Emergence of novel variants of gyrA, parC, qnrS genes in multi-drug resistant Klebsiella caused pneumonia / 中华流行病学杂志

ABSTRACT

Objective To investigate the resistant mechanism of quinolones on multi-drug resistant Klebsiella caused pneumonia(MDR-KPN).Methods From August 2008 to May 2010,47 strains of MDR-KPN were collected from 6 hospitals in Hangzhou and Huzhou in Zhejiang province in China.Drug target genes to quinolones (gyrA,parC) and quinolone-resistance genes mediated by mobile genetic elements [qnrA,qnrB,qnrS,aac (6')-Ⅰ b-cr,qepA] were analyzed by PCR and verified by DNA sequencing.Results Positive results were found in 47 strains of MDR-KPN,43 strains (91.5％) of gyrA mutation,40 strains(85.1％) ofparC mutation,3 strains (6.4％) of qnrB2,1 strain (2.1％) ofqnrB 4,8 strains (17.0％) ofqnrS 1,5 strains (10.6％) of qnrS 4,2 strains (4.3％)of aac (6')-Ⅰ b-cr respectively.Moreover,5 novel variants of gyrA (GenBank accession numberJN811952,JN811953,JN811954,JN811955,JN811956),5 novel variants of parC (GenBank accession numberJN817432,JN817433,JN817434,JN817435,JN817436)were also identified.In addition,qnrS4 (GenBank accession numberJN836269) appeared to be the novel variants of qnrS.Conclusion Quinolone-resistance-determining region played a key role on the resistance to quinolones in this group of MDR-KPN,and quinolone-resistance genes mediated by mobile genetic elements [qnrB2,qnrB4,qnrS1,qnrS4,aac (6')-Ⅰ b-cr] showed positive in some parts of the strains.This was the first report on emergence of qnrS4 in the world.