Prevalence and Characteristics of Intimin- and Shiga Toxin-Producing Escherichia coli from Gulls, Pigeons and Broilers in Finland.

Abstract

ABSTRACT. The role of birds as sources of Shiga toxin-and intimin-producing Escherichia coli was studied. Fecal samples from live gulls (n=86), pigeons (n=33) and broiler chickens (n=199) from 23 flocks were analyzed for stx and eae by PCR. No stx positive samples were detected. In contrast, eae E. coli were highly prevalent among gulls (40%), and was also found in pigeons (7%) and chickens (57% of the flocks contaminated). The eae positive isolates were analyzed genetically and O-serogrouped. One isolate from a pigeon was found to have stx 2f . The isolates of gulls differed from those of pigeons and chickens, and all eae E. coli isolates from birds differed from human pathogenic strains by the lack of EHEC-hlyA and bfp/EAF as well as distribution of O-serogroups. Thus, birds cannot be regarded as important carriers of zoonotic stx or eae E. coli in Finland. KEY WORDS: bird, eae, Escherichia coli. J. Vet. Med. Sci. 64(11): 1071-1073, 2002 Enterohemorrhagic Escherichia coli (EHEC), enteropathogenic E. coli (EPEC) and attaching and effacing E. coli (AEEC) are food-borne pathogens that can cause diarrhea in humans [8,10,12]. These pathogenic E. coli often possess genes for Shiga toxins (stxs) and/or for intimin outer membrane protein (eae). Escherichia coli strains with stxs are called Shiga toxin (Stx)-producing Escherichia coli (STEC). Ruminants are considered to be the main reservoir of STECs. Other domestic animals, such as goats, pigs, poultry, cats and dogs can also harbor STECs and intiminproducing E. coli [2,3]. Recently, occurrence of STECs in wild birds was investigated [14,15] and a new Stx2 variant was found in pigeons [14]. However, carriage of STEC or eae possessing E. coli in wild animals has not been thoroughly investigated.Gulls and pigeons inhabit places where human beings live and migrate between waste treatment plants, harbors, marketplaces and cattle pastures, being thus important vehicles for the spread of zoonotic infections. This study was undertaken to analyze the role of wild birds (gulls and pigeons), as well as that of broiler chickens, as reservoirs of Stx-and intimin-producing E. coli. We investigated the prevalence of these E. coli by PCR, and genetically characterized various virulence genes of the isolated strains.Escherichia coli O157:H7 strain ATCC 35150 (American Type Culture Collection, Manassas, Va) was used as a positive control for stxs, eae and intimin type γ (intimin γ). The E. coli strains 166, VR299-2 and EPEC108, used as positive control strains for intimin β, intimin ε, bundleforming pilus (bfp) and "EPEC adherence factor" (EAF) plasmid, were derived from the stock culture collection of the National Veterinary and Food Research Institute, Finland. Cloacal swabs were collected from 86 healthy gulls (Larus ridibundus n=54, and L. argentatus n=32) and 29 healthy pigeons (Culumba palumbus) between June and August 1998. A total of 115 wild birds were caught alive by net for another research purpose, and swab sampling was carried out at the same time of that investigation. ...

Antimicrobial resistance profiles and virulence factors of Escherichia coliO157 collected from a poultry processing plant*

“…According to our mPCR results, 10 (77%) of the 13 isolates had only the eaeA gene (intimin). Comparing our results on the presence of a virulence gene, similar results were found by Kobayashi et al (22) in Finland, i.e. 29 (15%) out of 199 broiler samples were positive for the eaeA gene, and also in Korea by Oh et al (23), who reported that the eaeA gene was found in 30 E. coli strains obtained from cloacal samples of 184 chicken flocks.…”

“…Intimin is required for human and animal intestinal mucosal colonization of enterohemorrhagic E. coli (7,22,23). According to our mPCR results, 10 (77%) of the 13 isolates had only the eaeA gene (intimin).…”

“…This result shows that intimin might be a significant virulence factor for E. coli O157 infections because HUS are closely related to the enterohemorrhagic E. coli-carrying eaeA gene (7,22). Therefore, E. coli O157 serotypes-carrying eaeA genes might be more pathogenic for humans.…”

“…For this reason, hygiene measures are of utmost importance. The different prevalence ratio of E. coli O157 isolation might be due to several factors including age, management practice, season, sampling method, and detection technique (4,18,21,22).…”

Bakteriyel Zoonozların Epizootiyolojisinde Potansiyel Risk: Güvercin (Columba livia domestica) Dışkısı

“…Pigeons could be able to carry many pathogenic virus, bacteria, fungus and protozoa for humans and animals without causing any diseases in themselves 1,5,7,10,16 . Domestic pigeons are one of the most important vehicle for spreading of zoonotic infections 16 .…”