Resistance surveillance must extend to the slaughter point

A study published on 9 September places antimicrobial resistance at the slaughter point in focus beyond the usual list of classical pathogens. Researchers in Brazil examined rectal swabs from 100 pigs slaughtered in the country’s southeast. They recovered 53 Klebsiella isolates, 47 of which were Klebsiella pneumoniae. The work does not establish a specific product risk or a foodborne outbreak; it does, however, document a reservoir of bacteria and resistance determinants relevant to One Health at slaughter.

The results are striking: 64.2% of isolates were classified as multidrug resistant. The researchers found high frequencies of non-susceptibility to tetracycline, ciprofloxacin and amoxicillin-clavulanate. Three colistin-resistant isolates carried the mcr-1 gene. Whole-genome sequencing of four multidrug-resistant isolates identified two lineages, ST45 and ST1027, differing in their resistance-gene repertoire and capsular characteristics. All sequenced isolates also carried acquired loci associated with virulence.

For the meat chain, the message is not that Klebsiella should be treated as an established product hazard in every plant. Rather, the study shows that an assessment relying solely on conventional microbiological testing misses important information about the circulation of resistance genes. The investigated situation is limited to a defined region and sampling point; its percentages cannot be transferred directly to other production systems or countries.