Escherichia coli virulence genes and clonality in strains from diarrhoea in goat kids

Abstract

Escherichia coli can cause a range of diseases either extraintestinal or intestinal, from which colibacillosis outstands among the leading causes of goat kids’ mortality. However, the related pathotypes are still unknown. The aim of this study was to determine the clonality of 41 strains of E. coli obtained from the goat kids with diarrhoea from different regions, using pulsed-field gel electrophoresis (PFGE). In addition, the presence of virulence genes of diarrhoeagenic pathotypes: EAEC, STEC/EHEC, ETEC, EPEC, and EIEC/Shigella was determined by PCR amplification. Phylogenetic grouping was determined by PCR, and serotypes were determined by conventional serology. Two clusters presented 100 % similarity, the same serotype (O25:H8), and almost the same virulence genes. The remaining were heterogeneous with a percentage of similarity from 82.8 % to 50.6 %, and one strain was non-typable by PFGE. All strains had at least one virulence gene and most of the strains showed a combination of virulence genes belonging to the STEC and ETEC pathotype. The most frequent pathotypes were those combinations of virulence genes of the STEC/ETEC with 30 strains, 7 strains with virulence genes of the STEC pathotype, and 4 strains with virulence genes of the ETEC pathotype. Regarding phylogenetic groups, a preponderance of B1 (65.85 %) and A (19.51 %) was found. The main serotypes found were O25:H8 (12.19 %), O39: H49 (4.87 %), O76: H19 (7.31 %), and OR:H? (4.87 %). In this identification, a heterogeneous E. coli population with predominant virulence genes of STEC and ETEC prevailed, and the more frequent phylogenetic groups were B1 and A.