S-Space College of Medicine/School of Medicine (의과대학/대학원) Laboratory Medicine (검사의학전공) Journal Papers (저널논문_검사의학전공)
Prevalence of Plasmid-Mediated Quinolone Resistance Determinants over a 9-Year Period
- Kim, Hong Bin; Park, Chi Hye; Kim, Chung Jong; Kim, Eui-Chong; Hooper, David C.; Jacoby, George A.
- Issue Date
- AMER SOC MICROBIOLOGY
- ANTIMICROBIAL AGENTS AND CHEMOTHERAPY; Vol.53 2; 639-645
- Recently, several plasmid-mediated quinolone resistance (PMQR) genes conferring low levels of quinolone resistance have been discovered. To evaluate the temporal change in the prevalence of PMQR genes over a decade in a tertiary hospital in the Republic of Korea, we selected every fifth isolate of Escherichia coli and Klebsiella pneumoniae and every third isolate of Enterobacter cloacae between 1998 and 2001 and between 2005 and 2006 from a collection of blood isolates. Six PMQR genes [qnrA, qnrB, qnrC, qnrS, aac(6`)-Ib-cr, and qepA] were screened by multiplex PCR and then confirmed by direct sequencing, and the aac(6`)-Ib-positive PCR products were digested with BtsCI to identify the aac(6`)-Ib-cr variant. Of 461 isolates, 37 (8%) had one of the six PMQR genes; 13 (5%) of 261 E. coli strains, 13 (10%) of 135 K. pneumoniae strains, and 11 (17%) of 65 E. cloacae strains. qnrB was the most common PMQR gene and was found as early as 1998, whereas qnrS, aac(6`)-Ib-cr, and qepA emerged after 2000. None of the isolates carried qnrA or qnrC. Ciprofloxacin resistance increased over time (P < 0.001), and the overall prevalence of PMQR genes tended to increase (P = 0.20). PMQR-positive isolates had significantly higher ciprofloxacin resistance and multidrug resistance rates (P = 0.005 and P < 0.001, respectively). The increasing frequency of ciprofloxacin resistance in Enterobacteriaceae was associated with an increasing prevalence of PMQR genes, and this change involved an increase in the diversity of the PMQR genes and also an increase in the prevalence of the mutations in gyrA, parC, or both in PMQR-positive strains but not PMQR-negative strains.
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