title: Epidemiology and characterization of Escherichia coli outbreak on a pig farm in South Africa.
abstract: An investigation of mortality of piglets through clinical signs, post-mortem, histopathology and bacteriological analyses revealed the causal organism to be Escherichia coli, mainly O149:K91:K88 which belongs to the enterotoxigenic biotypes. Molecular characterization and epidemiologic analysis elucidated it as shiga-toxin (ST) E. coli resistant to ampicillin, cefotaxime, tetracycline, trimethoprim-sulfamethoxazole, tylosin and neomycin. Conventional PCR results detected genes for ST-2, adhesin involved in diffuse adherence (AIDA-1) and F18 fimbriae virulence factors. Survival analyses and logistic regression of piglet mortality patterns showed that season of weaning, weaning weight and age of dam had significant influence on survival rate of piglets. Factors affecting pathogenicity of bowel edema and survival of affected piglets on a farm with persistent infection were reported for the first time. An association of E. coli O149:K91:K88 (F4) with clinical edema disease was made even though it has been reported in the past that this serotype does not produce ST. It was concluded that more stringent measures to mitigate the impact of the disease need to be targeted for spring and in older sows.
authors.affiliation: Johannesburg Zoo, Private Bag X13, Parkview, 2122, South Africa.|College of Agriculture and Environmental Sciences, University of South Africa, Florida Campus, Florida 1709, South Africa.
authors.forename: Arnold T
authors.initials: AT
authors.lastname: Kanengoni
authors.affiliation: Rangelands and Animal Nutrition, Agricultural Research Council-Animal Production Institute, Private Bag X02, 0062, South Africa.
authors.forename: Ronald
authors.initials: R
authors.lastname: Thomas
authors.affiliation: Bacteriology Section, Agricultural Research Council-Onderstepoort Veterinary Institute, 100 Old Soutpan Road, Onderstepoort 0110, South Africa.
authors.forename: Awoke K
authors.initials: AK
authors.lastname: Gelaw
authors.affiliation: College of Agriculture and Environmental Sciences, University of South Africa, Florida Campus, Florida 1709, South Africa.|Bacteriology Section, Agricultural Research Council-Onderstepoort Veterinary Institute, 100 Old Soutpan Road, Onderstepoort 0110, South Africa.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Madoroba
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D000818:Animals; D004196:Disease Outbreaks / Q000662:veterinary*; D024901:Drug Resistance, Multiple, Bacterial; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics* / Q000472:pathogenicity; D004768:Enterotoxins / Q000235:genetics; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000401:mortality / Q000662:veterinary*; D000072480:Farms; D036781:Fimbriae Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D022621:Shiga Toxin / Q000096:biosynthesis; D022622:Shiga Toxin 1 / Q000096:biosynthesis; D013019:South Africa / Q000453:epidemiology; D016019:Survival Analysis; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology* / Q000382:microbiology; D037521:Virulence Factors; D014886:Weaning
chemical_list: D018829:Adhesins, Bacterial; D004768:Enterotoxins; D022622:Shiga Toxin 1; D037521:Virulence Factors; D036781:Fimbriae Proteins; D022621:Shiga Toxin
keywords: F18 fimbriae; bowel edema; multidrug resistant; shiga-toxin