Virulence genes and homology analysis of Klebsiella pneumoniae associated with pyogenic liver abscess / 临床检验杂志

ABSTRACT

Objective To investigate the distribution of hypervirulent capsular serotypes and virulence genes of Klebsiella pneumoniae associated with pyogenic liver abscess(PLA),and analyze the homology of strains.Methods Twelve strains of liver abscess-related Klebsiella pneumoniae were isolated in Wuxi Second People's Hospital during January 2016 and August 2017.Among them,five were also detected in blood samples.All the strains were performed the viscous thread test,and the hypervirulent capsular serotypes and main virulence genes were detected by PCR.The homology of the strains was analyzed by the multilocus sequence types(MLST) and pulsed-field gel electrophoresis(PFGE).Results The positive rate of the viscous thread test for 12 strains of liver abscess-related Klebsiella pneumoniae was 75％.Three kinds of hypervirulent capsular serotypes,including K1 (6/12,50％),K54(1/12,8.3％) and K57(5/12,41.7％),were detected.The positive rates of virulence genes,such as wcaG,rmpA,ureA,fimH,mrkD,uge,Aer and iroNB,were all 100％,while that of iucB was 83.3％.The cf29a gene was not found,and the magA,allS and kfuBC genes were only detected in K1 serotype strains.MLST found that ST23(4/12,33.3％) and ST25(3/12,25％) were main sequence types,and then were ST412(2/12,16.7％),ST1660(1/12,8.3％),ST1049(1/t2,8.3％) and ST11 (1/12,8.3％).PFGE showed that 12 strains of Klebsiella pneumoniae were divided into 8 types,and that only 3 strains of K1 serotype belong to the same clonotype.Conclusion All the isolated liver abscess-related Klebsiella pneumoniae strains are highly virulent.ST23 and ST25 are main sequence types,and ST1049 is first reported.PFGE results show genetic diversity,and Kl-type Klebsiella pneumoniae has a certain epidemic tendency.