Fallow Deer (Dama dama) as a Reservoir of Shiga Toxin-Producing Escherichia coli (STEC)

SIMPLE SUMMARY: Infections caused by Shiga toxin-producing Escherichia (E.) coli (STEC) are the third most typically reported zoonosis within the European Union after campylobacteriosis and salmonellosis. STEC pathogens are responsible for the outbreaks of serious diseases in humans, including haemolytic uraemic syndrome (HUS), haemorrhagic colitis (HC) and diarrhoea (D). Red deer, roe deer and wild boars are important environmental reservoirs of foodborne pathogens that may cause serious diseases in humans and contaminate fresh food products. The occurrence of STEC and attaching and effacing (AE)-STEC in the Polish population of wild fallow deer was analysed in this study. The presence of potentially pathogenic STEC/AE-STEC in fallow deer poses a risk of carcass contamination, which could have serious consequences because venison can also be consumed raw as carpaccio or steak tartare. Only a few reports on wild animals as a reservoir of foodborne pathogens in European countries have been published to date, and the present study attempts to fill in this knowledge gap by assessing the possible epidemiological risk related to STEC/AE-STEC in fallow deer. Three isolates had the virulence profile that is associated with HUS/D/HC according to the FAO/WHO report. The results of this study suggest that fallow deer are carriers of STEC/AE-STEC that are potentially pathogenic to humans. ABSTRACT: Shiga toxin-producing Escherichia (E.) coli (STEC) are responsible for the outbreaks of serious diseases in humans. Only a few reports on fallow deer as a reservoir of foodborne pathogens have been published to date. The purpose of this study was to determine the occurrence of STEC strains in the fallow deer population in Poland. In all, 94 fallow deer swabs were tested. Polymerase chain reaction (PCR) was performed to detect the virulence profile of stx1, stx2 and eae or aggR genes, to identify the subtypes of stx1 and stx2 genes and to perform O and H serotyping. STEC and attaching and effacing (AE)-STEC were identified in 13 isolates (13.83%). The most hazardous virulence profile was detected in three strains, namely stx2d serotype O103:HNM, eae/stx1a serotype O26:HNM and eae/stx1a serotype O157:H7. The predominant stx gene was stx2, which was identified in 76.92% of isolates. E. coli O157 was detected in 4/94 (4.26%). Other E. coli serogroups, O26, O103, O111 and O145, were identified in 14/94 fallow deer (14.89%). The present findings suggest that fallow deer are carriers of STEC/AE-STEC that are potentially pathogenic to humans.