title: Integron- and carbenicillinase-mediated reduced susceptibility to amoxicillin-clavulanic acid in isolates of multidrug-resistant Salmonella enterica serotype typhimurium DT104 from French patients.
abstract: Fifty-seven Salmonella enterica serotype Typhimurium (S. typhimurium) isolates were collected from human patients in two French hospitals, Hôpital Antoine Béclère (Clamart, France) and Hôpital Bicêtre (Le Kremlin-Bicêtre, France), between 1996 and 1997. Thirty of them (52 percent) were resistant to amino-, carbeni-, and ureidopenicillins, had reduced susceptibility to amoxicillin-clavulanic acid, were susceptible to cephalothin, and were resistant to sulfonamides, streptomycin, chloramphenicol, and tetracyclines. All these strains possessed a blaPSE-1-like gene and were of phage type DT104. Ten of them were studied in more detail, which revealed that blaPSE-1 is located on the variable region of a class 1 integron. This integron was found to be chromosomally located, as was another class 1 integron containing aadA2, a streptomycin-spectinomycin resistance gene. The reduced susceptibility to amoxicillin-clavulanic acid (and to ticarcillin-clavulanic acid) may result from the high level of hydrolysis of the beta-lactam rather than to the clavulanic acid resistance properties of PSE-1 in these clonally related S. typhimurium isolates.
authors.affiliation: Service de Bactériologie-Virologie, Hôpital de Bicêtre, 94275 Le Kremlin-Bicêtre, France.
authors.forename: L
authors.initials: L
authors.lastname: Poirel
authors.forename: M
authors.initials: M
authors.lastname: Guibert
authors.forename: S
authors.initials: S
authors.lastname: Bellais
authors.forename: T
authors.initials: T
authors.lastname: Naas
authors.forename: P
authors.initials: P
authors.lastname: Nordmann
mesh_terms: D019980:Amoxicillin-Potassium Clavulanate Combination / Q000494:pharmacology* / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D004352:Drug Resistance, Microbial / Q000235:genetics; D018432:Drug Resistance, Multiple / Q000235:genetics; D005602:France / Q000453:epidemiology; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D019426:Integrases / Q000235:genetics; D008826:Microbial Sensitivity Tests; D010405:Penicillinase / Q000235:genetics*; D012480:Salmonella Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D019980:Amoxicillin-Potassium Clavulanate Combination; D019426:Integrases; D010405:Penicillinase