ESBL-producing Enterobacteriaceae in irrigation water

We investigated the occurrence of ESBL-producing Enterobacteriaceae (E. coli, Enterobacter spp., Citrobacter spp.) in irrigation water used for watering major fresh produce cultures located in different parts of Switzerland. ESBL-producing Enterobacteriaceae were cultured first on antibiotic-free media and then selected for resistance towards third generation cephalosporins. The obtained presumptive ESBL-producing Enterobacteriaceae were identified at species level and phenotypic antibiotic resistance profiles were obtained by disk diffusion. Finally, representative and non-redundant isolates were sequenced for detection of antibiotic resistance determinants.

本研究调查了瑞士不同地区用于浇灌主要新鲜农产品种植的灌溉水中产超广谱β-内酰胺酶肠杆菌科（ESBL-producing Enterobacteriaceae，包含大肠杆菌（E. coli）、肠杆菌属、柠檬酸杆菌属）的存在情况。研究首先在无抗生素培养基上培养产ESBL肠杆菌科菌株，随后筛选对第三代头孢菌素具有耐药性的菌株；对获得的疑似产ESBL肠杆菌科菌株进行物种水平鉴定，并通过纸片扩散法获取其表型抗生素耐药谱；最终，选取具有代表性且非冗余的分离菌株进行测序，以检测其中的抗生素耐药决定簇。