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Serotypes, virulence genes, intimin types and PFGE profiles of Escherichia coli isolated from piglets with diarrhoea in Slovakia

Vu-Khac, H., Holoda, E., Pilipcinec, E., Blanco, M., Blanco, J.E., Dahbi, G., Mora, A., López, C., González, E.A., Blanco, J.
Veterinary journal 2007 v.174 no.1 pp. 176-187
piglets, swine diseases, microbial genetics, diarrhea, Escherichia infections, enteropathogenic Escherichia coli, genes, disease prevalence, seroprevalence, pathogenicity, virulence, pathotypes, epidemiological studies, fimbriae, intimin, enterotoxins, Shiga-like toxins, phylogeny, polymerase chain reaction, pulsed-field gel electrophoresis, Slovakia
Two hundred and fifty Escherichia coli isolates from diarrhoeic and healthy piglets were serotyped and tested for the presence of virulence genes for fimbriae, intimin, heat-labile (LT) and heat-stable (STa and STb) enterotoxins, Stx toxins, and enteroaggregative heat-stable 1 (EAST1) enterotoxin by polymerase chain reaction (PCR). Although 220 isolates from diarrhoeic piglets belonged to 43 O serogroups and 77 O:H serotypes, 60% were of one of the 10 serogroups O2, O8, O15, O54, O84, O101, O141, O147, O149 and O157, and 60% belonged to only 10 serotypes (O8:H-, O54:H-, O84:H7, O101:H-, O141:H-, O141:H4, O147:H-, O149:H10, O163:H-, and ONT:H-). PCR showed that 79% of 220 isolates carried genes for at least one of the virulence factors tested. The gene encoding for EAST1 was the most prevalent (65%) followed by those encoding for STb (49%), LT (42%), STa (13%), and Stx2e (4%). Eighty-three (38%) of the 220 E. coli isolates carried the gene for F4 (K88), whereas genes for F18, F5 (K99), F41, F6 (P987), F17, and intimin (eae) were detected in 9%, 3%, 3%, 3%, 1%, and 3%, respectively. Seropathotype O149:H10:F4:LT/STb/EAST1 (70 isolates) was the most common, representing 32% of isolates. Pulsed-field gel electrophoresis (PFGE) analysis with XbaI of 15 O149:H10 representative isolates from diarrhoeic piglets distinguished 14 types. The 15 isolates exhibited a wide variability of distinct restriction patterns though all belonged to the same serotype (O149:H10), and all but one showed identical virulence determinants (F4, LT, STb, and EAST1). Among 30 isolates from healthy piglets only two virulence genes were detected: EAST1 (26%) and eae (17%). In total, 12 isolates were positives for the eae gene: five isolates had intimin β1, four possessed intimin θ and three showed intimin type ξB. This is believed to be the first study describing the presence of intimin type ξB in E. coli of porcine origin.