title: Plasmid-mediated quinolone resistance in non-Typhi serotypes of Salmonella enterica.
abstract: BACKGROUND
  Serious infections with Salmonella species are often treated with fluoroquinolones or extended-spectrum beta-lactams. Increasingly recognized in Enterobacteriaceae, plasmid-mediated quinolone resistance is encoded by qnr genes. Here, we report the presence of qnr variants in human isolates of non-Typhi serotypes of Salmonella enterica (hereafter referred to as non-Typhi Salmonella) from the United States National Antimicrobial Resistance Monitoring System for Enteric Bacteria.
  
  
  METHODS
  All non-Typhi Salmonella specimens from the United States National Antimicrobial Resistance Monitoring System for Enteric Bacteria collected from 1996 to 2003 with ciprofloxacin minimum inhibitory concentrations > or = 0.06 microg/mL (233 specimens) and a subset with minimum inhibitory concentrations < or = 0.03 microg/mL (102 specimens) were screened for all known qnr genes (A, B, and S) by polymerase chain reaction. For isolates with positive results, qnr and quinolone resistance-determining region sequences were determined. Plasmids containing qnr genes were characterized by conjugation or transformation.
  
  
  RESULTS
  Conjugative plasmids harboring qnrB variants were detected in 7 Salmonella enterica serotype Berta isolates and 1 Salmonella enterica serotype Mbandaka isolate. The S. Mbandaka plasmid also had an extended-spectrum beta -lactamase. Variants of qnrS on nonconjugative plasmids were detected in isolates of Salmonella enterica serotype Anatum and Salmonella enterica serotype Bovismorbificans.
  
  
  CONCLUSIONS
  Plasmid-mediated quinolone resistance appears to be widely distributed, though it is still uncommon in non-Typhi Salmonella isolates from the United States, including strains that are quinolone susceptible by the criteria of the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards). The presence of this gene in non-Typhi Salmonella that causes infection in humans suggests potential for spread through the food supply, which is a public health concern.
authors.affiliation: Atlanta Research and Education Foundation, Atlanta, GA, USA. kgay@cdc.gov
authors.forename: Kathryn
authors.initials: K
authors.lastname: Gay
authors.forename: Ari
authors.initials: A
authors.lastname: Robicsek
authors.forename: Jacob
authors.initials: J
authors.lastname: Strahilevitz
authors.forename: Chi Hye
authors.initials: CH
authors.lastname: Park
authors.forename: George
authors.initials: G
authors.lastname: Jacoby
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: David C
authors.initials: DC
authors.lastname: Hooper
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents; D002648:Child; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics*; D015363:Quinolones; D019779:Salmonella enterica / Q000145:classification*; D012703:Serotyping
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones