Cefotaxime-resistant E. coli in pigs during slaughter

This cross-sectional study investigates the abundance of cefotaxime-resistant Escherichia coli (CREC) in the faeces and tonsils of 96 pigs during slaughter. Moreover, different isolates from a selected number of pigs were tested to study the diversity of blaESBL genes within E. coli isolates from one pig.
Cefotaxime-resistant bacteria (CRB; based on enumeration results on MacConkey agar supplemented with 1 mg/L cefotaxime) were found in the faeces of 77 pigs (80%; 95% CI: 70 to 87%) and the tonsils of 91 pigs (95%; 95% CI: 88% to 98%). Cefotaxime-resistant E. coli (CREC; based on enumeration results on Tryptone Bile X-glucuronide agar supplemented with 1 mg/L cefotaxime) were detected in 72 faecal samples (75%; 95% CI: 64 to 83%) and 45 tonsil samples (47%; 95% CI: 35 to 59%), in numbers up to 5.5 and 5.6 log10 CFU/g, respectively.
Within one sample, CREC isolates with up to five different combinations of ESBL genes were observed. In three out of 16 faecal samples and six out of 14 tonsil samples, only one ESBL gene profile was found.