肺炎克雷伯菌中pks基因岛与毒力基因和生物膜形成的关系

Relationship of pks gene islands with virulence genes and biofilm formation in Klebsiella pneumoniae

目的研究肺炎克雷伯菌(Klebsiella pneumoniae,Kp)的pks基因岛与毒力基因、荚膜血清型和生物膜形成的关系,并测定其高黏液(hypermucoviscous,HM)表型和生物膜形成情况。方法收集福建医科大学附属第一医院临床标本分离的113株肺炎克雷伯菌株。根据pks基因岛存在与否分为pks^(+)组和pks^(-)组。采用拉丝试验检测高黏液表型。PCR扩增检测5种毒力基因(peg-344、rmpA、rmpA2、iucA、iroB)和6种常见荚膜血清型(K1、K2、K5、K20、K54、K57),利用微孔板法检测生物膜的形成情况。采用SPSS21.0软件进行统计分析,以P<0.05为差异具有统计学意义。结果113株临床分离的肺炎克雷伯菌株中,共检出46株pks^(+)肺炎克雷伯菌株和67株pks^(-)肺炎克雷伯菌株。pks^(+)组HM表型检出率为87.0%(40/46),高于pks^(-)组的检出率43.3%(29/67),差异有统计学意义(χ^(2)=21.879,P<0.001);pks^(+)组毒力基因(peg-344、rmpA、rmpA2、iucA、iroB)和血清型基因(K1型)的检出率均高于pks^(-)组,差异有统计学意义(P<0.05);且pks^(+)组菌株生物膜形成能力高于pks^(-)组(P<0.05)。结论携带有pks基因岛的肺炎克雷伯菌更多具有HM表型,血清型以K1型为主,菌株中peg-344、rmpA、rmpA2、iucA和iroB基因携带率较高,且生物膜形成能力较强。

Objective To investigate the relationship of pks gene islands with virulence genes,capsular serotypes and biofilm formation in Klebsiella pneumoniae(Kp).Methods A total of 113 Kp clinical isolates were collected in the First Affiliated Hospital of Fujian Medical University and divided into two groups based on the presence of pks gene islands:pks^(+)and pks^(-)groups.The hypermucoviscous(HM)phenotype was detected by string test.Five virulence genes(peg-344,rmpA,rmpA2,iucA,iroB)and six common capsular serotypes(K1,K2,K5,K20,K54,K57)were detected by polymerase chain reaction(PCR).The biofilm formation ability was measured by crystal violet staining.Results Among the 113 Kp isolates,46 were pks^(+)strains and 67 were pks^(-)strains.The detection rate of HM phenotype was higher in the pks^(+)group than in the pks^(-)group[87.0%(40/46)vs 43.3%(29/67)].The detection rates of virulence genes(peg-344,rmpA,rmpA2,iucA,iroB)and K1 serotype in the pks^(+)group were also higher than those in the pks^(-)group(P<0.05).The biofilm formation ability of the pks^(+)strains was higher than the pks^(-)strains(P<0.05).Conclusions Kp strains carrying pks gene islands were likely to display a HM phenotype and mainly belonged to the K1 serotype.Most of the pks^(+)Kp strains carried the virulence genes of peg-344,rmpA,rmpA2,iucA and iroB,and had a greater ability to form biofilms.