title: Human Salmonella and concurrent decreased susceptibility to quinolones and extended-spectrum cephalosporins.
abstract: The National Antimicrobial Resistance Monitoring System monitors susceptibility among Enterobacteriaceae in humans in the United States. We studied isolates exhibiting decreased susceptibility to quinolones (nalidixic acid MIC >32 microg/mL or ciprofloxacin MIC > or =0.12 microg/mL) and extended-spectrum cephalosporins (ceftiofur or ceftriaxone MIC > or =2 microg/mL) during 1996-2004. Of non-Typhi Salmonella, 0.19% (27/14,043) met these criteria: 11 Senftenberg; 6 Typhimurium; 3 Newport; 2 Enteridis; and 1 each Agona, Haifa, Mbandaka, Saintpaul, and Uganda. Twenty-six isolates had gyrA mutations (11 at codon 83 only, 3 at codon 87 only, 12 at both). All Senftenberg isolates had parC mutations (S801 and T57S); 6 others had the T57S mutation. The Mbandaka isolate contained qnrB2. Eight isolates contained bla(CMY-2); 1 Senftenberg contained bla(CMY-23). One Senftenberg and 1 Typhimurium isolate contained bla(SHV-12); the Mbandaka isolate contained bla(SHV-30). Nine Senftenberg isolates contained bla(OXA-1) contained bla(OXA-9). Further studies should address patient outcomes, risk factors, and resistance dissemination prevention strategies.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. zyr3@cdc.gov
authors.forename: Jean M
authors.initials: JM
authors.lastname: Whichard
authors.forename: Kathryn
authors.initials: K
authors.lastname: Gay
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Stevenson
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Joyce
authors.forename: Kara L
authors.initials: KL
authors.lastname: Cooper
authors.forename: Michael
authors.initials: M
authors.lastname: Omondi
authors.forename: Felicita
authors.initials: F
authors.lastname: Medalla
authors.forename: George A
authors.initials: GA
authors.lastname: Jacoby
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Barrett
mesh_terms: D018550:Cephalosporin Resistance; D002511:Cephalosporins / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D006801:Humans; D007525:Isoelectric Focusing; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D015363:Quinolones / Q000494:pharmacology*; D012475:Salmonella / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology*; D014481:United States / Q000453:epidemiology
chemical_list: D002511:Cephalosporins; D015363:Quinolones