Shiga Toxin-Producing Escherichia coli in Faecal Samples from Wild Ruminants

SIMPLE SUMMARY: Wildlife is an important source of infectious diseases, including those caused by Shiga toxin-producing Escherichia coli (STEC). STEC are one of the most frequent bacterial agents associated with outbreaks of foodborne disease. This article analyses STEC in faecal samples from red deer and roe deer. The identified O146:H28, O146:HNM, O103:H7, O103:H21, and O45:HNM serotypes and eae/stx2b, stx1a, stx1NS/stx2b, stx2a, stx2b, and stx2g virulence profiles may be potentially pathogenic to humans. The STEC detected in faecal samples from wildlife poses risks to humans, animals, and agricultural production due to the possibility of direct contact with faeces. In conclusion, the pathogenic potential of STEC should be monitored in the context of the ‘One Health’ approach which links human health with animal and environmental health. ABSTRACT: Wildlife can harbour Shiga toxin-producing Escherichia coli (STEC). In the present study, STEC in faecal samples from red deer (n = 106) and roe deer (n = 95) were characterised. All isolates were non-O157 strains. In red deer, STEC were detected in 17.9% (n = 19) of the isolates, and the eae/stx(2b) virulence profile was detected in two isolates (10.5%). One STEC strain harboured stx(1a) (5.3%) and eighteen STEC strains harboured stx(2) (94.7%). The most prevalent stx(2) subtypes were stx(2b) (n = 12; 66.7%), stx(2a) (n = 3; 16.7%), and stx(2g) (n = 2; 11.1%). One isolate could not be subtyped (NS) with the applied primers (5.6%). The most widely identified serotypes were O146:H28 (n = 4; 21%), O146:HNM (n = 2; 10.5%), O103:H7 (n = 1; 5.3%), O103:H21 (n = 1; 5.3%), and O45:HNM (n = 1; 5.3%). In roe deer, STEC were detected in 16.8% (n = 16) of the isolates, and the eae/stx(2b) virulence profile was detected in one isolate (6.3%). Two STEC strains harboured stx(1a) (12.5%), one strain harboured stx(1NS)/stx(2b) (6.3%), and thirteen strains harboured stx(2) (81.3%). The most common subtypes were stx(2b) (n = 8; 61.5%), stx(2g) (n = 2; 15.4%), non-typeable subtypes (NS) (n = 2; 15.4%), and stx(2a) (n = 1; 7.7%). Serotype O146:H28 (n = 5; 31.3%) was identified. The study demonstrated that the zoonotic potential of STEC strains isolated from wildlife faeces should be monitored in the context of the ‘One Health’ approach which links human health with animal and environmental health.