Levels of antimicrobial resistant (AMR) E. coli in raw UK retail pork and beef remain low, according to the Food Standards Agency (FSA).

Findings come from a survey on behalf of the European Commission to assess the frequency of certain types of AMR E. coli in raw UK meat.

One beef sample was contaminated with an E. coli containing the mcr-1 gene which can make bacteria resistant to colistin, which remains one of the antibiotics of last resort for people with multi-resistant infections caused by certain species of bacteria.

Paul Cook, FSA’s head of microbiological risk assessment, said it was thought to be the first discovery of a mcr-1 positive E. coli from retail beef in the UK.

“Although the meat came from outside the UK, further testing indicated no contamination with this E. coli on other samples and at this stage we have not been able to pinpoint the source of the contamination. However, a risk assessment has been carried out and we want to make it clear that the risk to public health is very low,” he said.

The survey between January and December 2017 saw 314 beef and 310 pork samples purchased from retail in England, Scotland, Wales and Northern Ireland.

Analysis requires initial isolation and enrichment of E. coli from all meat samples, prior to testing for AMR E. coli such as Extended Spectrum Beta Lactamases (ESBLs), AmpC and Carbapenemase-producing.

Results showed less than 1 percent of retail beef and pork samples were positive for AmpC or ESBL-producing E. coli. Only three of the 624 samples tested yielded E. coli colonies on MacConkey agar + 1mg/L cefotaxime (MCA-CTX) – two beef and one pork. None of them were positive on carbapenem agar.

Two of the isolates from MCA-CTX, one beef and one pork, had an AmpC phenotype, whilst another beef isolate had an ESBL phenotype.

No samples gave rise to viable counts of E. coli above the detection limit of 40 bacteria per gram of meat on the two selective agars used indicating numbers of resistant bacteria in the samples were low.

Data is submitted annually to the European Commission and reported in the EU Summary Report on Antimicrobial Resistance but the retailers and product brands are not identified. The findings have been collected as part of an EU-wide seven-year surveillance study. Pork and beef were last tested in 2015 while poultry was examined in 2016.

None of the isolates were resistant to the last resort carbapenem antibiotics imipenem, ertapenem and meropenem. All isolates were resistant to the beta-lactam antibiotic ampicillin and the ESBL isolate was resistant to the cephalosporin antibiotics cefotaxime and ceftazidime but sensitive to cefoxitin. However, the two AmpC isolates were resistant to cefoxitin.

Cook said tackling AMR is a priority for the FSA and UK Government.

“This survey allows us to monitor certain AMR E. coli trends over time, but also compares the UK situation with that of other EU Member States. In the recently published 2015 EU report, the UK compared favorably to results from other European countries,” he said.

Presumptive AmpC phenotype E. coli in beef in 2015 ranged from zero in Switzerland to 11.5 percent in Bulgaria (1 percent UK), whilst ESBL phenotype E. coli in beef varied from zero in Switzerland  to 17.3 percent in Bulgaria (1 percent UK).

For pork, presumptive AmpC phenotype E. coli in 2015 ranged from zero in Switzerland to 6.6 percent in Czech Republic, with the UK at 0.4; ESBL phenotype E. coli in pork varied from 0.3 percent in Sweden to 20.8 percent in Bulgaria, with the UK at 2.1 percent UK.

The FSA said the risk of acquiring AMR related infections through handling and eating contaminated meat is very low if good hygiene and cooking practices are followed. It advises cooking, chilling, cleaning and avoiding cross-contamination when handling raw meat will help minimize risk and spread.

National Pig Association (NPA) senior policy advisor, Georgina Crayford, said regular monitoring of AMR bacteria in pork products enables trends to be tracked and helps better understand the risk to consumers.

“These results highlight that the prevalence of E. coli with resistance to the highest-priority critically important antibiotics on pork remains low, which is reassuring. Antibiotic use in the pig sector reduced by more than half between 2015 and 2017, which highlights the commitment of the pork supply chain to address AMR,” she said.

NPA is the representative trade association for British commercial pig producers and is allied to the National Farmers Union.

The Responsible Use of Medicines in Agriculture Alliance (RUMA) welcomed the low level findings.

The group said UK surveillance has found the number and levels of antibiotic-resistant isolates is not increasing despite complexity in the relationship between antibiotic use and the presence of antibiotic-resistant bacteria.

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