Parts Of Shanxi Diarrhea Pathogens Distribution And Related To Purging E. Coli Virulence Genes

Objective: Diarrheal diseases caused by bacterial pathogens are a major problemworldwide,especially in developing countries. Diarrheal diseases due to the different DEC areand important public health problem in many parts of the world. The purpose of this study ismonitor the distribution of pathogenic bacteria from patients with diarrhea in shanxi area and toprovide reference for regional epidemiological study. The aims of this study are to evaluate theprevalence categories serotypes distribution of virulence factor genes of DEC isolated fromacute diarrheal cases in Shanxi region by polymerase chain reaction(PCR) methed targeting11virulence factor genes.Methods The pathogenic bacteria isolated from feces of patient with diarrhea in part of Shanxiwere cultured and identified to species,groups and serotypes with the biochemical andserological tests. Eleven targeted virulence-associated genes escV bfpB stx1A stx2A eltestIa estIb invE astA aggR pic are selected to molecular detect simultaneously fivecategories of diarrheagenic E.coli EPEC EHEC ETEC EIEC EAEC by multiplexpolymerase chain reaction.Samples were collected from patients with diarrhea in four cities(Yuci Changzhi Linfen Taiyuan) of Shanxi Province,China,from December2009toDecember2010.The specimens were cultured for E.coli and other pathogens by conventionalcultivation methods,E.coli strains were screened for DEC by multiplex PCR method.Results:1.Among152diarrheal etiologic agents isolated from288diarrheal cases in fourcities of Shanxi Province,84corresponded to diarrheagenic E.coli,indicating a high prevalenceamong the diarrheagenic population.DEC and Klebsiella pneumonia pathotypes were the mostof prevalent. The84diarrheagenic E.coli detected by mPCR,29(19.1) were EPEC,19(12.5)were ETEC,16(10.5) were EAEC,13were EHEC,7(4.6) were EIEC.2. Among288cases of acute diarrhea patients in Shanxi Province, pathogenic bacteria strainsof Jinzhong was separated the most area,followed by changzhi. Seasonal distribution wasmainly in summer and autumn,June to August as the peak of the disease.Pathogenic bacteriadistributed in patients with diarrhea of all age,but mainly in infant of two years old.Theprevalence of pathotypes were170male cases and118female cases in acute diarrhea patients.3.In84strains DEC,27strains(32.1) is positive by serum aggregation test,belonging to17species seroum type.EPEC serotypes belonging to7species,mainly serotypes were O128andO111.ETEC serotypes belonging to5species,mainly serotypes were O25.There were3different EIEC serotypes and1EHEC serotypes.EAEC not found serotypes.4. A total of9virulence-related gene were detected in84DEC expressing10patterns in whichmost prevalent genetype model were escV2428.6and elt1821.4.In27serotypedstrains,10strains carrying escV (37.0%),9strains carrying elt (33.3%),3strains carrying invE (11.1%).In57unclassified strains,14strains (24.6) to carry escV,10strains (17.5) to carryescV+stx2A,9strains (15.8) carry elt, eight strains (14.0) aggR carry. Several differentcombinations of the virulence markers were found among the EAEC isolates.The mostprevalent was aggR.Conclusions:1.Our study demonstrated high proportion of DEC(55.3) in Shanxi area and themain pathogen of acute diarrhea.There are five groups of DEC in this area.The most prevalentis EPEC,followed by ETEC and EAEC,EHEC and EIEC were rare.2. Pathogenic bacteria strains of Jinzhong was separated the most area from acute diarrheapatients in Shanxi Province,followed by changzhi. Seasonal distribution was mainly in summerand autumn,June to August as the peak of the disease.Pathogenic bacteria distributed in patientswith diarrhea of all age,but mainly in infant of two years old.The prevalence of pathotypes were170male cases and118female cases in acute diarrhea patients.3.There is higher serotypable rate (32.1) in this area and at least17O serogroups areobtained.There were some relations between the serum type and virulence genes.It is suggestedthat serogrouping methed are inadequate for the identification of DEC isolates.4.Our study also recognized the diversity of E.coli virulence-related gene in thesearea.Genetype patterns for both serotyped and unclassified serotype isolates were similar,withescV and elt are the most prevalent genetype model.