Molecular Approach for Tracing Dissemination Routes of Shiga Toxin-ProducingEscherichia coliO157 in Bovine Offal at Slaughter

Hiroshi Asakura,Kazuya Masuda,Shizunobu Igimi,Shigeki Yamamoto

doi:10.1155/2014/739139

Hiroshi Asakura, Kazuya Masuda + Show 2 more

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https://doi.org/10.1155/2014/739139

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Abstract

Bovine offal is currently recognized as one of the sources of human Shiga toxin-producing Escherichia coli (STEC) infection in Japan. Here, the prevalence and genetic characterization of STEC O157 in bovine feces, offal, and carcasses at slaughtering were examined between July and October in 2006. STEC O157 was detected in 31 of 301 cattle feces (10.3%) delivered from 120 farms. Simultaneously, 60 bovine-originated offal (tongue, liver, and omasum) and carcasses were randomly selected and the detection of O157 STEC was examined as well. STEC O157 was isolated from 4 tongues (6.7%), 1 liver (1.7%), 3 omasa (5.0%), and 2 carcasses (3.3%), respectively. All the O157 isolates were positive for eae and hlyA genes, and 37 of 41 isolates (90.2%) exhibited stx2c genotype. PFGE analysis revealed the identical macrogenotypes of 4-tongue- and 1-liver-originated isolates and among 2 fecal isolates from animals slaughtered consecutively. Considering their continuous detection according to the slaughtering order, we concluded that these distributions of O157 in bovine offal and feces might be due to cross-contamination at (pre)slaughter. Our data thus reposes implication of better sanitary control in diapedesis from both upper and lower sites to prevent spread of this pathogen to bovine offal at slaughtering.

Highlights

Shiga toxin (Stx)-producing Escherichia coli (STEC) is one of the major foodborne pathogens that causes diarrheal illness in humans worldwide
Here we examined the prevalence and genetic characterization of Shiga toxin-producing Escherichia coli (STEC) O157 in bovine feces and offal at slaughterhouse in Japan
Throughout the screening tests STEC O157 was detected from 31 of 301 samples from bovines feces that were slaughtered between July and September in 2006 in Japan (Table 1), of which 6 isolates were originated from animal slaughtered at the same day, even though they were delivered from different farms (Table 1). 60 offal and carcass samples were simultaneously subjected to the O157 detection tests, resulting in that the STEC O157 was isolated from 4 tongues (6.7%), 1 liver (1.7%), 3 omasa (5.0%), and 2 carcasses (Table 1)

Summary

Introduction

Shiga toxin (Stx)-producing Escherichia coli (STEC) is one of the major foodborne pathogens that causes diarrheal illness in humans worldwide. Among a number of serotypes categorized in the STEC, O157 is the most major serotype associated with human infection [1]. Infection with STEC O157 can be achieved at least in part through the intake of contaminated foods, in which dairy products and meats contaminated with animal feces or intestinal contents during/after slaughtering are considered as the most common sources [2]. In Japan, bovine offal which include liver, heart, tongue and intestines are customarily eaten, a part of which are consumed raw and the contamination with pathogenic microorganisms in these meat products is considered a high risk for human health. Here we examined the prevalence and genetic characterization of STEC O157 in bovine feces and offal at slaughterhouse in Japan

Materials and Methods

Results and Discussion

Conclusion