title: Epidemiological survey on Escherichia coli O157 in Chongqing and Three-Gorge Reservoir Areas of China.
abstract: Prevalence, presence of virulence and adherence associated genes, genetic diversity, biochemical characteristics, and antibiotic susceptibility were determined for Escherichia coli O157 isolated over 4 months in Chongqing city and Three-Gorge Reservoir Areas. 11 isolates of E. coli O157 were isolated from 1504 samples and 7 of them are O157:H7 and 4 are O157:H? All O157:H7 isolates had eaeA, ehxA, EspA and Tccp genes, but did not have stx1 and stx2. All O157:H? isolates did not have stx1, stx2, eaeA, ehxA, EspA and Tccp genes except for the isolate obtained from Yunyang county which had stx1. When eaeA and ehxA presented in isolates were digested by restriction enzymes, the numbers and the sizes of the segments were the same as the control E. coli O157 strains. This suggests that eaeA and ehxA exhibit poor polymorphism. Most E. coli O157 isolates showed identical biochemical activities to the standard strains for sorbitol and rhamnose, and all E. coli O157:H7 obtained from feces at the same dairy cattle farm had similar biochemical characteristics. Antibiotic susceptibility demonstrated resistance of the isolates to penicillin, ampicillin, bacitracin, cefuroxime, erythromycin, gentamycin and tetracycline, indicating the isolates obtained in this study had a multi-drug resistance.
authors.affiliation: Key Laboratory of Grazing and Domestic Grazing Animals of Chongqing, College of Animal Science and Technology, University of Southwest, Chongqing 400715, China. haojuwang63@yahoo.com.cn
authors.forename: Haoju
authors.initials: H
authors.lastname: Wang
authors.forename: Xuhu
authors.initials: X
authors.lastname: Mao
authors.forename: Honglei
authors.initials: H
authors.lastname: Ding
authors.forename: Quanming
authors.initials: Q
authors.lastname: Zou
authors.forename: Xiao
authors.initials: X
authors.lastname: Peng
mesh_terms: D000818:Animals; D000829:Animals, Domestic / Q000382:microbiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion / Q000235:genetics; D002681:China / Q000453:epidemiology; D024901:Drug Resistance, Multiple, Bacterial; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D006041:Goats; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D013552:Swine; D014774:Virulence / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins