Andrew Fox

Prospective use of whole genome sequencing (WGS) detected a multi-country outbreak of Salmonella Enteritidis.

Since April 2015, whole genome sequencing (WGS) has been the routine test for Salmonella identification, surveillance and outbreak investigation at the national reference laboratory in England and Wales. In May 2015, an outbreak of Salmonella Enteritidis cases was detected using WGS data and investigated. UK cases were interviewed to obtain a food history and links between suppliers were mapped to produce a food chain network for chicken eggs. The association between the food chain network and the phylogeny was explored using a network comparison approach. Food and environmental samples were taken from premises linked to cases and tested for Salmonella. Within the outbreak single nucleotide polymorphism defined cluster, 136 cases were identified in the UK and 18 in Spain. One isolate from a food containing chicken eggs was within the outbreak cluster. There was a significant association between the chicken egg food chain of UK cases and phylogeny of outbreak isolates. This is the first published Salmonella outbreak to be prospectively detected using WGS. This outbreak in the UK was linked with contemporaneous cases in Spain by WGS. We conclude that UK and Spanish cases were exposed to a common source of Salmonella-contaminated chicken eggs.

Detection and molecular characterization of Livestock-Associated MRSA in raw meat on retail sale in North West England

Limited data are available on the prevalence of livestock‐associated methicillin‐resistant Staphylococcus aureus (LA‐MRSA) in the UK. We tested 124 raw meat samples for MRSA including pork (n = 63), chicken (n = 50) and turkey (n = 11) collected from retail outlets in North West England between March and July 2015. MRSA was recovered from nine (7·3%) samples (four chicken, three pork and two turkey) from different butchers and supermarkets. Four were labelled of UK origin, three were from continental Europe; the origin was not specified for two samples. Whole‐genome sequencing (WGS), spa typing and the presence of lineage‐specific canonical single nucleotide polymorphisms confirmed that they belonged to the livestock‐associated clade of clonal complex (CC) 398. Seven (77·8%) isolates were multi‐drug resistant. Phylogenetic analyses showed the isolates were diverse, suggesting multiple silent introductions of LA‐MRSA into the UK food chain. Two chicken meat isolates belonged to a sub‐clade recently reported from human cases in Europe where poultry meat was the probable source. The low levels of MRSA identified (<20 CFU per g) and absence of enterotoxin genes suggest the risk of acquisition of, or food‐poisoning due to, LA‐MRSA is low. Nevertheless, the MRSA contamination rate is higher than previously estimated; further evaluation of the public health impacts of LA‐MRSA is warranted.

The occurrence of Salmonella in raw and ready-to-eat bean sprouts and sprouted seeds on retail sale in England and Northern Ireland.

A total of 554 samples of bean sprouts or other sprouted seeds were collected at retail sale and submitted to nine Official Control Laboratories in England and Northern Ireland during January to March 2011. Samples (100 g) were tested for the presence of Salmonella using the EN ISO 6579:2002 method. Products labelled as ready‐to‐eat comprised 23% of the samples and 61% were labelled as raw or to‐cook: the remaining 12% had no indication if the food was intended as ready‐to‐eat or ready‐to‐cook, and 4% were not recorded. Salmonella spp. were detected from four samples of mung‐bean sprouts (0·7% of all the 554 samples) and all four isolates were confirmed as Salmonella enterica serovar Abaetetuba (11 : k : 1,5). Two of the samples where Salmonella was detected were sold as ready‐to‐eat (labelled ‘rinse and serve’ only): The remaining two were from samples labelled as ready‐to‐cook.

An assessment of the microbiological safety of fresh whole‐leaf herbs from retail premises in the United Kingdom with a focus on Salmonella spp.

Fresh herbs have been associated with a number of outbreaks in recent years, in the United Kingdom and elsewhere. A study of fresh herbs was carried out to assess their microbiological safety in relation to Salmonella contamination and levels of Escherichia coli.

An assessment of the microbiological quality and safety of raw drinking milk on retail sale in England

This study aimed to review the microbiological results for raw drinking milk (RDM) samples submitted to Public Health England laboratories between 2014 and 2016 in order to produce up‐to‐date data on the microbiological safety of RDM and inform future risk assessments on its sale.

An assessment of the microbiological quality of lightly cooked food (including sous-vide) at the point of consumption in England.

This observational study aims to investigate the microbiological quality of commercially prepared lightly cooked foods with a major component of food of animal origin and collected as would be served to a consumer. A total of 356 samples were collected from catering (92%), retail (7%) or producers (1%) and all were independent of known incidents of foodborne illness. Using standard methods, all samples were tested for: the presence of Campylobacter spp. and Salmonella spp. and enumerated for levels of, Bacillus spp. including B. cereus, Clostridium perfringens, Listeria spp. including L. monocytogenes, Staphylococcus aureus, Escherichia coli, Enterobacteriacea and aerobic colony count (ACC). Results were interpreted as unsatisfactory, borderline or satisfactory according to the Health Protection Agency guidelines for assessing the microbiological safety of ready-to-eat foods placed on the market. Amongst all samples, 70% were classified as satisfactory, 18% were borderline and 12% were of unsatisfactory microbiological quality. Amongst the unsatisfactory samples, six (2%) were potentially injurious to health due to the presence of: Salmonella spp. (one duck breast); Campylobacter spp. (two duck breast and one chicken liver pâté); L. monocytogenes at 4·3 × 103 cfu (colony-forming units)/g (one duck confit with foie gras ballotin) and C. perfringens at 2·5 × 105 cfu/g (one chicken liver pâté). The remaining unsatisfactory samples were due to high levels of indicator E. coli, Enterobacteriaceae or ACC.

An assessment of the microbiological quality of liver-based pâté in England 2012-13: comparison of samples collected at retail and from catering businesses.

The purpose of this study was to investigate the microbiological quality of liver pâté. During 2012-13, a total of 870 samples, unrelated to the investigation of food-poisoning outbreaks, were collected either at retail (46%), catering (53%) or the point of manufacture (1%) and were tested using standard methods to detect Salmonella spp. or Campylobacter spp., and to enumerate for Listeria spp., including Listeria monocytogenes, Clostridium perfringens, coagulase-positive staphylococci including Staphylococcus aureus, Bacillus spp., including Bacillus cereus, Escherichia coli, Enterobacteriaceae, and aerobic colony counts (ACCs). Seventy-three percent of samples were of satisfactory microbiological quality, 18% were borderline and 9% unsatisfactory. Salmonella spp. or Campylobacter spp. was not recovered from any sample. The most common causes of unsatisfactory results were elevated ACCs (6% of the samples) and high Enterobacteriaceae counts (4% of samples). The remaining unsatisfactory results were due to elevated counts of: E. coli (three samples); B. cereus (one sample at 2·6 × 105 cfu/g); or L. monocytogenes (one sample at 2·9 × 103 cfu/g). Pâté from retail was less likely to be contaminated with L. monocytogenes than samples collected from catering and samples from supermarkets were of significantly better microbiological quality than those from catering establishments.

The occurrence of Salmonella spp. in duck eggs on sale at retail or from catering in England.

Since 2010, human salmonellosis outbreaks in the UK have been detected as associated with the consumption of duck eggs. Little data are available on the rate of occurrence of Salmonella in duck eggs. The aim of this study was to investigate the occurrence of Salmonella spp. in duck eggs on sale and from catering in England during 2011, particularly those from small‐scale production. All samples were collected independently of human salmonellosis outbreak investigations. Composite samples of 6–10 eggs (shells and contents were examined separately) were examined for the presence of Salmonella spp. using the ISO 6579:2002 method. Salmonella spp. was recovered from two of 145 samples (1·4%). In one sample, Salmonella Typhimurium DT 8 was isolated from the shells while Salm. Typhimurium DT 8 and Salm. Typhimurium DT30 were isolated from the contents. Salmonella Typhimurium DT8 was isolated from the egg shells only in the second contaminated sample. This study provides baseline data for risk assessors, regulators and the food industry and may be helpful in communicating risks associated with the consumption of this product as well as evaluating risk management options to control food safety including vaccination of ducks.

An Outbreak of Pseudomonas Aeruginosa Infection Linked to a “Black Friday” Piercing Event

Introduction Outbreaks linked to cosmetic piercing are rare, but can cause significant illness. We report the investigation and management of a point-source outbreak that occurred during a Black Friday promotional event in North West England. Methods Outbreak investigation was led by Public Health England, and included active case finding among individuals pierced at a piercing premises between 25/11/2016 (Black Friday) and 7/12/2016. Detailed epidemiological, environmental (including inspection and sampling), and microbiological investigation was undertaken. Results During the Black Friday event (25/11/2016), 45 people were pierced (13 by a newly-appointed practitioner). Eleven cases were identified (7 microbiologically-confirmed, 2 probable, and 2 possible). All cases had clinical signs of infection around piercing sites, and five required surgical intervention, with varying degrees of post-operative disfigurement. All confirmed and probable cases had a scaffold piercing placed with a guide bar by the newly-appointed practitioner. Pseudomonas aeruginosa, indistinguishable at nine-locus variable-number tandem repeat loci, was isolated from four of the confirmed cases, and from pre- and post-flush samples from five separate water taps (three sinks) in the premises. Water samples taken after remedial plumbing work confirmed elimination of Pseudomonas contamination. Discussion Although high levels of Pseudomonas water contamination and some poor infection control procedures were identified, infection appeared to require additional exposure to an inexperienced practitioner, and the more invasive scaffold piercing. A proactive collaborative approach between piercers and health and environmental officials is required to reduce outbreak risk, particularly when unusually large events are planned