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Aims: Evaluation of multilocus variable number tandem repeat analysis (MLVA) to subtype all isolates of Vero cytotoxin-producing Escherichia coli O157 phage type 8 in England and Wales., Methods and Results: Over a 13 month period from December 2010, 483 isolates of VTEC O157 PT8 were tested by MLVA; 39% were received in the first 4 months of 2011, when infections are generally low. One profile, or single locus variants of it, was present in 249 (52%) isolates but was not common previously. These cases represented a national increase in PT8, associated epidemiologically with soil-contaminated vegetables. Most of the 177 other MLVA profiles were unique to a single isolate. Profiles shared by >1 isolate included cases from two small community, food-borne outbreaks and 11 households. Several shared profiles were found among 23 isolates without known links. Apart from one group, isolates linked to travel abroad had very diverse profiles., Conclusions: Multilocus variable number tandem repeat analysis discriminated apparent sporadic isolates of the same PT and assisted in detection of cases in an emerging national outbreak., Significance and Impact of the Study: Multilocus variable number tandem repeat analysis is an epidemiologically valid complement to surveillance and applicable as a rapid, practical test for large numbers of isolates., (© 2013 The Society for Applied Microbiology.)

Diagnoses of Shigella flexneri in the United Kingdom (UK) are usually travel-related. However, since 2009, there has been an overall increase in UK-acquired cases. The Health Protection Agency has been investigating a national outbreak of S. flexneri detected in 2011 and which is still ongoing. Cases occurred mostly in men who have sex with men and were of serotype 3a. The investigation aimed at obtaining epidemiological data to inform targeted outbreak management and control.

At the request of the public health authorities, 31 public amenity premises in England and Wales containing animals of various species were investigated for the presence of verocytotoxigenic Escherichia coli (VTEC) O157 between 1997 and 2007, because of putative associations with human cases. VTEC O157 was confirmed in one or more species on 19 (61.3 per cent) of the premises. There were significant associations between the presence of VTEC O157 and the number of species sampled, the size of the enterprise, the presence of young cattle and the presence of adult pigs. E coli O157 was isolated from 305 (17.8 per cent) of 1715 samples taken from all the premises, and verocytotoxin genes were detected by PCR in 184 (98.4 per cent) of 187 representative isolates. On positive premises, the highest mean proportion of positive samples (29.0 per cent) was in cattle, followed by sheep (24.4 per cent), donkeys (14.6 per cent), pigs (14.3 per cent), horses (12.3 per cent) and goats (9.9 per cent). A high proportion of positive samples was obtained from camelid species sampled on three of the premises. The main phage types (PT) were 2 and 21/28, which were those most commonly isolated from human cases during the same period. A single PT was detected on 14 of the 19 positive premises, with up to six different species having the same PT.

A total of 88 uropathogenic Escherichia coli isolates, including 68 isolates from urine and 20 isolates from blood, were characterized by multilocus sequence typing (MLST). MLST has identified an important genetic lineage of E. coli, designated sequence type 131 (ST-131), represented by 52 of these isolates, 51 of which were resistant to extended-spectrum cephalosporins. ST-131 appears to be a drug-resistant uropathogenic strain of E. coli responsible for causing urinary tract infections and bacteremia and is widely disseminated among both community and hospital patients from different geographical areas in the northwest of England. Application of MLST has helped to define the population biology which may underpin the epidemiology of pathogenic E. coli strains. The portability of MLST allows the accurate monitoring of this antibiotic-resistant uropathogenic strain of E. coli and will enhance surveillance for this important group of organisms.

The aim of this study was to characterise the atypical enteropathogenic Escherichia coli (EPEC) strains isolated during a study of intestinal infectious disease in the UK by serotyping, intimin subtyping, and antimicrobial resistance typing. Serotypes, intimin subtypes, and resistance patterns of strains from cases were then compared with those from the control group. A wide range of serotypes, intimin subtypes, and antimicrobial resistance patterns was identified in isolates from both cases and controls, with O70:H11 and O111:H- being the most frequently detected serotypes. The most common intimin types were gamma and gamma(2). Thirty-six percent of the EPEC isolates were resistant to at least one antimicrobial agent. No significant differences in the characteristics of EPEC strains isolated from patients with symptoms of gastrointestinal disease versus those isolated from healthy controls were detected, although strains harbouring the beta-intimin subtype were more commonly isolated from children under 5 years of age (p=0.002). The compilation of data on atypical EPEC strains presented here indicates the need for further study of their virulence and epidemiology in order to assess their significance as human pathogens.

Between 1 January 1992 and 31 December 2002, Shiga toxin-producing Escherichia coli O157 (STEC O157) accounted for 44 of the 1645 foodborne general outbreaks of infectious intestinal disease reported to the Health Protection Agency Communicable Disease Surveillance Centre. These outbreaks, although rare, were characterized by severe infection, with 169 hospital admissions and five deaths reported. STEC O157 outbreaks were compared with other pathogens to identify factors associated with this pathogen. Single risk variable analysis and logistic regression were employed. Two distinct aetiologies were identified. Foodborne outbreaks of STEC O157 infection in England and Wales were independently associated with farms, which related to milk and milk products, and with red meats/meat products, which highlighted butchers' shops as a cause for concern. The introduction and adherence to effective control measures, based on the principles of hazard analysis, provide the best means of minimizing the risk of foodborne infection with this pathogen.

Among shigellas isolated from patients in England and Wales in 2002, 10% of subgroups A, B and C, and 13% of subgroup D (Shigella sonnei), were resistant to nalidixic acid. As a consequence, should antimicrobial therapy be indicated, the efficacy of nalidixic acid as the preferred treatment for children with bacillary dysentery has been jeopardised.

During the decade to 1999, the incidence of human infections with the zoonotic pathogen verocytotoxin-producing Escherichia coli O157 (VTEC O157) increased in England and Wales. This paper describes the results of a survey of 75 farms to determine the prevalence of faecal excretion of VTEC O157 by cattle, its primary reservoir host, in England and Wales. Faecal samples were collected from 4663 cattle between June and December 1999. The prevalence of excretion by individual cattle was 4.2 per cent (95 per cent confidence interval [CI] 2.0 to 6.4) and 10.3 per cent (95 per cent CI 5.8 to 14.8) among animals in infected herds. The within-herd prevalence on positive farms ranged from 1.1 to 51.4 per cent. At least one positive animal was identified on 29 (38.7 per cent; 95 per cent CI 28.1 to 50.4) of the farms, including dairy, suckler and fattening herds. The prevalence of excretion was least in the calves under two months of age, peaked in the calves aged between two and six months and declined thereafter. The phage types identified most widely were 4, 34 and 2, which were each found on six of the 29 positive farms.

A 12-month abattoir survey was conducted between January 1999 and January 2000, to determine the prevalence of faecal carriage of verocytotoxin-producing Escherichia coli O157 (VTEC O157) in cattle and sheep slaughtered for human consumption in Great Britain. Samples of rectum containing faeces were collected from 3939 cattle and 4171 sheep at 118 abattoirs, in numbers proportional to the throughput of the premises. The annual prevalence of faecal carriage of VTEC O157 was 4.7 per cent (95 per cent confidence interval 4.1 to 5.4) for cattle and 1.7 per cent (1.3 to 2.1) for sheep, values which were statistically significantly different from each other (P < 0.001). The organisms were recovered from both cattle and sheep slaughtered throughout the year and at abattoirs in all regions of the country, but the highest prevalence was in the summer. The most frequency recovered VTEC O157 isolates were phage types 2, 8 and 21/28 in cattle and 4 and 32 in sheep, the five most frequently isolated phage types associated with illness in people in Great Britain during the same period.

An investigation of infectious intestinal disease in England included examination of feces for Vero cytotoxin-producing Escherichia coli (VTEC). Using DNA probe hybridization 27 VTEC strains were identified, 12 were from cases, and of these three belonged to serogroup O157. The remaining 15 strains were isolated from controls. The strains were confirmed biochemically as E. coli, they were serotyped and characterized according to their toxin production, the presence of sequences encoding intimin (eae) and enterohemolysin was determined and resistance to antimicrobial agents was determined. Six of the nine cases with non-O157 VTEC were less than 16 years old, only two of the 15 controls were under 16. Infection with more than one micro-organism was also considered.

Transmission of verocytotoxin (VT)-producing Escherichia coli (VTEC) occurs by three main routes. These comprise food- or water-borne infections, acquisition of disease by direct or indirect contact with animals and person-to-person spread. Phenotypic typing of VTEC belonging to serogroup O157 is achieved by phage typing and identification of VT type. These properties quickly provide evidence for the linkage of human cases and their association to potential sources. DNA-based subtyping methods such as pulsed field gel electrophoresis (PFGE) are generally required to increase discrimination of VTEC O157 strains so that the spread of specific strains can be monitored. Phenotypic and DNA-based methods were used in the investigation of 85 general outbreaks of VTEC O157 infection between 1995 and 1999. Results were used in conjunction with epidemiological data to provide direct or indirect evidence for the likely route of transmission. Detailed strain fingerprinting identified specific food vehicles and reservoirs of infection in animals. Typing supported the implementation of measures to control the spread of infection that included pasteurisation orders, product withdrawal, temporary closure of retail premises and open farms and the introduction of HACCP-based working practices. In outbreaks involving widely distributed foods, DNA-based examination of apparently sporadic isolates with the same phage and VT type as outbreak strains was performed to identify additional potential outbreak cases and estimate the spread of infection. Strain typing was applied in outbreaks in nurseries and other institutions to monitor person-to-person spread, including careers and their families and to assess the involvement of community cases occurring at the same time. Rapid exchange of epidemiological, microbiological and typing data will be increasingly important in investigation of VTEC O157 outbreaks.

A total of 3429 isolations of verocytotoxin-producing Escherichia coli O157 (VTEC O157) was confirmed from human sources in England and Wales during the period 1995-1998. The largest annual total was 1087 in 1997. Most infections occurred in the third quarter of each year. The overall rate of infection ranged from 1.28 to 2.10/100,000 population and showed regional variation. The highest incidence was in children aged 1-4 years. Annually, between 5% and 11% of strains were from patients who had travelled abroad. There were 67 general outbreaks of infection represented by 407 (11.9%) VTEC O157 isolates. Outbreaks involved transmission by contaminated food or water, person-to-person spread and direct or indirect animal contact, and five were associated with foreign travel. The majority (76%) of strains carried verocytotoxin (VT) 2 genes and 23.3% were VT1+VT2. Most strains had the flagellar antigen H7, but c. 14% were non-motile. Approximately 20% of isolates were resistant to antimicrobial agents, predominantly streptomycin, sulphonamides and tetracycline. In addition to VTEC O157, strains of serogroup O157 that did not possess VT genes were identified. These were either derivatives of VTEC O157 that had lost VT genes or were strains with H antigens other than H7 that have never been associated with VT production. Strains of VTEC other than O157 were characterised. Most were associated with diarrhoea, bloody diarrhoea or haemolytic uraemic syndrome and had virulence markers in addition to VT.

Strains of Escherichia coli, hybridising with a DNA probe for enteroaggregative E. coli (EAggEC), were isolated from patients with infectious intestinal disease (IID) or gastro-enteritis, and healthy controls during the study of IID in England. Of 3506 cases presenting with an IID, 160 (4.6%) had faecal EAggEC as compared with 46 (1.7%) of 2772 healthy controls, 53% of EAggEC isolated from each of the 'case' and the 'control' groups adhered in a 'stacked-brick' formation. Strains from cases and controls belonged to over 39 and 14 different serogroups respectively, and approximately half of the strains isolated did not react with antisera in the current somatic antigen serotyping scheme. Forty-nine cases with EAggEC (31%) had a known history of foreign travel. Over 50% of strains isolated from cases and controls were resistant to one or more of eight antimicrobials, and antimicrobial resistance was not statistically significantly more common among cases with a known history of foreign travel (p = 0.57). These data form part of the largest investigation carried out on these organisms in the UK to date and provide the most comprehensive analysis of strains of EAggEC isolated from the general population of England.

Seven persons who attended the Glastonbury Music Festival were infected with Vero cytotoxin-producing Escherichia coli O157 and an eighth person had serological evidence of infection. Cases were reported from different parts of England. Patients were interviewed by telephone about clinical symptoms, festival attendance, camping details, food history, water exposure, and contact with mud and animals. The interviews identified no common food source, differing use of water sources and widely dispersed camping sites. Escherichia coli O157 strains from seven persons and from a cow belonging to a herd that had previously grazed the site all belonged to phage type 2 and possessed genes for Vero cytotoxin 2. Drug resistance and DNA-based tests showed that six patients were infected with strains indistinguishable from each other and from the bovine isolate. The most likely vehicle of infection was mud contaminated with Escherichia coli O157 from infected cattle.

In June 1993 an outbreak of Shigella sonnei infection at a primary school in south east England affected 42% of 327 pupils and staff. Attack rates of diarrhoea and fever were 33% for children aged 4 to 8 years, and 8% for those aged 8 to 12 years (p < 0.00001). Illness was associated with eating canteen food (relative risk 5.9; 95% confidence interval 3.4, -10.3). All strains examined were S. sonnei phage type 3, with the same antibiogram (ttSTSS), and were indistinguishable using colicin typing and biotyping (colicin type 9, E8) and pulse field gel electrophoresis. Molecular epidemiology suggested but could not confirm that the outbreak strain was introduced into the school population from the community.

Background: Recent outbreaks of vero cytotoxin (shiga toxin) producing Escherichia coli O157 (VTEC O157) infection have stimulated debate on food safety. However, 90% of cases in England and Wales are sporadic. We report a case-control study of sporadic VTEC O157 infection., Methods: We compared 85 sporadic cases of VTEC O157 infection, identified through population surveillance, with 142 controls, randomly selected from general practitioners' lists. We matched cases and controls for age, sex, and family doctor's practice. Exposures to foods, water, animals, farms, and environmental factors were recorded. We visited the premises concerned when cases had eaten beefburgers or cooked sliced meats from caterers or had had contact with a farm., Findings: Consumption of a beefburger from a catering premises other than from a fast-food chain A (a national chain) and consumption of cold cooked sliced meat (eg, in a salad or sandwich) from caterers, but not butchers, was associated with VTEC O157 infection (odds ratios 4.63 [95% CI 1.33-30.14] and 3.36 [1.04-12.74], respectively). Policies for ensuring thorough cooking of burgers by one national fast-food chain differed from the other catering premises we visited. There was evidence of person-to-person spread and transmission of VTEC O157 infection from animals., Interpretation: Local inspection of catering establishments that serve cooked meats together with public education to prevent spread on farms and in houses would reduce the burden of VTEC O157 infection by about 10% for each risk factor.

Since 1983 the incidence of resistance to ampicillin in Shigella dysenteriae, Sh. flexneri, and Sh. boydii infections in England and Wales has increased from 42% to 65% and the incidence of resistance to trimethoprim, from 6% to 64%. Furthermore, of 1524 strains received in 1995-1996, 46% were resistant to both of these antimicrobials. For Sh. sonnei almost 50% of isolates were resistant to ampicillin or trimethoprim and 15% were resistant to both of these antimicrobials. These results demonstrate that if antibiotic therapy had been indicated for infections with Sh. dysenteriae, Sh. flexneri, and Sh. boydii, then treatment with either ampicillin or trimethoprim may have been ineffective in almost 50% of cases and for Sh. sonnei, in 15% of cases. It is concluded that if it is necessary to commence treatment before the results of laboratory-based sensitivity tests are available, the best options would be to use nalidixic acid for children and a fluoroquinolone antibiotic such as ciprofloxacin or ofloxacin, for adults.

An outbreak of food poisoning due to Escherichia coli O157 phage type 2 Vero cytotoxin 2 affected 26 people in southern counties of England in May and June 1995. The organism was isolated from faecal specimens from 23 patients, 16 of whom lived in Dorset and seven in Hampshire. Isolates were indistinguishable by phage typing, Vero cytotoxin gene typing, restriction fragment length polymorphism, and pulsed field gel electrophoresis. Three associated cases, linked epidemiologically to the outbreak, were confirmed serologically by detection of antibodies to E. coli O157 lipopolysaccharide. Twenty-two of the 26 patients were adults: four were admitted to hospital with haemorrhagic colitis. Four cases were children: two were admitted to hospital with haemolytic uraemic syndrome (HUS). There were no deaths. Although E. coli O157 was not isolated from any food samples, illness was associated with having eaten cold meats in sandwiches bought from two sandwich producers, in Weymouth and in Portsmouth. Both shops were supplied by the same wholesaler, who kept no records and obtained cooked meats from several sources in packs that did not carry adequate identification marks. It was, therefore, impossible to trace back to the original producer or to investigate further to determine the origin of contamination with E. coli O157. To protect the public health it is essential that all wholesale packs of ready-to-eat food carry date codes and the producer's identification mark. Detailed record keeping should be part of hazard analysis critical control point (HACCP) systems and should be maintained throughout the chain of distribution from the producer to retail outlets.

In 1996, 6% of Escherichia coli from extraintestinal infections were resistant to ciprofloxacin with minimum inhibitory concentrations (MICs) > or = 2 mg/l (high level resistance). Low level resistance (MIC 0.125-1 mg/l) was also identified in 7% of Salmonella typhi, 4% of S paratyphi A, and 4% of non-typhoidal salmonellas. However, resistance to ciprofloxacin was rarely identified in shigellas. For E coli, physicians should be aware that treatment failures may occur when patients with invasive illness are treated with ciprofloxacin before the results of laboratory sensitivity tests are available. For salmonellas an increasing number of treatment failures have been recorded for patients infected with strains with low level resistance. Because of the increasing incidence of Enterobacteriaceae with low level resistance to ciprofloxacin, it is recommended that for this group of organisms a breakpoint of 0.125 mg/l should be included in laboratory sensitivity tests.

Vero cytotoxin-producing Escherichia coli O157 belonging to four phage types (PTs) caused 11 outbreaks of infection in England and Wales in 1995. Outbreak strains of different PTs were distinguishable by DNA-based methods. Pulsed-field gel electrophoresis best discriminated among strains belonging to the same PT, distinguishing six of the seven PT2 outbreak strains and both PT49 outbreak strains.

A study of the incidence of resistance to antimicrobial drugs in Escherichia coli from blood and CSF made in England and Wales in the 6-year period 1991 1996 has demonstrated a significant increase in the incidence of strains resistant to ampicillin and ciprofloxacin, two antibiotics used for first-line therapy of invasive disease. In particular, there has been a dramatic change in the occurrence of isolates with low level or high level resistance to ciprofloxacin; over 90% of isolates in the high level group were also resistant to at least four other antimicrobials. Physicians in England and Wales should be aware that there is now an increasing possibility of treatment failures when ciprofloxacin is used for the treatment of invasive E. coli infections.

Infection with Vero cytotoxin producing Escherichia coli O157 (VTEC O157) is a growing public health problem and the commonest cause of acute renal failure in children in the United Kingdom. Foodborne outbreaks of VTEC O157 infection have been reported in the United Kingdom, other European countries, and North America. Most cases of infection are sporadic, however, and the contribution of food vehicles, animal contact, and person to person spread in the acquisition of infection needs to be clarified. The PHLS is starting a case control study in England to identify and estimate the relative importance of risk factors for the acquisition of VTEC O157 infection. The study will run for 12 months. This article describes its objectives and asks microbiologists, public health physicians, clinicians, and others who may be asked for details about cases or to find suitable controls for their help in achieving a successful outcome.

Investigations were performed by the Laboratory of Enteric Pathogens on Vero cytotoxin-producing Escherichia coli (VTEC) in England and Wales from 1992-4. Bacterial isolates, faeces and sera obtained from patients with diarrhoea, bloody diarrhoea and haemolytic uraemic syndrome were examined. Using serotyping, Vero cytotoxin gene probing and serodiagnostic tests for E. coli O157, evidence of infection was detected in 543, 434 and 491 individuals in 1992, 1993 and 1994 respectively; VTEC of serogroup O157 were isolated from 470, 385 and 411 cases. The O157 VTEC strains belonged to at least 19 different phage types (PT) although 84% belonged to PT2, PT49, PT8, PT1 or PT4. Antibodies to E. coli O157 lipopolysaccharide were detected in 13% of the cases. The average annual rate of infection with O157 VTEC was 0.83/100000 and 12% of the 1458 individuals with evidence of infection with VTEC or E. coli O157 developed haemolytic uraemic syndrome. There were at least 18 general outbreaks and many family outbreaks.

We have reviewed all general outbreaks of infection due to Vero cytotoxin producing Escherichia coli (VTEC) O157 reported in England and Wales from 1992 to 1994. One hundred and seventy-three people were affected in 18 outbreaks, compared with 76 people in seven outbreaks in the preceding three years (1989 to 1991). Outbreaks occurred throughout England and Wales. Thirty-eight per cent of cases were admitted to hospital, 21% developed haemolytic uraemic syndrome, and 3% died. VTEC O157 infection causes particular concern because of its serious complications--haemorrhagic colitis and haemolytic uraemic syndrome, its capacity to spread from person to person as well as by food and water, and its reservoir in dairy and beef cattle.

During the summer of 1994, four cases of bloody diarrhoea and/or haemolytic uraemic syndrome were reported to the consultants in communicable disease control in Nottingham and Leicester. One case was an adult, and there were three children aged 2 to 4 years. The initial investigation failed to reveal any common foodstuff as the cause of the outbreak, but all four cases had attended a farm visitor centre in Leicestershire in the three weeks before they became ill. A further three cases were found who had visited the same farm. A joint investigation took place with environmental health officers and the local veterinary investigation centre of the Ministry of Agriculture, Fisheries and Food. A questionnaire designed to ascertain possible sources of infection was sent to all cases. Several of the animals on the farm were sampled for Escherichia coli O157 and the farm's facilities for food preparation and hygiene were assessed. The pattern of infection did not suggest a point source for the outbreak. Analysis of responses to the questionnaires failed to reveal any common factor other than the visit to the farm, and all but one case remembered stroking and feeding the animals. Food preparation in the farm restaurant appeared to be satisfactory and there was no evidence of contamination of food with pathogenic bacteria. E. coli O157: H7, PT2, VT2 was isolated from four of the seven human cases and also from four cattle and six goats. Further analysis using restriction fragment length polymorphism (RFLP) showed that the four human strains were indistinguishable from nine of the 10 animal strains. It was concluded that the most likely cause of this outbreak was direct contact with the animals. This was further supported by poor handwashing facilities and lack of information for the visitors on the importance of personal hygiene.