Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, 272 Winterthurerstrasse, 8057 Zurich, Switzerland.
J Antimicrob Chemother. 2022 Sep 30;77(10):2779-2783. doi: 10.1093/jac/dkac260.
This study aimed to investigate the faecal carriage of enterococci harbouring oxazolidinone resistance genes among healthy humans in Switzerland and to genetically characterize the isolates.
A total of 399 stool samples from healthy individuals employed in different food-processing plants were cultured on a selective medium containing 10 mg/L florfenicol. Resulting enterococci were screened by PCR for the presence of cfr, optrA and poxtA. A hybrid approach combining short-read and long-read WGS was used to analyse the genetic context of the cfr, optrA and poxtA genes.
Enterococcus faecalis (n = 6), Enterococcus faecium (n = 6), Enterococcus gallinarum (n = 1) and Enterococcus hirae (n = 2) were detected in 15/399 (3.8%) of the faecal samples. They carried cfr + poxtA, optrA, optrA + poxtA or poxtA. Four E. faecalis harbouring optrA and one E. faecium carrying poxtA were resistant to linezolid (8 mg/L). In most optrA-positive isolates, the genetic environments of optrA were highly variable, but often resembled previously described platforms. In most poxtA-positive isolates, the poxtA gene was flanked on both sides by IS1216E elements and located on medium-sized plasmids.
Faecal carriage of Enterococcus spp. harbouring cfr, optrA and poxtA in healthy humans associated with the food-production industry demonstrates the possibility of spread of oxazolidinone resistance genes into the community. Given the importance of linezolid as a last-resort antibiotic for the treatment of serious infections caused by Gram-positive pathogens, the detection of the oxazolidinone resistance determinants in enterococci from healthy humans is of concern for public health.
本研究旨在调查瑞士健康人群中产屎肠球菌携带唑烷酮类耐药基因的情况，并对分离株进行基因特征分析。
采集了 399 名在不同食品加工厂工作的健康个体的粪便样本，在含有 10mg/L 氟苯尼考的选择性培养基上进行培养。采用 PCR 方法对所得肠球菌进行 cfr、optrA 和 poxtA 检测。采用短读长和长读长 WGS 相结合的混合方法分析 cfr、optrA 和 poxtA 基因的遗传背景。
在 399 份粪便样本中的 15 份（3.8%）中检测到屎肠球菌（n=6）、粪肠球菌（n=6）、鸡肠球菌（n=1）和海氏肠球菌（n=2）。它们携带 cfr+poxtA、optrA、optrA+poxtA 或 poxtA。4 株携带 optrA 的屎肠球菌和 1 株携带 poxtA 的粪肠球菌对利奈唑胺（8mg/L）耐药。在大多数 optrA 阳性分离株中，optrA 的遗传环境高度可变，但通常类似于先前描述的平台。在大多数 poxtA 阳性分离株中，poxtA 基因两侧均被 IS1216E 元件包围，位于中等大小的质粒上。
食品生产行业健康人群中产屎肠球菌、粪肠球菌、鸡肠球菌和海氏肠球菌携带 cfr、optrA 和 poxtA，表明唑烷酮类耐药基因有可能传播到社区。鉴于利奈唑胺作为治疗革兰阳性病原体引起的严重感染的最后手段抗生素的重要性，从健康人群中分离出的肠球菌携带唑烷酮类耐药决定因素令人担忧。
