4株单核细胞增生李斯特菌分子特征分析

Research of molecular characteristics of four Listeria monocytogenes

目的分析4株临床分离单核细胞增生李斯特菌菌株分子特征。方法收集2018—2019年4株临床分离单核细胞增生李斯特菌菌株,用纸片扩散法检测菌株的药物敏感性;分别用PCR和多重PCR方法进行李斯特菌毒力岛(LIPI-1)、inlA、inlB基因扩增和血清分型;用多位点序列分型(MLST)和脉冲场凝胶电泳(PFGE)进行分子分型。结果4株单核细胞增生李斯特菌分为1/2a-3a和1/2b-3b-72种血清型且对青霉素、氨苄西林等10种抗菌药物敏感;所有分离株均携带李斯特菌毒力岛LIPI-1(prfA、actA、plcB、plcA、hly、hly2、mpl)和inlA、inlB基因;PFGE和MLST将4株菌分为4个不同的脉冲场凝胶电泳分型和ST型,包括ST121、ST619、ST621以及1株新型ST1474。结论4株单核细胞增生李斯特菌ST型菌株均为江苏地区首次检出,菌株的致病力与其携带的毒力基因有关。

Objective To analyze the molecular characteristics of four Listeria monocytogenes isolates.Methods Four clinical Listeria monocytogenes isolates were collected from 2018 to 2019.Their antimicrobial susceptibilities were detected by disk diffusion method.Listeria pathogenicity island 1(LIPI-1),inlA and inlB genes were detected by PCR,and serotype associated genes were detected by multiple PCR.The molecular typing of the four isolates was detected by multi-locus sequence typing(MLST)and pulsed field gel electrophoresis(PFGE).Results The four Listeria monocytogenes isolates were divided into two serotypes:1/2a-3a(n=2)and 1/2b-3b-7(n=2),and identified as sensitive to 10 antibiotics including penicillin and ampicillin etc.All the four isolates carried LIPI-1(prfA,actA,plcB,plcA,hly,hly2 and mpl),inlA and inlB genes.The 4 isolates were divided into 4 different pulsed field gel electrophoresis types(PTs)and sequence types(STs)by PFGE and MLST,including ST121,ST619,ST621 and a novel type ST1474.Conclusion The STs of all the four Listeria monocytogenes isolates were reported firstly in Jiangsu province.The pathogenicity of these isolates may relate to their carrying virulence genes.