[Coproduction of qnrB and armA from extended-spectrum beta-lactamase-producing Klebsiella pneumoniae].
BACKGROUND
Multidrug-resistant Enterobacteriaceae is a worldwide problem. Although various resistance mechanisms have been recognized with increasing frequency, only a few cases of triple resistance of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae have been reported. This study was designed to evaluate the coexistence of qnr (qnrA, qnrB, and qnrS) and 16S rRNA methylase (armA, rmtA, rmtB, and rmtC) in ESBL-producing K. pneumoniae.


METHODS
We tested 44 isolates of ESBL-producing K. pneumoniae at Chungnam National University Hospital from March to September 2006. Antimicrobial susceptibilities were tested by broth microdilution method, and transconjugation test was performed using E. coli J53 with azide resistance. Search for qnr (qnrA, qnrB, and qnrS) and 16S rRNA methylase (armA, rmtA, rmtB, and rmtC) genes was conducted by PCR amplification, and the genotypes were determined by direct nucleotide sequence analysis of the amplified products. Epidemiologic study was performed by Enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR).


RESULTS
All ESBL-positive strains produced qnrB; however, armA was detected in 68.2%. The coproduction rate of qnrB and armA in ESBL-producing K. pneumoniae was 68.2%. Two types (A and B) were dominant in ERIC-PCR results.


CONCLUSIONS
K. pneumoniae producing qnrB, armA, and ESBL are spreading widely.
Kim
Moon Hee
MH
Department of Laboratory Medicine, Sun General Hospital, Daejeon, Korea.
Sung
Ji Youn
JY
Park
Jong Woo
JW
Kwon
Gye Cheol
GC
Koo
Sun Hoe
SH
D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008780:Methyltransferases / Q000096:biosynthesis / Q000235:genetics*; D001618:beta-Lactamases / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics*
D001426:Bacterial Proteins; C485385:Qnr protein, Klebsiella pneumoniae; D008780:Methyltransferases; C035181:rRNA (adenosine-O-2'-)methyltransferase; D001618:beta-Lactamases