title: Increase in nalidixic acid resistance among non-Typhi Salmonella enterica isolates in the United States from 1996 to 2003.
abstract: Fluoroquinolones commonly are used to treat adult Salmonella infections. Fluoroquinolone treatment has failed for persons infected with nalidixic acid-resistant Salmonella. From 1996 to 2003, state public health laboratories forwarded 12,252 non-Typhi Salmonella enterica isolates to the Centers for Disease Control and Prevention for antimicrobial susceptibility testing; 203 (1.6%) of the isolates were nalidixic acid resistant, and 14 (7%) of those were ciprofloxacin resistant. Resistance to nalidixic acid significantly increased from 0.4% in 1996 to 2.3% in 2003. All ciprofloxacin-resistant isolates had at least one point mutation in the quinolone resistance determining region (QRDR) of gyrA and did not harbor qnr or have point mutations in the QRDR of gyrB, parC, or parE. Continued surveillance of antimicrobial resistance among non-Typhi S. enterica isolates is needed to mitigate the increasing prevalence of nalidixic acid resistance.
authors.affiliation: Centers for Disease Control and Prevention, Mailstop D63, 1600 Clifton Rd., Atlanta, GA 30333, USA.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Stevenson
authors.forename: Kathryn
authors.initials: K
authors.lastname: Gay
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Barrett
authors.forename: Felicita
authors.initials: F
authors.lastname: Medalla
authors.forename: Tom M
authors.initials: TM
authors.lastname: Chiller
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Angulo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D024841:Fluoroquinolones / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests; D009268:Nalidixic Acid / Q000494:pharmacology*; D017354:Point Mutation; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D018571:Sentinel Surveillance; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D009268:Nalidixic Acid; D002939:Ciprofloxacin