[Characterization of qnr gene for plasmid-mediated quionlone resistance].
OBJECTIVE
To explore the distribution of qnr gene and broad spectrum p-lactamase (ESBLs) gene in gram-negative bacteria which were isolated from our hospital patients.


METHODS
qnr gene in nonrepetitive 129 isolates of Escherichia coli, 10 isolates of Enterobacter cloacac and 29 isolates of K. pneunoniae were detected by polymerase chain reaction (PCR). For qnr gene positive strains, int I, SHV-1, TEM-1, CTX-M, OXA-I , OXA-II , OXA-III, DHA and EBC genes were examined. Plasmid conjugatable test was applied to examine whether qnr gene was located in conjugate plasmid and ERIC-PCR was carried out for DNA homologous analysis. ESBLs detection (according to phenotypic confirmatory test based on National Committee for Clinical Laboratory Standards criteria) and susceptibility test to 16 antibiotics were also performed.


RESULTS
qnr gene was found in 6 clinical isolates including 5 strain of E. coli and one strain of E. cloacac, but qnr gene was undetectable in K. pneunoniae isolates. The 6 clinical isolates were suspectible to imipenem but resistance to some other drugs while only 2 isolates of E. coli were susceptible to quinolone. Among the 6 qnr gene-positive strains, all of them belonged to I type integron-positive isolates, 4 isolates of them were TEM-1 producing strains,with only one isolate was OXA-III gene producing strain, and 2 isolates of them were EBC producing strains. Most of them were with 2 ESBLs gene if not more. qnr gene was on transferable plasmids which could be disseminated by clone.


CONCLUSIONS
In Wuhan city, the prevalence of qnr was confirmed. qnr gene were found with some ESBLs gene in the same strains, and qnr gene in suspect strains. The transmission of qnr gene producing strains could be mediated by transferable plasmids or clone, forcing us to make intensive investigation and take effective control measures.
Li
Cong-Rong
CR
Department of Clinical Laboratory, Renmin Hospital, Wuhan University, Wuhan 430060, China.
Lv
Xia
X
Luo
Shao-Feng
SF
Huang
Jun
J
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016972:Enterobacter cloacae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D029968:Escherichia coli Proteins / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D015363:Quinolones / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C485384:Qnr protein, E coli; C485385:Qnr protein, Klebsiella pneumoniae; D015363:Quinolones; D015378:Imipenem; D001618:beta-Lactamases