Prevalence and molecular characterization of sorbitol fermenting and non-fermenting Escherichia coli O157:H7(+)/H7(-) isolated from cattle at slaughterhouse and slaughterhouse wastewater.
The prevalence and seasonal distribution of E. coli O157:H7(+)/H7(-) in an array of aged cattle at slaughter and its dissemination with slaughterhouse wastewater over a two year period in Turkey were investigated. For this purpose, a total of 720 samples (240 rectoanal mucosal swap [RAMS], 240 carcass sponge and 240 bile samples) of 240 cattle categorized according to age, gender, breed and sampling site were collected along with additional 24 wastewater samples and were subjected to immunomagnetic separation based cultivation technique to efficiently isolate E. coli O157 from the background flora. Identification (rfbEO157, fliCh7), detection of major virulence factors (stx1, stx2, eaeA, hly, lpfA1-3 and espA), intimin variants (eae-α1, eae-α2, eae-β, eae-β1, eae-β2, eae-γ1 and eae-γ2/θ) and shiga toxin variants (stx1c, stx1d, stx2c, stx2d, stx2e, stx2f and stx2g) of all the isolates were assessed by PCR. From 10 (4.2%) of RAMS and 11 (4.6%) of carcass sponge samples and 5 (20.8%) of slaughterhouse wastewater samples, a total of 102 colonies (99 sorbitol negative and 3 sorbitol positive) were isolated. Overall, 17 (7.1%) and 15 (6.3%) of 240 sampled cattle were shown to harbor E. coli O157 and E. coli O157:H7, respectively either in their RAMS or carcass sponge samples analyzed. Statistically significant differences between categories; season, age, gender and breed of cattle were not observed (p>0.05). None of the isolated E. coli O157:H7(+)/H7(-) strains harbored any of the investigated intimin types other than eaeγ1 or shiga toxin variants stx1d, stx2e, stx2f or stx2g while all were lpfA1-3(+) except 5 E. coli O157:H7(-) strains. Intimin variant eaeγ1 and shiga toxin 1 variant stx1c were detected from all of the eaeA(+) (97/102, 95.1%) and stx1(+) (32/102, 31.3%) strains, respectively while from stx2(+) (80/102, 78.4%) isolates, both stx2c (68/80, 85.0%) and stx2d (12/80, 15.0%) variants were determined. In the last decade, prevalence of E. coli O157:H7 has an increasing trend in cattle. Slaughterhouses are the significant sources of environmental contamination with E. coli O157:H7. Isolation and molecular characterization of sorbitol fermenting E. coli O157:H7 are a novel finding and may lead to a revision of reference isolation procedure of E. coli O157:H7 in future.
Kirikkale University Faculty of Veterinary Medicine, Department of Food Hygiene and Technology, 71450 Yahsihan, Kirikkale, Turkey. Electronic address: naimdenizayaz@kku.edu.tr.
Naim Deniz
ND
Ayaz
Kirikkale University Faculty of Veterinary Medicine, Department of Food Hygiene and Technology, 71450 Yahsihan, Kirikkale, Turkey.
Yilmaz Emre
YE
Gencay
Republic of Turkey Ministry of Food Agriculture and Livestock, General Directorate of Food and Control, Lodumlu, Ankara, Turkey.
Irfan
I
Erol
D000003:Abattoirs; D000367:Age Factors; D000818:Animals; D001947:Breeding; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000235:genetics* / Q000302:isolation & purification; D015995:Prevalence; D012621:Seasons; D012737:Sex Factors; D014421:Turkey; D037521:Virulence Factors / Q000235:genetics; D062065:Wastewater / Q000382:microbiology*
D037521:Virulence Factors; D062065:Wastewater
Cattle; Intimin variants; Shiga toxin variants; Slaughterhouse wastewater; Sorbitol fermenting E. coli O157:H7