title: Shiga toxin-producing Escherichia coli in Central Greece: prevalence and virulence genes of O157:H7 and non-O157 in animal feces, vegetables, and humans.
abstract: In Greece, Shiga toxin-producing Escherichia coli (STEC) have only been sporadically reported. The objective of this study was to estimate the prevalence of STEC and Escherichia coli O157:H7 in farm animals, vegetables, and humans in Greece. A total number of 1,010 fecal samples were collected from farm animals (sheep, goats, cattle, chickens, pigs), 667 diarrheal samples from humans, and 60 from vegetables, which were cultured in specific media for STEC isolates. Enzyme-linked immunosorbent assay (ELISA) was used to detect toxin-producing colonies, which, subsequently, were subjected to a multiplex polymerase chain reaction (PCR) for stx1, stx2, eae, rfbE O157, and fliC h7 genes. Eighty isolates (7.9 %) from animal samples were found to produce Shiga toxin by ELISA, while by PCR, O157 STEC isolates were detected from 8 (0.8 %) samples and non-O157 STEC isolates from 43 (4.2 %) samples. STEC isolates were recovered mainly from sheep and goats, rarely from cattle, and not from pigs and chickens, suggesting that small ruminants constitute a potential risk for human infections. However, only three human specimens (0.4 %) were positive for the detection of Shiga toxins and all were PCR-negative. Similarly, all 60 vegetable samples were negative for toxin production and for toxin genes, but three samples (two roman rockets and one spinach) were positive by PCR for rfbE O157 and fliC h7 genes. These findings indicate that sheep, goats, cattle, and leafy vegetables can be a reservoir of STEC and Escherichia coli O157:H7 isolates in Greece, which are still rarely detected among humans.
authors.affiliation: Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, 22 Papakiriazi Street, 41222, Larissa, Greece.
authors.forename: O
authors.initials: O
authors.lastname: Pinaka
authors.forename: S
authors.initials: S
authors.lastname: Pournaras
authors.forename: V
authors.initials: V
authors.lastname: Mouchtouri
authors.forename: E
authors.initials: E
authors.lastname: Plakokefalos
authors.forename: A
authors.initials: A
authors.lastname: Katsiaflaka
authors.forename: F
authors.initials: F
authors.lastname: Kolokythopoulou
authors.forename: E
authors.initials: E
authors.lastname: Barboutsi
authors.forename: N
authors.initials: N
authors.lastname: Bitsolas
authors.forename: C
authors.initials: C
authors.lastname: Hadjichristodoulou
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D003967:Diarrhea / Q000453:epidemiology* / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005516:Food Microbiology; D006115:Greece / Q000453:epidemiology; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D015995:Prevalence; D017422:Sequence Analysis, DNA; D022603:Shiga Toxins / Q000032:analysis; D054323:Shiga-Toxigenic Escherichia coli / Q000302:isolation & purification*; D014675:Vegetables; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D022603:Shiga Toxins; D037521:Virulence Factors