title: Prevalence of adhesin and toxin genes in E. coli strains isolated from diarrheic and non-diarrheic pigs from smallholder herds in northern and eastern Uganda.
abstract: Enterotoxigenic E. coli (ETEC) significantly contribute to diarrhea in piglets and weaners. The smallholder pig producers in Uganda identified diarrhea as one of the major problems especially in piglets. The aim of this study was to; i) characterize the virulence factors of E. coli strains isolated from diarrheic and non-diarrheic suckling piglets and weaners from smallholder herds in northern and eastern Uganda and ii) identify and describe the post-mortem picture of ETEC infection in severely diarrheic piglets. Rectal swab samples were collected from 83 piglets and weaners in 20 herds and isolated E. coli were characterized by PCR, serotyping and hemolysis.
  
  
  
  The E. coli strains carried genes for the heat stable toxins STa, STb and EAST1 and adhesins F4 and AIDA-I. The genes for the heat labile toxin LT and adhesins F5, F6, F18 and F41 were not detected in any of the E. coli isolates. Where the serogroup could be identified, E. coli isolates from the same diarrheic pig belonged to the same serogroup. The prevalence of EAST1, STb, Stx2e, STa, AIDA-I, and F4 in the E. coli isolates from suckling piglets and weaners (diarrheic and non-diarrheic combined) was 29, 26.5, 2.4, 1.2, 16, and 8.4 %, respectively. However the prevalence of F4 and AIDA-I in E. coli from diarrheic suckling piglets alone was 22.2 and 20 %, respectively. There was no significant difference in the prevalence of the individual virulence factors in E. coli from the diarrheic and non-diarrheic pigs (p > 0.05). The main ETEC strains isolated from diarrheic and non-diarrheic pigs included F4/STb/EAST1 (7.2 %), F4/STb (1.2 %), AIDA/STb/EAST1 (8 %) and AIDA/STb (8 %). At post-mortem, two diarrheic suckling piglets carrying ETEC showed intact intestinal villi, enterocytes and brush border but with a layer of cells attached to the brush border, suggestive of ETEC infections.
  
  
  
  This study has shown that the F4 fimbriae is the most predominant in E. coli from diarrheic piglets in the study area and therefore an F4-based vaccine should be considered one of the preventive measures for controlling ETEC infections in the piglets in northern and eastern Uganda.
authors: College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda. ikwap@covab.mak.ac.ug.
authors: Kokas
authors: K
authors: Ikwap
authors: Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. Box 7070, SE-750 07, Uppsala, Sweden.
authors: Jenny
authors: J
authors: Larsson
authors: Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. Box 7070, SE-750 07, Uppsala, Sweden.
authors: Magdalena
authors: M
authors: Jacobson
authors: College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda.
authors: David Okello
authors: DO
authors: Owiny
authors: College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda.
authors: George William
authors: GW
authors: Nasinyama
authors: College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda.
authors: Immaculate
authors: I
authors: Nabukenya
authors: National Veterinary Institute, Uppsala, 751 89, Sweden.
authors: Sigbrit
authors: S
authors: Mattsson
authors: National Veterinary Institute, Uppsala, 751 89, Sweden.
authors: Anna
authors: A
authors: Aspan
authors: College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda.
authors: Joseph
authors: J
authors: Erume
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics*; D000818:Animals; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D010861:Fimbriae, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D015995:Prevalence; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000473:pathology / Q000517:prevention & control; D014454:Uganda / Q000453:epidemiology; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D004269:DNA, Bacterial; D037521:Virulence Factors
keywords: AIDA-I; Escherichia coli; F4; Hemolytic; Piglets