For complicated infections, decreased susceptibility could compromise treatment with drugs from either antimicrobial class. 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 µg/mL or ciprofloxacin MIC > 0.12 µg/mL) and extended-spectrum cephalosporins (ceftiofur or ceftriaxone MIC > 2 µg/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 (S80I 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 1Typhimurium isolate contained bla SHV-12 ; the Mbandaka isolate contained bla SHV-30 . Nine Senftenberg isolates contained bla OXA-1 ; 1 contained bla OXA-9 . Further studies should address patient outcomes, risk factors, and resistance dissemination prevention strategies.
【저자키워드】 Research, drug resistance, microbial, cephalosporins, quinolones, Salmonella enterica, beta-lactamases, microbial sensititivity tests,