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.

本横断面研究旨在探究屠宰阶段96头猪粪便与扁桃体中头孢噻肟耐药大肠埃希菌（cefotaxime-resistant Escherichia coli，CREC）的定植丰度。此外，研究选取部分猪源分离株开展检测，以分析单株大肠埃希菌分离株内ESBL编码基因（blaESBL）的多样性。
基于添加1mg/L头孢噻肟的麦康凯琼脂平板的菌落计数结果，77头猪的粪便样本（占比80%；95%置信区间（Confidence Interval, CI）：70%~87%）与91头猪的扁桃体样本（占比95%；95%置信区间：88%~98%）中均检出头孢噻肟耐药菌（cefotaxime-resistant bacteria，CRB）。基于添加1mg/L头孢噻肟的胰蛋白胨胆汁X-葡萄糖醛酸苷琼脂平板的菌落计数结果，72份粪便样本（占比75%；95%置信区间：64%~83%）与45份扁桃体样本（占比47%；95%置信区间：35%~59%）中检出头孢噻肟耐药大肠埃希菌，其菌落数最高分别可达5.5 log₁₀ CFU/g与5.6 log₁₀ CFU/g。
单一样本中可观察到携带最多5种不同ESBL基因组合的CREC分离株。16份粪便样本中有3份、14份扁桃体样本中有6份仅检出1种ESBL基因谱型。