Institute for Infectious Diseases, University of Bern, Bern, Switzerland; Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
Int J Antimicrob Agents. 2021 Sep;58(3):106382. doi: 10.1016/j.ijantimicag.2021.106382. Epub 2021 Jun 21.
Point prevalence estimates of extended-spectrum cephalosporin-resistant Escherichia coli (ESC-R-Ec) are important surveillance measures but may not uncover the ESC-R-Ec dynamics within pig farms. A longitudinal study was therefore performed by sampling individual pigs, pig farmers and the environment.
On average, 30 (range 10-46) piglets of 31 Swiss farms were sampled during the suckling, weaning and fattening stages (n= 2437 samples). In addition, stool from pig farmers and environmental samples were obtained and metadata collected by questionnaires. ESC-R-Ec was identified by routine culture, and clonal relationships and resistance genes were derived from whole genome sequencing data.
Working on pig farms was not associated with an increased prevalence of ESC-R-Ec in humans. ESC-R-Ec prevalence significantly decreased from 6.2% to 3.9% and 1.8% for the suckling, weaned and fattening pigs, respectively (P < 0.001). Within the 57 ESC-R-positive suckling piglets, persisting carriage was detected in 25 animals at two consecutive time points and one animal at three consecutive time points. Clonal spread (n=7 farms, 22.6%) and horizontal gene transfer (n=1 farm, 3%) within pigs but not between humans and animals was detected. Liquid manure (n=10 samples, 16.7%) was identified as the major environmental reservoir of ESC-R-Ec in the pig farm environment.
Pig farming practices like all-in-all-out systems, but not antimicrobial usage, were associated with reduced risk of ESC-R-Ec at the farm level. As carriage duration is normally short within the individual pigs, the risk of recolonisation and clonal spread of ESC-R-Ec might be reduced by applying appropriate decontamination strategies.
肠杆菌科细菌对扩展谱头孢菌素耐药（ESC-R-Ec）的点流行率估计是重要的监测措施，但可能无法揭示养猪场内部 ESC-R-Ec 的动态变化。因此，进行了一项纵向研究，通过对个体猪、猪农和环境进行采样。
在瑞士的 31 个养猪场中，平均对 30 头（范围 10-46 头）处于哺乳期、断奶期和育肥期的仔猪（n=2437 个样本）进行采样。此外，还采集了猪农的粪便和环境样本，并通过问卷调查收集元数据。通过常规培养鉴定 ESC-R-Ec，从全基因组测序数据中得出克隆关系和耐药基因。
在养猪场工作与人类 ESC-R-Ec 患病率增加无关。ESC-R-Ec 的流行率分别从哺乳期、断奶期和育肥期的 6.2%、3.9%和 1.8%显著下降（P<0.001）。在 57 头 ESC-R-阳性的哺乳期仔猪中，有 25 头动物在连续两个时间点和 1 头动物在连续三个时间点持续携带。在猪体内检测到克隆传播（n=7 个农场，22.6%）和水平基因转移（n=1 个农场，3%），但未在人类和动物之间检测到。在养猪场环境中，液体粪便（n=10 个样本，16.7%）被确定为 ESC-R-Ec 的主要环境储库。
全进全出等养猪场实践与农场层面 ESC-R-Ec 风险降低有关，但与抗菌药物使用无关。由于个体猪体内的携带时间通常较短，通过应用适当的去污策略，可能会降低 ESC-R-Ec 的再定植和克隆传播风险。
