摘要
Abstract
Objective To investigate clinical distribution and antimicrobial resistance genes of CTX-M extended-spectrumβ-lactamases (ESBLs)- and Klebsiella pneumoniae carbapenemases (KPCs)-producing Escherichia coli (E.coli)isolated from patients with infection.Methods Multidrug-resistant E.coli (MDR-E.coli)isolated from clinical specimens in a hospital in 2011 -2012 were collected,minimal inhibitory concentrations (MICs)were detec-ted by micro-broth dilution method;ESBLs and KPC genes were amplified by polymerase chain reaction (PCR), CTX-M and KPC genotypes,as well as multilocus sequence types (MLST)were identified.Results Of 48 MDR-E. coli,45(93.75%)only produced ESBLs,44(91 .67%)carried bla CTX-M gene,20(41 .67%)of which were bla CTX-M-1 gene and 32(66.67%)were bla CTX-M-9 gene,8 (16.67%)carried both genes.The following subtypes were identified through gene sequencing:CTX-M-14(65.91 %,29/44),CTX-M-55(31 .82%,14/44),CTX-M-15(11 .36%,5/44), CTX-M-3(2.27%,1/44),CTX-M-24(2.27%,1/44),and CTX-M-65(2.27%,1/44).The detection rates of CTX-M-14+CTX-M-55,CTX-M-14+CTX-M-15,and CTX-M-55+CTX-M-65 were 11 .36% (5/44),4.55%(2/44), and 2.27%(1/44)respectively.PCR showed that 2 (4.17%)ESBLs +KPC-producing strains carried bla KPC and bla CTX-M genes,sequencing analysis showed that 1 was CTX-M-14 +KPC-2,and the other was CTX-M-3 +KPC-2.ST 131 (53.66%)was the main type of MLST,ST648,ST405,ST167,and ST1193 were also detected. Conclusion CTX-M-14,CTX-M-55 and CTX-M-15 are the most common genotypes of ESBLs-producing E.coli isolates,different subtypes exists,ST131 is the predominant MLST,KPC-2-producing isolate of E.coli has been detected.关键词
大肠埃希菌/超广谱β-内酰胺酶/KPC酶/CTX-M/多位点序列分析Key words
Escherichia coli/extended-spectrum β-lactamase/Klebsiella pneumoniae carbapenemase/KPC/CTX-M/multilocus sequence typing分类
医药卫生
