A national survey was conducted to determine the prevalence of Escherichia coli O26, O103, O111, and O145 in feces of Scottish cattle. In total, 6,086 fecal pats from 338 farms were tested. The weighted mean percentages of farms on which shedding was detected were 23% for E. coli O26, 22% for E. coli O103, and 10% for E. coli O145. The weighted mean prevalences in fecal pats were 4.6% for E. coli O26, 2.7% for E. coli O103, and 0.7% for E. coli O145. No E. coli O111 was detected. Farms with cattle shedding E. coli serogroup O26, O103, or O145 were widely dispersed across Scotland and were identified most often in summer and autumn. However, on individual farms, fecal shedding of E. coli O26, O103, or O145 was frequently undetectable or the numbers of pats testing positive were small. For serogroup O26 or O103 there was clustering of positive pats within management groups, and the presence of an animal shedding one of these serogroups was a positive predictor for shedding by others, suggesting local transmission of infection. Carriage of vtx was rare in E. coli O103 and O145 isolates, but 49.0% of E. coli O26 isolates possessed vtx, invariably vtx 1 alone or vtx 1 and vtx 2 together. The carriage of eae and ehxA genes was highly associated in all three serogroups. Among E. coli serogroup O26 isolates, 28.9% carried vtx, eae, and ehxA-a profile consistent with E. coli O26 strains known to cause human disease.

Non-sorbitol-fermenting (NSF) Escherichia coli O157:H7 is the primary Shiga toxin-producing E. coli (STEC) serotype associated with human infection. Since 1988, sorbitol-fermenting (SF) STEC O157:NM strains have emerged and have been associated with a higher incidence of progression to hemolytic-uremic syndrome (HUS) than NSF STEC O157:H7. This study investigated bacterial factors that may account for the increased pathogenic potential of SF STEC O157:NM. While no evidence of toxin or toxin expression differences between the two O157 groups was found, the SF STEC O157:NM strains adhered at significantly higher levels to a human colonic cell line. Under the conditions tested, curli were shown to be the main factor responsible for the increased adherence to Caco-2 cells. Notably, 52 of 66 (79%) European SF STEC O157:NM strains tested bound Congo red at 37 C and this correlated with curli expression. In a subset of strains, curli expression was due to increased expression from the csgBAC promoter that was not always a consequence of increased csgD expression. The capacity of SF STEC O157:NM strains to express curli at 37 C may have relevance to the epidemiology of human infections as curliated strains could promote higher levels of colonization and inflammation in the human intestine. In turn, this could lead to increased toxin exposure and an increased likelihood of progression to HUS.

Summary Escherichia coli serogroup O26 played an important part in the early work on Verocytotoxin and is an established diarrhoeal pathogen. Recently, Verocytotoxigenic E. coli (VTEC) O26 has been increasingly associated with diarrhoeal disease and frequently linked to outbreaks and cases of haemolytic uraemic syndrome (HUS). This review investigates the pathogenicity, geographical distribution, changing epidemiology, routes of transmission and improved detection of VTEC O26. Laboratory data on VTEC O26 isolates and clinical data on HUS suggest a true difference in the incidence of VTEC O26 in different geographic locations. However, few diagnostic laboratories use molecular methods to detect VTEC and so it is difficult to assess the role of VTEC O26 in causing diarrhoeal disease. VTEC O26 is frequently found in the cattle population but rarely in food. However, the small number of outbreaks analysed to date are thought to be food‐borne rather than associated with direct or indirect contact with livestock or their faeces. The increase in awareness of VTEC O26 in the clinical and veterinary setting has coincided with the development of novel techniques that have improved our ability to detect and characterize this pathogen.

SUMMARYEscherichia coli O157 are zoonotic bacteria for which cattle are an important reservoir. Prevalence estimates for E. coli O157 in British cattle for human consumption are over 10 years old. A new baseline is needed to inform current human health risk. The British E. coli O157 in Cattle Study (BECS) ran between September 2014 and November 2015 on 270 farms across Scotland and England & Wales. This is the first study to be conducted contemporaneously across Great Britain, thus enabling comparison between Scotland and England & Wales. Herd-level prevalence estimates for E. coli O157 did not differ significantly for Scotland (0·236, 95% CI 0·166-0·325) and England & Wales (0·213, 95% CI 0·156-0·283) (P = 0·65). The majority of isolates were verocytotoxin positive. A higher proportion of samples from Scotland were in the super-shedder category, though there was no difference between the surveys in the likelihood of a positive farm having at least one super-shedder sample. E. coli O157 continues to be common in British beef cattle, reaffirming public health policy that contact with cattle and their environments is a potential infection source.

The distribution of Escherichia coli O157 in bovine feces was examined by testing multiple samples from fecal pats and determining the density of E. coli O157 in immunomagnetic separation (IMS)-positive fecal samples. The density of E. coli O157 in bovine feces was highly variable, differing by as much as 76,800 CFU g ؊1 between samples from the same fecal pat. The density in most positive samples was <100 CFU g ؊1 , the limit of reliable detection by IMS. Testing only one 1-g sample of feces per pat with IMS may result in a sensitivity of detection as low as 20 to 50%. It is therefore probable that most surveys have greatly underestimated the prevalence of E. coli O157 shedding in cattle and the proportion of farms with shedding cattle. The sensitivity of the detection of E. coli O157 in bovine feces can be as much as doubled by testing two 1-g samples per pat rather than one 1-g sample.Shiga-toxigenic Escherichia coli O157 is a major public health concern. It is associated with human illnesses ranging from uncomplicated watery diarrhea to hemorrhagic colitis and hemolytic-uremic syndrome, which may result in death (22,24,31). Cattle are an important source of E. coli O157 (15,25,39), and many surveys around the world have been conducted to estimate the prevalence of E. coli O157 shedding by cattle (20).Much research has gone into improving the sensitivity of laboratory methods for the detection of E. coli O157 and the introduction of immunomagnetic separation (IMS) and selective isolation media has greatly improved the sensitivity of E. coli O157 isolation from bovine feces (4,5,35). In contrast, the distribution of E. coli O157 in bovine feces and its impact on the accuracy of prevalence estimates reported in bovine fecal E. coli O157 shedding surveys has largely been ignored. A variety of sampling techniques have been used to collect bovine feces in surveys, including rectal swabs (11,19), rectal grab samples (15, 39), and grab or swab samples from fecal pats (10,12). In 27 surveys we reviewed, only one sample was taken from each animal or fecal pat. In 9 of these surveys, a swab from each animal or fecal pat was tested (1, 2, 10-12, 19, 29, 30, 38); in 7 surveys, 1 g of feces from each animal or pat was tested (8,16,25,26,28,32,36); in 10 surveys, Ն10 g of feces from each animal or pat was tested (3, 7, 9, 13-15, 18, 23, 34, 39). In the remaining survey, the amount of feces tested was not reported (17). The analysis of results in these 27 studies implicitly assumed homogenous distribution of E. coli in the fecal samples tested.This study investigated the distribution of E. coli O157 in bovine feces and assessed its impact on the sensitivity of shedding survey results. MATERIALS AND METHODSSampling. Fecal samples were drawn from two separate studies. In both studies, convenience samples of fecal pats were taken, with pats being sampled without replacement. In the first study, multiple 10-to 25-g samples were taken from fecal pats in three separate pens of cattle housed on straw bedding. On 23 October 2001,...

This pathogen may be the next Shiga toxin–producing E. coli of concern.

Composite wild bird feces collected at regular intervals from a garden feeding station in southwest Scotland over a 3-year period were examined for verocytotoxin-producing Escherichia coli O157. One sample was positive for Escherichia coli O157. The isolate belonged to phage type 21/28 and possessed vtx 2 , eaeA, and enterohemorrhagic E. coli hlyA genes.Verocytotoxin-producing Escherichia coli (VTEC) O157 is particularly prevalent in Scotland, where the majority of infections are sporadic (13). VTEC strains are characterized by the production of one or both of two toxins, Shiga toxin 1 or Shiga toxin 2, which are encoded by the genes vtx 1 and vtx 2 . A subset of VTEC, designated enterohemorrhagic E. coli (EHEC), carries the additional virulence genes eae, associated with attachment and effacement of enterocytes in vitro, and hly, which encodes enterohemolysin (3).Direct or indirect contact with animals and their products has been demonstrated to be important in transmission of VTEC O157 in human infections (5,7,10,14). Cattle are regarded as the main animal reservoir for VTEC O157 (9,15,24), but the organism has also been recovered from a range of other domesticated animals, including sheep, goats, pigs, horses, and dogs (23); free-ranging deer (19,20); zoo animals (4); rodents (2); and flies (2, 9). Among avian species, VTEC O157 has been reported to be present in broiler chickens (8), turkeys (11), and wild birds, including seagulls (25) and geese (22). Garden birds represent a group with which the Scottish public has increasing contact, but little is known about the potential impacts on human health that such interactions may cause. This paper is the first longitudinal study of the presence of VTEC O157 in the feces of wild birds visiting a garden feeding station in Scotland.Two hundred thirty-one composite samples of wild-bird feces were collected over a 36-month period from a garden feeding station in a rural setting in Dumfries and Galloway, Scotland, as previously described (18). Specimens were collected twice weekly and the numbers and species of birds visiting the site recorded (18). The table (60 by 40 cm and 135 cm above the ground) was scraped clean daily to remove uneaten food, husks, and feces and was disinfected only if it was heavily soiled (18). Samples were transported to the laboratory and portions removed for Salmonella and E. coli O86 testing (18). The remainder was immediately frozen at Ϫ20°C and subsequently transferred to Ϫ80°C. Samples for testing were rapidly thawed in a water bath at 50°C before being tested for E. coli O157. Previous trials using spiked feces had demonstrated that E. coli O157 numbers were maintained when subjected to this rapid thaw process following freezing at Ϫ80°C (unpublished findings).One-gram fecal samples were tested using a standard immunomagnetic separation methodology (6) followed by plating on sorbitol MacConkey agar (Oxoid, Basingstoke, United Kingdom) containing cefixime and tellurite (Mast Diagnostics, Bootle, United Kingdom) (CT-SMAC). Non-sorbitol-f...

Aims: This study investigated the occurrence and genetic diversity of Enterobacteriaceae with extended-spectrum b-lactamase (ESBL)-, AmpC-and carbapenemase-mediated resistance in British beef cattle, and related risk factors. Methods and Results: Faecal samples (n = 776) were obtained from farms in England and Wales (n = 20) and Scotland (n = 20) in 2015. Isolates from selective agars were identified by MALDI ToF mass spectrometry. Selected isolates were characterized by multiplex PCR (bla CTX-M, bla OXA, bla SHV and bla TEM genes), whole-genome sequencing (WGS), minimum inhibitory concentrations and pulsed-field gel electrophoresis. None of the faecal samples yielded carbapenem-resistant Escherichia coli. Ten (25%) of the farms tested positive for ESBL-producing CTX-M Enterobacteriaceae, 15 (37Á5%) of the farms were positive for AmpC phenotype E. coli and none were positive for carbapenem-resistant E. coli. WGS showed a total of 30 different resistance genes associated with E. coli, Citrobacter and Serratia from ESBL agars, and colocation of resistance genes with bla CTX-M1 . Buying bulls and bringing in fattening cattle from another farm were identified as significant risk factors for positive samples harbouring CTX-M Enterobacteriaceae or AmpC phenotype E. coli respectively. Conclusions: Beef cattle on a proportion of farms in GB carry ESBLproducing Enterobacteriaceae. Factors, such as operating as a closed herd, may have an important role in reducing introduction and transmission of resistant Enterobacteriaceae. The results indicate management factors may play an important role in impacting ESBL prevalence. In particular, further study would be valuable to understand the impact of maintaining a closed herd on reducing the introduction of resistant Enterobacteriaceae. Significance and Impact of the Study: This is the first study showing the presence of ESBL-producing Enterobacteriaceae in British beef cattle.