肠道内、外感染气单胞菌的菌种分布特征及毒力基因分析

摘要

目的 了解肠道内、外分离气单胞菌菌种分布及毒力基因谱的差异,探究该菌致病性与感染部位的关系.方法 收集2013年5月至2015年9月急性腹泻患者及肠道外标本来源的气单胞菌156株,采用PCR方法检测其18种毒力基因hlyA、aerA、act、alt、ast、aexT、ascV、aopP、ascF-G、gcat、tapA、fla、Ser、exu、ahyB、eprCAI、lip、laf,并统计分析肠道内、外来源气单胞菌毒力基因谱的差异.结果 156株气单胞菌中肠道内气单胞菌79株,以豚鼠气单胞菌为主(51.9％);肠道外气单胞菌77株,主要为嗜水气单胞菌(48.1％)和豚鼠气单胞菌(39.0％).gcat、act 、fla、ahyB、exu、lip基因在肠道内、外气单胞菌中的检出率较高(＞45.57％),而aeT、aopP、ascF-G、ascV则较低(＜20.78％);gcat、ahyB、laf ast、exu、lip、hlyA、aerA在肠道内气单胞菌中的检出率显著低于肠道外(P＜0.05);嗜水气单胞菌gcat、ahyB、exu、lip、eprCAI、hlyA在肠道外的检出率显著高于肠道内(P＜0.05);豚鼠气单胞菌lip、hlyA在肠道外的检出率显著高于肠道内(P＜0.05),而aopP反之;维氏气单胞菌毒力基因在肠道内、外的检出率差异无统计学意义.结论 肠道内、外气单胞菌感染的菌种分布及携带的毒力基因谱存在差异,临床需区别对待.%Objective To investigate the species distribution and the difference of virulence gene spectra of Aeromonas isolated from intestinal tract and extraintestinal body fluid,and the correlation of their pathogenicity with infection sites.Methods A total of 156 Aeromonas strains isolated from the fecal specimens of patients with acute diarrhea and extraintestinal specimens were collected during May 2013 and September 2015.Eighteen virulence genes in these strains,including hlyA,aerA,act,alt,ast,aexT,ascV,aopP,ascF-G,gcat,tapA,fla,Ser,exu,ahyB,eprCAl,lip and laf,were detected by polymerase chain reaction(PCR).Last,the differences of virulence gene spectra between intestinal and extraintestinal Aeromonas were analyzed.Results Among 156 Aeromonas strains,79 were from fecal specimens,and 77 from extraintestinal specimens.Aeromonas caviae(A.caviae,51.9％) was the most common species in the intestinal strains,while Aeromonas hydrophila(A.hydrophila,48.1％) and A.caviae(39.0％) were the main pathogens in extraintestinal infections.The most prevalent virulence genes in intestinal and extraintestinal Aeromonas were gcat,act,fla,ahyB,exu and lip (＞ 45.57 ％),while aexT,aopP,ascF-G and ascV were less frequently detected (＜ 20.78％).The detection rates of gcat,ahyB,laf,ast,exu,lip,hlyA and aerA genes in intestinal Aeromonas were significantly lower than those in extraintestinal isolates (P ＜ 0.05).The detection rates of gcat,ahyB,exu,lip,eprCAl and hlyA genes in extraintestinal A.hydrophila were significantly higher than those in intestinal A.hydrophila (P ＜ 0.05).The detection rates of lip and hlyA genes in extraintestinal A.caviae were significantly higher than those in intestinal A.caviae (P ＜ 0.05),while that of aopP gene was just the reverse.There was no significant difference in the detection rates of virulence genes between intestinal and extraintestinal Aeromonas veronii.Conclusion There are significant differences in the species distribution and virulence genes of Aeromonas isolated from intestinal and extraintestinal specimens,indicating that clinicians should treat them differentially.