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目的研究福建省非典型肠致病性大肠埃希菌(aEPEC)菌株的毒力基因特征和菌株间的遗传相似度;结合菌株的背景资料分析不同的分子特征对aEPEC流行的影响。方法运用PCR技术进行系列的相关毒力基因扩增;同时运用脉冲场凝胶电泳分子分型技术,对福建省2010-2012年分离的aEPEC菌株进行脉冲场凝胶电泳(PFGE)分子分型。结果分离30株实验菌株毒力基因的检测呈阳性的分别为:b112153.3%(16),yiaA36.7%(11),set/ent、nleB、nleE均为30%(9),lpfAR141 23.3%(7),efa/lifA20%(6),ehxA3.33%(1);其余毒力基因均未检出;93.3%(28)菌株不同程度地携带有相关的毒力因子。29株菌按照100%的相似度分为15个PFGE型别(P1-P15);其中存在4组不同的PFGE簇(I-Ⅳ),相同PFGE簇的病例在发病的时间和地区上有聚集性,同时相同簇内菌株的毒力基因谱也表现相同。结论 b1121、yiaA和EHEC毒力岛OI-122相关基因(efa1/lifA,nleB,nleE,set/ent)在福建省aEPEC菌株中携带率较高。非典型肠致病性大肠埃希菌的毒力谱表现为多样性,基因组也呈现遗传多态性;同时PFGE分析发现福建省存在由aEPEC新发病原菌引起的聚集性病例。
OBJECTIVE: To study the virulence genes and the genetic similarity among strains of atypical enteropathogenic Escherichia coli (aEPEC) in Fujian Province. The effects of different molecular characteristics on the epidemiology of aEPEC were analyzed with the background data of strains. Methods A series of related virulence genes were amplified by PCR. Meanwhile, pulsed-field gel electrophoresis (PFGE) molecular typing was performed on aEPEC isolates from 2010 to 2012 in Fujian Province. Results The virulence genes of 30 isolates were b112153.3% (16), yiaA36.7% (11), set / ent, nleB and nleE were all 30% (9), lpfAR141 23.3 (7), efa / lifA20% (6) and ehxA3.33% (1), respectively. No other virulence genes were detected; 93.3% (28) strains carried virulence factors to varying degrees. 29 strains were divided into 15 PFGE types (P1-P15) according to 100% similarity. There were 4 groups of different PFGE clusters (I-IV). Clusters of the same PFGE cluster accumulated at the time and place of onset While the virulence gene profiles of the same cluster strains also behaved the same. Conclusion The oI-122-associated genes (efa1 / lifA, nleB, nleE, set / ent) in the virulence island of b1121, yiaA and EHEC are higher in aEPEC strains in Fujian Province. The virulence spectrum of atypical enteric pathogenic Escherichia coli showed diversity and the genome also showed genetic polymorphism. At the same time PFGE analysis found that Fujian province had clustered cases caused by new pathogens of aEPEC.