A novel Klebsiella pneumoniae carbapenemase variant,KPC-12,in a Klebsiella pneumoniae clinical isolate from China

【作者】 胡庆丰； 魏取好； 吕火祥； 吴秀萍； 沈蓓琼； 周永列；

【机构】 浙江省人民医院检验中心；

【摘要】 <正>Objective:To report a novel Klebsiella pneumoniae carbapenemase variant,termed KPC-12, in a Klebsiella pneumoniae clinical isolate ZJ10620 from China.Methods:0 -lactamase genes were screened by PCR with specific primers designed to sequences of known 3 -lactamase genes,including blaIMP,blaVIM, blaSME,blaKPC,blalMI,blaGES,blaVEB,blaCTX-M,blaTEM and blaNDM.The flanking sequences of blaKPC-12 gene were amplified by PCR and sequenced.Sequences of representative blaKPC genes were retrieved from GenBank and aligned,then the phylogenetic tree was constructed to to analyse the evolutionary relationship of the novel blaKPC gene with other blaKPC genes.Conjugation experiment combined with Southern hybridization were used to identify the genetic location and transferable of the new blaKPC gene. Results:The sequence of blaKPC-12 was 99%identical to blaKPC-2,with only single-nucleotide difference from it.This single-nucleotide mutation was in the position that different from all othe existed mutation positions of KPC genes and resulted in an amino acid change from a Leu to Met.The phylogenetic analysis indicated that blaKPC-12 is mostly related to blaKPC-2 and clustered together with blaKPC-11.blaKPC-12 has the same genetic environment to that of blaKPC-2.Conjugation experiments successfully transferred a plasmid from clinical isolate K.pneumoniae ZJ 10620 to the recipient E.coli J53.Apart from blaKPC-12,another twoβ-lactamase genes,blaTEM and blaCTX-M were also located on this plasmid and transfer along with it. Conclusions:A new blaKPC variant,termed blaKPC-12 was discovered in a clinical K.pneumoniae.The mutated position was different from all othe existed mutation positions of KPC genes.Whether this amino acid change can impact the kinetic propertie of KPC-12 remained to be determined.更多还原

【Abstract】 Objective:To report a novel Klebsiella pneumoniae carbapenemase variant,termed KPC-12, in a Klebsiella pneumoniae clinical isolate ZJ10620 from China.Methods:0 -lactamase genes were screened by PCR with specific primers designed to sequences of known 3 -lactamase genes,including blaIMP,blaVIM, blaSME,blaKPC,blalMI,blaGES,blaVEB,blaCTX-M,blaTEM and blaNDM.The flanking sequences of blaKPC-12 gene were amplified by PCR and sequenced.Sequences of representative blaKPC genes were retrieved from GenBank and aligned,then the phylogenetic tree was constructed to to analyse the evolutionary relationship of the novel blaKPC gene with other blaKPC genes.Conjugation experiment combined with Southern hybridization were used to identify the genetic location and transferable of the new blaKPC gene. Results:The sequence of blaKPC-12 was 99%identical to blaKPC-2,with only single-nucleotide difference from it.This single-nucleotide mutation was in the position that different from all othe existed mutation positions of KPC genes and resulted in an amino acid change from a Leu to Met.The phylogenetic analysis indicated that blaKPC-12 is mostly related to blaKPC-2 and clustered together with blaKPC-11.blaKPC-12 has the same genetic environment to that of blaKPC-2.Conjugation experiments successfully transferred a plasmid from clinical isolate K.pneumoniae ZJ 10620 to the recipient E.coli J53.Apart from blaKPC-12,another twoβ-lactamase genes,blaTEM and blaCTX-M were also located on this plasmid and transfer along with it. Conclusions:A new blaKPC variant,termed blaKPC-12 was discovered in a clinical K.pneumoniae.The mutated position was different from all othe existed mutation positions of KPC genes.Whether this amino acid change can impact the kinetic propertie of KPC-12 remained to be determined.更多还原