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Hybrids of Shigatoxigenic and Enterotoxigenic Escherichia coli (STEC/ETEC) Among Human and Animal Isolates in Finland

Nyholm, O., Heinikainen, S., Pelkonen, S., Hallanvuo, S., Haukka, K., Siitonen, A.
Zoonoses and public health 2015 v.62 no.7 pp. 518-524
Alces alces, Shiga toxin-producing Escherichia coli, Shiga-like toxin 1, carrier state, cattle, diarrhea, enterotoxigenic Escherichia coli, enterotoxins, foodborne illness, genes, heat stability, human diseases, humans, hybrids, monitoring, pathogens, patients, polymerase chain reaction, serotypes, virulence, Finland
Diarrhoeagenic Escherichia coli (DEC) cause serious foodborne infections in humans. Total of 450 Shigatoxigenic E. coli (STEC) strains isolated from humans, animals and environment in Finland were examined by multiplex PCR targeting the virulence genes of various DEC pathogroups simultaneously. One per cent (3/291) of the human STEC and 14% (22/159) of the animal and environmental STEC had genes typically present in enterotoxigenic E. coli (ETEC). The strains possessed genes encoding both Shiga toxin 1 and/or 2 (stx₁ and/or stx₂) and ETEC‐specific heat‐stable (ST) enterotoxin Ia (estIa). The identified stx subtypes were stx₁ₐ, stx₁c, stx₂ₐ, stx₂d and stx₂g. The three human STEC/ETEC strains were isolated from the patients with haemolytic uraemic syndrome and diarrhoea and from an asymptomatic carrier. The animal STEC/ETEC strains were isolated from cattle and moose. The human and animal STEC/ETEC strains belonged to 11 serotypes, of which O2:H27, O15:H16, O101:H‐, O128:H8 and O141:H8 have previously been described to be associated with human disease. Identification of multiple virulence genes offers further information for assessing the virulence potential of STEC and other DEC. The emergence of novel hybrid pathogens should be taken into account in the patient care and epidemiological surveillance.