title: Molecular analysis of ciprofloxacin resistance among non-typhoidal Salmonella with reduced susceptibility to ciprofloxacin isolated from patients at a tertiary care hospital in Kuala Lumpur, Malaysia.
abstract: We investigated the prevalence of non-typhoidal Salmonella (NTS) with "reduced susceptibility to ciprofloxacin" (RS-Cip) (minimum inhibitory concentration [MIC], 0.12-1.0 μg/mL) as well as their resistance genes in 75 NTS isolates (53 from stool, 21 from blood, and 1 from urine) from patients at a tertiary care Malaysian hospital between January and December 2009. RS-Cip was detected in 24/75 (32.0%) isolates. Using the ciprofloxacin MIC interpretive criteria for Salmonella in the Clinical and Laboratory Standards Institute 2013 guidelines, 51/75 (68.0%) isolates were found to be sensitive, 22/75 (29.3%) were intermediate, and 2/75 (2.7%) were resistant to ciprofloxacin. The 24 isolates that were intermediate or resistant to ciprofloxacin were the same isolates categorized as having RS-Cip. Among the 23 tested isolates with RS-Cip, the qnrS gene was detected in 17/23 (73.9%) and single gyrA mutations were detected in 6/23 (26.1%) (Asp87Tyr [n = 3], Asp87Asn [n = 2], and Ser83Phe [n = 1]). A parC (Thr57Ser) mutation was detected in 13/23 (56.5%) isolates, coexisting with either a qnrS gene or a gyrA mutation. The high incidence of the qnrS gene among isolates with RS-Cip needs to be monitored because qnr genes can spread via plasmids and aid in the emergence of increased resistance levels.
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, University of Malaya.
authors.forename: Rina
authors.initials: R
authors.lastname: Karunakaran
authors.forename: Sun Tee
authors.initials: ST
authors.lastname: Tay
authors.forename: Fairuz Fadzilah
authors.initials: FF
authors.lastname: Rahim
authors.forename: Bee Bee
authors.initials: BB
authors.lastname: Lim
authors.forename: Savithri D
authors.initials: SD
authors.lastname: Puthucheary
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D008296:Malaysia; D008826:Microbial Sensitivity Tests; D012475:Salmonella / Q000187:drug effects* / Q000235:genetics*; D012480:Salmonella Infections / Q000382:microbiology*; D063128:Tertiary Health Care
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin