Antimicrobial resistance in clinical isolates of Salmonella enterica serotype Enteritidis: relationships between mutations conferring quinolone resistance, integrons, plasmids and genetic types.
In 481 clinical isolates of Salmonella enterica serotype Enteritidis collected from a Spanish region in 2000, 108, 83 and four isolates were resistant, respectively, to nalidixic acid, ampicillin or both. Nalidixic acid resistance was the result of DNA gyrase mutations involving the codons Asp-87 (97 isolates) and Ser-83 (15 isolates) of the gyrA gene; no mutations in parC were detected. In ampicillin-resistant strains, blaTEM genes located on plasmids and/or the chromosome were implicated. Five plasmids containing blaTEM1-like genes were identified, ranging from 7 to 100 kb, four of which were self-transferable; one of these contained a class 1 sul1 integron with an aadA1a gene cassette. This integron was also found on the chromosome of an isolate resistant to ampicillin, streptomycin and sulfadiazine. A relationship between a 40 kb self-transferable plasmid and strains of Salmonella Enteritidis phage type 6a with a distinctive RAPD profile was established.
Soto
Sara M
SM
Departamento de Biología Funcional, Area de Microbiología, Facultad de Medicina, Universidad de Oviedo, C/Julián Clavería 6, 33006 Oviedo, Spain.
González-Hevia
M Angeles
MA
Mendoza
M Carmen
MC
D000667:Ampicillin / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology; D027081:DNA Gyrase / Q000235:genetics; D004352:Drug Resistance, Microbial; D005243:Feces / Q000382:microbiology; D032023:Integrons / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D009268:Nalidixic Acid / Q000494:pharmacology; D010406:Penicillins / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics*; D011804:Quinolines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012480:Salmonella Infections / Q000188:drug therapy* / Q000235:genetics; D019779:Salmonella enterica / Q000187:drug effects* / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics
D000890:Anti-Infective Agents; D010406:Penicillins; D011804:Quinolines; D009268:Nalidixic Acid; D000667:Ampicillin; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1; D027081:DNA Gyrase