Prevalence of plasmid-mediated quinolone resistance and its association with extended-spectrum beta-lactamase and AmpC beta-lactamase in Enterobacteriaceae

• Published in: Taehan Chindan Kŏmsa Ŭihakhoe chi Vol. 31; no. 4; pp. 257 - 264
• Main Authors: Jeong, Haeng Soon, Bae, Il Kwon, Shin, Jeong Hwan, Jung, Hee Jung, Kim, Si Hyun, Lee, Ja Young, Oh, Seung Hwan, Kim, Hye Ran, Chang, Chulhun Ludgerus, Kho, Weon-Gyu, Lee, Jeong Nyeo
• Format: Journal Article
• Language: English
• Published: Korea (South) The Korean Society for Laboratory Medicine 01.10.2011
• Subjects: Anti-Bacterial Agents - pharmacology; Bacterial Proteins - biosynthesis; Bacterial Proteins - genetics; beta-Lactamases - biosynthesis; beta-Lactamases - genetics; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Drug Resistance, Bacterial - genetics; Enterobacteriaceae - enzymology; Enterobacteriaceae - genetics; Enterobacteriaceae - isolation & purification; Enterobacteriaceae Infections - microbiology; Genetic Variation; Hospitals, University; Humans; Microbial Sensitivity Tests; Original; Plasmids - genetics; Plasmids - metabolism; Quinolones - pharmacology; Beta-lactamase; Quinolone; Qnr; Enterobacteriaceae
• ISSN: 1598-6535
• DOI: 10.3343/kjlm.2011.31.4.257

We investigated the prevalence of plasmid-mediated quinolone resistance and its association with extended-spectrum beta-lactamase (ESBL) and AmpC beta-lactamase in Enterobacteriaceae. A total of 347 non-duplicated isolates of Enterobacteriaceae were collected between August and October 2006 from 2 hospitals. Qnr determinant screening was conducted using PCR amplification, and all positive results were confirmed by direct sequencing. Qnr-positive strains were determined on the basis of the presence of ESBL and AmpC beta-lactamase genes. The qnr gene was detected in 47 of 347 clinical Enterobacteriaceae isolates. Among the 47 qnr-positive strains, Klebsiella pneumoniae (N=29) was the most common, followed by Escherichia coli (N=6), Enterobacter cloacae (N=6), Citrobacter freundii (N=5), and Enterobacter aerogenes (N=1). These isolates were identified as qnrA1 (N=6), 8 qnrB subtypes (N=40), and qnrS1 (N=1). At least 1 ESBL was detected in 38 of the 47 qnr-positive strains. Qnr-positive strains also showed high positive rates of ESBL or AmpC beta-lactamase, such as TEM, SHV, CTX-M, and DHA. DHA-1 was detected in 23 of 47 qnr-positive strains, and this was co-produced with 1 qnrA1 and 22 qnrB4. Strains harboring MIR-1T and CMY were also detected among the qnr-positive strains. Antimicrobial-resistance rates of qnr-positive strains to ciprofloxacin, levofloxacin, norfloxacin, nalidixic acid, and moxifloxacin were 51.1%, 46.8%, 46.8%, 74.5%, and 53.2%, respectively. The qnr genes were highly prevalent in Enterobacteriaceae, primarily the qnrB subtypes. They were closely associated with EBSL and AmpC beta-lactamase.