Occurrence of extended spectrum β-lactamase and AmpC genes among multidrug-resistant Escherichia coli and emergence of ST131 from poultry meat in Thailand

- High prevalence of ESBL-producing E. coli in poultry meat in Thailand was observed.
- E. coli carrying blaCTX-M and blaCMY-2 isolates were found in poultry meat samples.
- Clonal spread of blaCTX-M and blaCMY-2-positive E. coli from poultry meat was detected.
- E. coli ST131 isolates carrying blaTEM-116 or blaCMY-2 have emerged from poultry meat.

This study investigated the prevalence of antibiotic-resistant Escherichia coli using extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase as exemplars of multidrug-resistant phenotypes in poultry meat samples taken from open-air and supermarkets in Phitsanulok province, Northern Thailand. Two hundred and fifty poultry meat samples from open-air (n = 147) and supermarkets (n = 103) were analyzed. In total, 143 cefotaxime-resistant E. coli isolates comprising 78 isolates (53.1%) from open-air markets and 65 isolates (63.1%) from supermarkets were obtained. No significant difference could be observed in the prevalence of ESBL-positive E. coli between samples taken from open-air (70.5%) and supermarkets (69.2%). ESBL genotypes comprised of blaCTX-M-group 1 (69%), blaCTX-M-group 9 (13%), blaTEM-116 (1%), blaSHV-2a (1%) and blaSHV-12 (1%) were detected. 39.5% of the ESBL-negative E. coli possessed blaCMY-2. The blaCTX-M-group 1, blaCTX-M-group 9 and blaCMY-2 were successfully transferred into E. coli by conjugation at high frequencies. Repetitive palindromic-PCR of some blaCTX-M and blaCMY-2-positive E. coli isolates revealed identical DNA patterns suggesting clonal spread. Phylogenetic grouping and MLST analysis revealed that 3 isolates were E. coli ST131. Of these, 2 isolates were ESBL-negative and carried blaCMY-2. The other isolate was ESBL-positive and carried blaTEM-116. This is the first study to demonstrate ESBL and AmpC genotypes in E. coli and the first discovery of human pathogen ST131 from Thai poultry meat. Our data raises serious concerns for food safety and biosecurity in the Thai food industry.