Effects of concentrate level of diet and pen configuration on prevalence of Escherichia coli O157 in finishing goats

Molecular detection of Shiga toxin-producing Escherichia coli (STEC) O157 in sheep, goats, cows and buffaloes

BACKGROUND

Shiga toxin-producing E. coli (STEC) are important foodborne pathogens that causing serious public health consequences worldwide. The present study aimed to estimate the prevalence ratio and to identify the zoonotic potential of E. coli O157 isolates in slaughtered adult sheep, goats, cows and buffaloes.

MATERIALS AND METHODS

A total of 400 Recto-anal samples were collected from two targeted sites Rawalpindi and Islamabad. Among them, 200 samples were collected from the slaughterhouse of Rawalpindi included sheep (n = 75) and goats (n = 125). While, 200 samples were collected from the slaughterhouse of Islamabad included cows (n = 120) and buffalos (n = 80). All samples were initially processed in buffered peptone water and then amplified by conventional PCR. Samples positive for E. coli O157 were then streaked onto SMAC media plates. From each positive sample, six different Sorbitol fermented pink-colored colonies were isolated and analyzed again via conventional PCR to confirm the presence of rfbE O157 gene. Isolates positive for rfbE O157 gene were then further analyzed by multiplex PCR for the presence of STEC other virulent genes (sxt1, stx2, eae and ehlyA) simultaneously.

RESULTS

Of 400 RAJ samples only 2 (0.5%) showed positive results for E. coli O157 gene, included sheep 1/75 (1.33%) and buffalo 1/80 (1.25%). However, goats (n = 125) and cows (n = 120) found negative for E. coli O157. Only 2 isolates from each positive sample of sheep (1/6) and buffalo (1/6) harbored rfbE O157 genes, while five isolates could not. The rfbE O157 isolate (01) of sheep sample did not carry any of STEC genes, while the rfbE O157 isolate (01) of buffalo sample carried sxt1, stx2, eae and ehlyA genes simultaneously.

CONCLUSION

It was concluded that healthy adult sheep and buffalo are possibly essential carriers of STEC O157. However, rfbE O157 isolate of buffalo RAJ sample carried 4 STEC virulent genes, hence considered an important source of STEC infection to humans and environment which should need to devise proper control systems.

Evidence of non-O157 Shiga toxin-producing Escherichia coli in the feces of meat goats at a U.S. slaughter plant

Shiga toxin-producing Escherichia coli (STEC) are important human pathogens, and attention to non-O157 serogroups has increased in recent years. Although cattle are normally considered the primary reservoir for STEC, recent illnesses associated with goat contact have indicated that these animals are important potential reservoirs for the organisms. The prevalence of STEC, particularly non-O157 serogroups, in U.S. goats has not been well described. Our objective was to determine the prevalence of six major non-O157 STEC serogroups in the feces of meat goats. Rectal contents from 296 goats were collected postevisceration at a slaughter plant in the southeastern United States over 9 days during a 12-week period from August through October 2012. Samples were enriched in E. coli broth, and DNA was extracted and used as template in an 11-gene multiplex PCR that detected six non-O157 serogroups (O26, O45, O103, O121, O111, and O145) and virulence genes. Samples were considered positive when at least one non-O157 STEC serotype was present with either stx₁ or stx₂. All six non-O157 serogroups were detected by PCR in our samples, and 14.5% of samples were positive for at least one serogroup. Prevalence of O26 was highest, with 6.4% of goat fecal samples positive. The prevalence of O45 was 3.4%, O103 was 4.4%, O111 was 4.1%, O121 was 1.4%, and O145 was 3.0%. Twenty-two (7.4%) of 296 fecal samples had more than one non-O157 serogroup detected in the feces. Two samples had evidence of three non-O157 STEC serogroups. Goats appear to be an important reservoir for non-O157 STEC, and further work to understand the characteristics, epidemiology, and ecology of STEC in these animals is warranted.

Prevalence and relatedness of Escherichia coli O157:H7 strains in the feces and on the hides and carcasses of U.S. meat goats at slaughter

We determined the prevalences of Escherichia coli O157:H7 in feces, hide, and carcasses of meat goats at a U.S. processing plant. Prevalences were 11.1%, 2.7%, and 2.7%, respectively. Sixteen pulsed-field gel electrophoresis (PFGE) subtypes were identified among 49 E. coli O157:H7 isolates, some of which were present on multiple sample types or collection days.

Escherichia coli O157:H7: recent advances in research on occurrence, transmission, and control in cattle and the production environment

Escherichia coli O157:H7 is a zoonotic pathogen that is an important cause of human foodborne and waterborne disease, with a spectrum of illnesses ranging from asymptomatic carriage and diarrhea to the sometimes fatal hemolytic uremic syndrome. Outbreaks of E. coli O157:H7 disease are often associated with undercooked beef, but there are other sources of transmission, including water, produce, and animal contact, which can often be linked directly or indirectly to cattle. Thus, preharvest control of this pathogen in cattle production should have a large impact on reducing the risk of human foodborne illness. In this review, we will summarize preharvest research on E. coli O157:H7 in cattle and the production environment, focusing on factors that may influence the transmission, prevalence, and levels of this pathogen, such as season, diet, high-level shedders, and animal stress. In addition, we will discuss recent research on the reduction of this pathogen in cattle production, including vaccination, probiotics, bacteriophage, and manure treatments.

Escherichia coli O157:H7 colonization in small domestic ruminants

Enterohaemorrhagic Escherichia coli O157:H7 was first implicated in human disease in the early 1980s, with ruminants cited as the primary reservoirs. Preliminary studies indicated cattle to be the sole source of E. coli O157:H7 outbreaks in humans; however, further epidemiological studies soon demonstrated that E. coli O157:H7 was widespread in other food sources and that a number of transmission routes existed. More recently, small domestic ruminants (sheep and goats) have emerged as important sources of E. coli O157:H7 human infection, particularly with the widespread popularity of petting farms and the increased use of sheep and goat food products, including unpasteurized cheeses. Although the colonization and persistence characteristics of E. coli O157:H7 in the bovine host have been studied intensively, this is not the case for small ruminants. Despite many similarities to the bovine host, the pathobiology of E. coli O157:H7 in small domestic ruminants does appear to differ significantly from that described in cattle. This review aims to critically review the current knowledge regarding colonization and persistence of E. coli O157:H7 in small domestic ruminants, including comparisons with the bovine host where appropriate.