A survey of 152 retail chicken and pork samples in Thailand from July to September 2023 detected mcr genes in open-market samples but none from supermarkets. All recovered mcr-positive isolates were multidrug resistant.
Key findings
- No supermarket sample was positive. Open-market positivity was 6/39 chicken samples (15.4%) and 4/30 pork samples (13.3%). Twenty-one isolates were recovered, predominantly E. coli, and all were multidrug resistant. One K. pneumoniae carried both mcr-1 and mcr-8.
Why this matters globally
The results support incorporating retail meat, particularly open markets, into One Health surveillance linking farms, food, people and the environment. The uncommon co-occurrence of resistance genes warrants genomic follow-up.
Thai researcher contribution
Srinuan Somroop of Thammasat University contributed to the international team, and sampling in Thailand provides directly relevant evidence for national AMR surveillance.
Limitations to consider
Sampling covered limited markets and months and was not nationally representative. PCR and culture positivity do not quantify consumer infection risk. Without a methodologically matched pre-ban baseline, the study cannot determine whether the colistin ban changed prevalence.