Defining pathogenic verocytotoxin-producing Escherichia coli (VTEC) from cases of human infection in the European Union, 2007-2010.

During 2007-2010, 13 545 confirmed human verocytotoxin (VT)-producing Escherichia coli (VTEC) infections were reported in the European Union, including 777 haemolytic uraemic syndrome (HUS) cases. Clinical manifestations were reported for 53% of cases, 64% of which presented with diarrhoea alone and 10% with HUS. Isolates from 85% of cases were not fully serotyped and could not be classified on the basis of the Karmali seropathotype concept. There is no single or combination of phenotypic or genetic marker(s) that fully define 'pathogenic' VTEC. Isolates which contain the vtx2 (verocytotoxin 2) gene in combination with the eae (intimin-encoding) gene or aaiC (secreted protein of enteroaggregative E. coli) and aggR (plasmid-encoded regulator) genes have been associated with a higher risk of more severe illness. A molecular approach targeting genes encoding VT and other virulence determinants is thus proposed to allow an assessment of the potential severity of disease that may be associated with a given VTEC isolate.

Cattle, weather and water: mapping Escherichia coli O157:H7 infections in humans in England and Scotland.

Entero-haemorrhagic Escherichia coli O157:H7 is a zoonotic pathogen, responsible for a relatively small number of food poisoning and illness outbreaks each year, when compared with other food-borne bacteria capable of causing infections in the population. Nevertheless, E. coli O157:H7 is a bacterial pathogen associated with severe human illnesses including bloody diarrhoea and haemolytic uremic syndrome occurring in both outbreak and sporadic settings. In England and Wales approximately 1% of all laboratory-confirmed cases of food poisoning are the result of E. coli O157:H7; however, in Scotland this figure increases to 3%. When the size of the population is taken into account and the rate of E. coli O157:H7 confirmed cases per 100,000 population is examined, the rate of E. coli 0157:H7 infections in Scotland is much greater than England and Wales. The routes of transmission have changed over time, with new routes of transmission such as farm visits emerging. The prevalence of E. coli O157:H7 has a seasonal dependency, with greater faecal shedding of the organism in the warmer months; this is directly mirrored in the increased reporting of E. coli O157:H7 infection among hospitalized patients. This review attempts to suggest why this phenomenon occurs, paying particular attention to weather, animal movement and private water supplies.

Reflection paper on MRSA in food-producing and companion animals: epidemiology and control options for human and animal health.

The scope of this reflection paper was to review the latest research on the risk of MRSA infection and colonization in animals. Attention focused on occurrence, risk factors for colonization and infection, and human contact hazard for livestock, horses, and companion animals. Whereas the clonal relationship between MRSA strains of CC398 is straightforward in livestock this is less obvious in horses. Small companion animals typically share MRSA strains that seem to exchange with a human reservoir. Management and therapeutic options have been suggested for livestock, horses, companion animals, as well as instructions on safety measures for persons in contact with animals. Conclusions were drawn with emphasis on future research activities, especially to confirm the apparent evolution of the organism and to demonstrate efficiency of control strategies.

Multiresistant Salmonella enterica serovar 4,[5],12:i:- in Europe: a new pandemic strain?

A marked increase in the prevalence of S. enterica serovar 4,[5],12:i:- with resistance to ampicillin, streptomycin, sulphonamides and tetracyclines (R-type ASSuT) has been noted in food-borne infections and in pigs/pig meat in several European countries in the last ten years. One hundred and sixteen strains of S. enterica serovar 4,[5],12:i:- from humans, pigs and pig meat isolated in England and Wales, France, Germany, Italy, Poland, Spain and the Netherlands were further subtyped by phage typing, pulsed-field gel electrophoresis and multilocus variable number tandem repeat analysis to investigate the genetic relationship among strains. PCR was performed to identify the fljB flagellar gene and the genes encoding resistance to ampicillin, streptomycin, sulphonamides and tetracyclines. Class 1 and 2 integrase genes were also sought. Results indicate that genetically related serovar 4,[5],12:i:- strains of definitive phage types DT193 and DT120 with ampicillin, streptomycin, sulphonamide and tetracycline resistance encoded by blaTEM, strA-strB, sul2 and tet(B) have emerged in several European countries, with pigs the likely reservoir of infection. Control measures are urgently needed to reduce spread of infection to humans via the food chain and thereby prevent the possible pandemic spread of serovar 4,[5],12:i:- of R-type ASSuT as occurred with S. Typhimurium DT104 during the 1990s.

Detection of Salmonella enterica serovar Typhimurium with pUO-StVR2-like virulence-resistance hybrid plasmids in the United Kingdom.

The aim of this study was to investigate the presence in the United Kingdom (UK) of Salmonella enterica serovar Typhimurium isolates carrying pUO-StVR2-like virulence-resistance hybrid plasmids that originated from pSLT. One hundred and fifty ampicillin-resistant isolates of S. Typhimurium, collected in different regions of the UK during 2006, were screened for the presence of bla (OXA-1) carried by an InH-like integron (2000 bp/bla (OXA-1)-aadA1) characteristic of pUO-StVR2. Positive isolates were tested for the presence of a large plasmid that hybridised with probes specific for the bla (OXA-1) and spvC genes, used as resistance and virulence markers of the hybrid plasmid, respectively. Eleven out of the 150 isolates fulfilled both criteria and were assigned to the S. Typhimurium pUO-StVR2 group. Nine were resistant to ampicillin, chloramphenicol, streptomycin/spectinomycin, sulfonamides and tetracycline, encoded by bla (OXA-1), catA1, aadA1-like, sul1 and tet(B), respectively, and carried a pUO-StVR2-like plasmid of ca. 130 kb. Two contained hybrid plasmids of smaller size and lacked resistance(s) to chloramphenicol or chloramphenicol and tetracycline. The eleven isolates, which showed five and six closely related XbaI and BlnI profiles, respectively, were resistant to nitrofurantoin. In conclusion, multidrug-resistant S. Typhimurium isolates of the pUO-StVR2 group, which are endemic in Spain, were also detected in the UK, albeit with a low frequency (7.3%).

A re-evaluation of the impact of temperature and climate change on foodborne illness.

The effects of temperature on reported cases of a number of foodborne illnesses in England and Wales were investigated. We also explored whether the impact of temperature had changed over time. Food poisoning, campylobacteriosis, salmonellosis, Salmonella Typhimurium infections and Salmonella Enteritidis infections were positively associated (P<0.01) with temperature in the current and previous week. Only food poisoning, salmonellosis and S. Typhimurium infections were associated with temperature 2-5 weeks previously (P<0.01). There were significant reductions also in the impact of temperature on foodborne illnesses over time. This applies to temperature in the current and previous week for all illness types (P<0.01) except S. Enteritidis infection (P=0.079). Temperature 2-5 weeks previously diminished in importance for food poisoning and S. Typhimurium infection (P<0.001). The results are consistent with reduced pathogen concentrations in food and improved food hygiene over time. These adaptations to temperature imply that current estimates of how climate change may alter foodborne illness burden are overly pessimistic.

Assessment of the microbiological safety of dried spices and herbs from production and retail premises in the United Kingdom.

A study of dried spices and herbs from retail and production premises to determine the microbiological status of such products was undertaken in the UK during 2004. According to EC Recommendation 2004/24/EC and European Spice Association specifications, 96% of 2833 retail samples and 92% of 132 production batches were of satisfactory/acceptable quality. Salmonella spp. were detected in 1.5% and 1.1% of dried spices and herbs sampled at production and retail, respectively. Overall, 3.0% of herbs and spices contained high counts of Bacillus cereus (1%, > or =10(5) cfu g(-1)), Clostridium perfringens (0.4%, > or =10(3) cfu g(-1)) and/or Escherichia coli (2.1%, > or =10(2) cfu g(-1)). Ninety percent of samples examined were recorded as being 'ready-to-use', 96% of which were of satisfactory/acceptable quality. The potential public health risk of using spices and herbs as an addition to ready-to-eat foods that potentially undergo no further processing is therefore highlighted in this study. Prevention of microbial contamination in dried herbs and spices lies in the application of good hygiene practices during growing, harvesting and processing from farm to fork, and effective decontamination. In addition, the importance of correct food handling practices and usage of herbs and spices by end users cannot be overemphasised.

Antimicrobial resistance in typhoidal and nontyphoidal salmonellae.

PURPOSE OF REVIEW: Increasing occurrence of antimicrobial resistance in both typhoidal and nontyphoidal salmonellae is a major public health problem. Recent studies documenting the occurrence and types of resistance, with particular reference to quinolones and extended spectrum cephalosporins, and new approaches to treatment are reviewed. RECENT FINDINGS: Community and hospital-based studies in different Asian and African countries show widely variable rates of resistance in Salmonella enterica serovars Typhi and Paratyphi A. Occurrence of multidrug resistance has declined in some areas, but the incidence of decreased ciprofloxacin susceptibility has reached high levels, particularly in the Indian subcontinent, and isolates with full resistance to this antimicrobial are increasingly reported. Similar variability in resistance rates occurs among nontyphoidal salmonellae, with variation between serovars and by region. There are reports of plasmid-mediated qnr genes and a variety of extended spectrum cephalosporin resistance genes in nontyphoidal serovars. Two randomized controlled trials report gatifloxacin as a potential treatment option in enteric fever caused by multidrug-resistant isolates with decreased ciprofloxacin susceptibility. SUMMARY: Patterns of resistance in Salmonella are constantly changing. Continual surveillance of resistance levels is critical for clinicians to keep abreast of treatment options, but it is often lacking in resource-poor regions of the world with the highest disease burden.

Survey of Salmonella contamination of raw shell eggs used in food service premises in the United Kingdom, 2005 through 2006.

This survey was launched after an unusual number of Salmonella Enteritidis outbreaks associated with the use of eggs in food service premises in England and Wales. Between November 2005 and December 2006, 9,528 eggs (1,588 pooled samples of 6 eggs) were collected from 1,567 food service premises in the United Kingdom, most of which (89%) were produced in the United Kingdom. Salmonella was isolated from 6 (0.38%) pools of eggs. Of these, 5 (0.31%) were Salmonella Enteritidis, which were further characterized to phage types (PTs): PT 4 (0.19%), PT 8 (0.06%), and PT 12 (0.06%). Salmonella Mbandaka was also isolated (0.06%). Salmonella was detected from five and one of pooled eggs samples that were produced in the United Kingdom and Germany, respectively; these were from different producers. The study showed evidence of poor egg storage and handling practices in food service premises, in that 55% did not store eggs under refrigerated conditions; 20.7% of eggs had expired "best before" dates or were in use after 3 weeks of lay, indicating poor stock rotation; and 37.1% pooled eggs not intended for immediate service. Eggs are a commonly consumed food that may occasionally be contaminated with Salmonella at different rates, according to their country of origin. The food service sector needs to be aware of this continuing hazard, receive appropriate food safety and hygiene training on storage and usage of raw shell eggs, adopt appropriate control measures, and follow advice provided by national food agencies in order to reduce the risk of infection.

Campylobacter and Salmonella in raw red meats in the United Kingdom: prevalence, characterization and antimicrobial resistance pattern, 2003-2005.

The prevalence of Campylobacter and Salmonella was assessed in 3959 raw red meats in the UK during 2003-2005. Meats were more frequently contaminated with Campylobacter (7.2%) than with Salmonella (2.4%). Lamb and other meats (e.g. mutton, rabbit) exhibited the highest contamination from Campylobacter (12.6% and 19.8%, respectively), compared with pork (6.3%) and beef (4.9%). Pork however had the highest contamination from Salmonella (3.9%), followed by lamb (2.0%), other meats (2.0%) and beef (1.3%). Offal samples (36.6%) were more frequently contaminated with Campylobacter or Salmonella than muscle tissue (7.0%). C. jejuni predominated in all meat types. C. coli isolates were more likely to exhibit antimicrobial drug resistance, including quinolones, than C. jejuni. Salmonella typhimurium was the most frequent Salmonella serotype isolated from meats; S. typhimurium DT104/104b isolates exhibited higher rates of multiple drug resistance than other serotypes. The findings reinforce the importance of adequate cooking of meat and good hygiene to avoid cross-contamination.

Survey of Salmonella contamination of non-United Kingdom-produced raw shell eggs on retail sale in the northwest of England and London, 2005 to 2006.

This survey was prompted by a change in the epidemiology of Salmonella Enteritidis infections in England and Wales and elsewhere in Europe and, to our knowledge, is the first survey to provide information on Salmonella contamination of non-United Kingdom eggs on retail sale. Based on 10,464 non-United Kingdom eggs (1744 pooled samples of six eggs) purchased between March 2005 and July 2006, the total weighted prevalence estimate for all Salmonella detected in non-United Kingdom eggs was 3.3%. Of the eggs sampled, most were produced in Spain (66.3%), France (20.0%), or The Netherlands (7.4%). Salmonella was detected from 4.4 and 0.3% of eggs produced in Spain and France, respectively, with weighted prevalence estimates. Eight different Salmonella serotypes were recovered from non-United Kingdom eggs, of which Salmonella Enteritidis predominated, with an estimated prevalence of 2.6%. Salmonella Enteritidis was obtained only from Spanish eggs. Nine different phage types of Salmonella Enteritidis were identified, with phage type 1 found to be the predominant phage type. Most of the Salmonella Enteritidis isolates obtained from Spanish eggs in the survey were resistant to nalidixic acid with concomitant decreased susceptibility to ciprofloxacin (0.125 to 1.0 mg/liter) or ampicillin (8.0 mg/liter). Salmonella Enteritidis phage type 1 until now had not been detected in eggs examined as part of previous United Kingdom egg surveys but has been detected in eggs of Spanish origin examined during recent national outbreaks of Salmonella Enteritidis non-phage type 4 infections in England and Wales. Eggs are a commonly consumed food that may occasionally be contaminated with Salmonella. The rates of contamination may be linked to the origin of the eggs. Consumers and caterers need to be aware of this continuing hazard, adopt appropriate control measures, and follow advice provided by national food agencies in order to reduce the risk of infection.

Characterisation of CTX-M and AmpC genes in human isolates of Escherichia coli identified between 1995 and 2003 in England and Wales.

CTX-M and AmpC genes in human isolates of Escherichia coli, their genetic environment and their host plasmids were examined. Isolates (n=103) were selected based on resistance (minimum inhibitory concentration (MIC)> or =1 microg/mL) to ceftriaxone and cefotaxime. Polymerase chain reaction (PCR) and sequencing identified 29 isolates containing bla(CTX-M-15), 1 each of bla(CTX-M-2) (a strain originating from Israel) and bla(CTX-M-40), 20 isolates containing bla(CMY-7), 4 bla(CMY-2) and 1 bla(CMY-21). This is the first study of plasmid-mediated AmpC genes in E. coli in the UK. Eleven cefoxitin-resistant, AmpC PCR-negative isolates had ampC promoter region mutations. All bla(CTX-M-15) and 24 of 25 bla(CMY) genes were associated with an ISEcp1-like element. The bla(CTX-M-2) was located in an orf513-bearing class 1 integron. Plasmid restriction digests suggest transfer of genes between different plasmid backbones.

Assessment of factors contributing to changes in the incidence of antimicrobial drug resistance in Salmonella enterica serotypes Enteritidis and Typhimurium from humans in England and Wales in 2000, 2002 and 2004.

An investigation into changes in the occurrence of antimicrobial resistance in Salmonella enterica serotypes Enteritidis and Typhimurium from human infection in England and Wales in 2000, 2002 and 2004 has shown that the incidence of strains of S. Enteritidis with resistance to nalidixic acid coupled with decreased susceptibility to ciprofloxacin has more than doubled between 2000 and 2004, whereas the overall levels of resistance in S. Typhimurium have fallen by ca. 25%. In relation to published data on veterinary sales of antimicrobials in the UK, the findings demonstrate that changes in the incidence of resistance do not correlate with changes in veterinary usage. For S. Enteritidis, important factors in the increased incidence of resistance were foreign travel and the consumption of imported foods contaminated with drug-resistant strains. For S. Typhimurium, the most important factor has been an overall decline in the occurrence of multiple drug-resistant S. Typhimurium definitive phage type 104. These studies have demonstrated that changes in the incidence of resistance in predominant salmonellas in humans in England and Wales from 2000 to 2004 are multifactorial. The findings also demonstrate that, in order to combat drug resistance in zoonotic salmonellas causing infections in humans, controls on the use of antibiotics in food animals analogous to those in operation in the UK should be implemented in countries that regularly import food into the UK.

Use of veterinary antiprotozoal products in the UK, 1998-2002.

The Veterinary Medicines Directorate, an agency of the Department for Environment, Food and Rural Affairs, collates and publishes reports detailing the quantities of veterinary antimicrobial products sold in the UK by the pharmaceutical companies. For the most part, these reports have focussed on antibacterials. This paper reports, for the first time, the sales of antiprotozoal products (as base active ingredients) in the UK over a five-year period, 1998-2002, to act as a baseline. Trends and patterns in sales of different groups of the antiprotozoal products are also evaluated. It is hoped that knowledge of sales of these products will fill the knowledge gap of the potential for overall development of antimicrobial resistance in the veterinary field and also reinforce the commitment of the UK Government to promote responsible use of antimicrobial products in the veterinary field.

Multiple antimicrobial resistant Salmonella enterica serovar Paratyphi B variant Java in cattle: a case report.

An epidemiological investigation of a calf rearing premises and a closely associated dairy herd was carried out after the isolation of Salmonella enterica serovar Paratyphi B variant Java phage type 3b variant 2 from clinically diseased calves on the premises. The isolate was resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, tetracyclines, trimethoprim and cefoperazone. The organism was widespread on the calf unit and was also recovered from the dairy premises, mainly from groups of weaned calves. The investigation was extended to 10 epidemiologically linked farms but no S Java was isolated from any of the 40 to 60 samples collected from each premises. Molecular studies showed that the S Java isolates were genetically most similar to isolates from cases of human disease associated with ornamental fish tanks or feed. Long PCR and resistance gene profiling identified a resistance island which was indistinguishable from the human 'fish tank' strain of S Java and animal and human epidemic strains of S Typhimurium DT104. The isolates were clearly distinguished from multi-resistant S Java strains commonly associated with continental poultry. This is the first report of S Java with this resistance pattern in Great Britain.

Characterization of non-virulence plasmids with homology to the virulence plasmid of Salmonella dublin.

Six wild-type (wt) strains of Salmonella typhimurium, one wt strain of S. heidelberg and 12 wt strains of Escherichia coli were isolated based on both hybridization to a 6-kb HindIII fragment of the non-virulence coding part of the S. dublin serovar-specific virulence plasmid and the absence of hybridization to the virulence genes (spv genes) of the same plasmid. Such hybridization was shown to be caused by resident plasmids in all strains and to involve the same region of 30 to 37 kb of consecutive HindIII fragments on the S. dublin virulence plasmid, suggesting a common origin of this plasmid DNA. Nine of the plasmids were selected for detailed characterization and were shown not to be of the same plasmid species. They varied in size between 44 and 88 kb, they showed incompatibility with the plasmid K-MP10, or belonged to incompatibility group X, and with the exception of five plasmids from E. coli, they showed different HindIII restriction profile patterns.

Multiple drug resistance in salmonellae in England and Wales: a comparison between 1981 and 1988.

Each year from 1981 through to 1988 the most common serotypes isolated from man in England and Wales and identified at the Division of Enteric Pathogens were S typhimurium, S enteritidis, and S virchow. In 1981 these three serotypes accounted for 45%, 12%, and 7% of isolations. The remaining 35% comprised strains belonging to a further 188 different serotypes, none of which accounted for more than 1% of the total. In 1988 S typhimurium accounted for 24% of isolations, S enteritidis 57%, and S virchow 4%. The remaining 15% comprised strains of a further 184 serotypes. The resistances to the common antimicrobial drugs in non-typhoidal salmonellas isolated in England and Wales in 1981 and 1988 were reported with particular reference to resistance to four or more antimicrobial drugs (multiple resistance). For S typhimurium the overall percentage of resistant strains varied little, but multiple resistance more than doubled from 5% to 12%; in S enteritidis the incidence remained the same. In S virchow the percentages of strains resistant to all the antimicrobial drugs and in particular, to chloramphenicol, streptomycin, trimethoprim and furazolidone, rose from 0.2% to 10.4%. Salmonella enteritis in man is usually a self limiting disease and antimicrobial treatment is seldom required; but should spread beyond the intestine occur, effective antimicrobial treatment is essential. Under these circumstances a knowledge of the likelihood of resistances to commonly available drugs could be of considerable value to the clinician.

Salmonella bacteraemia in England and Wales, 1981-1990.

AIMS: To report the incidence of nontyphoidal salmonellas in England and Wales and identified in the Division of Enteric Pathogens, London between 1981 and 1990. METHODS: Strains were serotyped and phage typed for Salmonella typhimurium, S enteritidis, and S virchow, using established methods. RESULTS: Overall, less than 2% of nontyphoidal salmonellas isolated from humans were from blood culture. The highest numbers of bloodstream isolates were from infections caused by S enteritidis and S typhimurium, but the highest incidence of septicaemias was attributable to infections with S cholerae-suis, S dublin, and S virchow. 2.2% of S typhimurium isolates phage type 204C were from blood culture; likewise, 5.5% of S virchow phage type 19. This could be a cause for concern as most isolates of both these phage types are multiresistant to antimicrobial drugs. CONCLUSIONS: Salmonella septicaemia is rare in England and Wales in other than a few serotypes of limited epidemiological importance.

Resistance to ciprofloxacin in pathogenic Enterobacteriaceae in England and Wales in 1996.

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.

Molecular epidemiology of antibiotic resistance genes in multiresistant epidemic Salmonella typhimurium DT 104.

The epidemiology of antibiotic resistance genes in epidemic multiresistant S. typhimurium DT 104 of human and animal origin was investigated. DNA prepared from 45 human and 21 animal strains isolated between 1984 and 1997, including eight isolated in other European countries, the USA, Trinidad, and South Africa and resistant to ampicillin, chloramphenicol, streptomycin, sulphonamides, spectinomycin, tetracyclines (R-type ACSSuSpT) were examined for the presence of integrons by PCR. Integron hot spots were observed in all strains conferring resistance to ACSSuSpT in two copies, determined by two discrete bands of approximately 1.0 and 1.2 kb. Direct nucleotide sequencing of the individual amplicons of selected strains indicated that the 1.0 kb gene product was ant (3")-Ia, responsible for resistance to streptomycin and spectinomycin; the 1.2 kb amplicon contained the gene blaPSE-1, encoding the beta-lactamase PSE-1 (CARB-2). Both integrons were encoded on a single XbaI macrorestriction fragment of approximately 10 kb. All isolates of DT 104 of this resistance phenotype contained the same inserted gene cassettes, irrespective of source and country of origin, supporting the suggestion of the spread of an epidemic clone. Sequence analysis of the quinolone resistance determining region (QRDR) of gyrA of 15 multiresistant strains conferring additional resistance to nalidixic acid and ciprofloxacin (R-type ACSSuSpTNxCp) identified two discrete base substitutions at codon Asp-87. Conversion of Asp-87 --> Asn was most commonly observed, in 7/10 human and 4/5 animal isolates, suggesting that this codon plays a major role in the development of ciprofloxacin resistance in multiresistant S. typhimurium DT 104.