肺炎克雷伯菌荚膜血清型、毒力基因和耐药性研究

Study on capsular serotypes,virulence genes and drug resistance of Klebsiella pneumoniae

目的研究肺炎克雷伯菌(KPN)主要荚膜血清型、毒力基因的分布特点和细菌耐药特征,并初步探讨三者之间的相互关系。方法收集2019年1-9月该院临床分离的KPN,由DL-96Ⅱ细菌鉴定仪进行细菌鉴定和体外药敏试验;黏液丝试验检测黏液表型;聚合酶链式反应(PCR)法扩增6种主要荚膜血清型(K1、K2、K5、K20、K54和K57型)和6种毒力基因(rmpA、magA、wcaG、fimH、kfu和Aero)。结果93株KPN中6种荚膜血清型均有检出,分别为K2型(21.50%)、K1型(13.98%)、K57型(8.60%)、K54型(3.23%)、K20型(3.23%)和K5型(1.08%)。毒力基因中fimH构成比最高(96.80%),其次是rmpA(64.52%)和Aero(64.52%);6种毒力基因在13株K1型菌中全部都有检出;rmpA+fimH+Aero的基因组合最为多见(33.33%)。高黏液表型菌(HvKP)检出率为54.84%,非高黏液表型菌(cKP)为45.16%;6种荚膜血清型、毒力基因rmpA、Aero、wcaG在HvKP的检出率均明显高于cKP的检出率。细菌耐药方面,cKP的耐药情况较HvKP严重;多重耐药菌在黏液表型、荚膜血清型、rmpA、magA、wcaG、Aero的检出率明显低于敏感菌株。结论K2、K1、K57型是KPN常见的荚膜血清型,K1型携带的毒力基因最多;HvKP携带的荚膜血清型和毒力基因明显高于cKP,但其耐药率低于cKP;多重耐药菌携带的荚膜血清型和毒力基因明显低于敏感菌。

Objective To analyze the distribution of major capsular serotypes,virulence genes and bacterial resistance of Klebsiella pneumoniae(KPN),and preliminarily discuss the relationship among them.Methods KPN strains were collected from January to September 2019 in Zhenjiang Integrated Traditional Chinese and Western Medicine Hospital.The antibacterial susceptibility in vitro were identified by DL-96Ⅱbacteria identification instrument;mucus phenotype were detected by string test.Six major capsular serotypes(K1,K2,K5,K20,K54 and K57)and six virulence genes(rmpA,MagA,wcaG,fimH,kfu and aero)were amplified by PCR.Results Six kinds of capsular serotypes were all detected among 93 strains of KPN,which were K2(21.50%),K1(13.98%),K57(8.60%),K54(3.23%),K20(3.23%)and K5(1.08%).Among the virulence genes,the detection rates of fimH was the highest(96.80%),followed by rmpA(64.52%)and aero(64.52%);all six virulence genes were detected in 13 strains of K1 serotypes;and the most common gene combination was rmpA+fimH+Aero(33.33%).The detection rates of HvKP and cKP were 54.84%and 45.16%respectively.The detection rates of six capsular serotypes,rmpA,Aero and wcaG in HvKP were significantly higher than those in cKP.The antibacterial resistance of cKP was more serious than that of HvKP;the detection rate of multidrug-resistant bacteria in mucus phenotype,capsular serotype,rmpA,MagA,wcaG and Aero was significantly lower than that of sensitive strains.Conclusion K1/K2/K57 were the common capsular serotypes of KPN,and K1 serotype carries the most virulence genes.Capsular serotype and virulence genes carried by HvKP were significantly higher than those carried by cKP,but the antibacterial resistance rate is lower than that of cKP.The capsular serotypes and virulence genes carried by multidrug resistant bacteria were significantly lower than those of sensitive bacteria.