Endoscope contamination is infrequent but can be the source of nosocomial infections and outbreaks. In August 2016, an unexpected increase in the incidence of amikacin-resistant P. aeruginosa isolates (AK-Pae) was observed at a tertiary care center in the south of Spain. An epidemiological and microbiological investigation (August-October 2016) was performed to explain this finding. Isolates from clinical and environmental samples (2 endoscopes used for retrograde cholangiopancreatography; ERCP) were identified by MALDI-TOF. Antimicrobial susceptibility testing was performed using the MicroScan system. Whole-Genome-Sequencing (Miseq, Illumina) was performed to determine the resistome and virulome. Clonal relatedness among isolates was assessed by SpeI-PFGE and MLST. A Caenorhabditis elegans killing assay was performed for virulence testing. Biofilm formation was performed using a colorimetric assay. Four of the 5 patients infected and/or colonized with AK-Pae in August 2016 had undergone ERCP ≤5 days before sample collection. Two endoscopes were contaminated with AK-Pae. Isolates from one endoscope showed an identical PFGE pattern to 9 isolates (cluster I) and differed (1–2 bands) to 5 isolates (cluster II). Isolates from these clusters belonged to the ST17 clone. This S17 clone was characterized by its low virulence in the C. elegans killing assay, and its biofilm-forming ability, slightly superior to that of high-risk clones of P. aeruginosa ST175 and ST235. This outbreak was caused by an endoscope used for ERCP contaminated with an invasive, moderately virulent, biofilm-forming AK-Pae ST17 clone, suggesting the possible emergence of a new high-risk lineage of this clone.

内窥镜污染很少见，但可能是医院感染和爆发的来源。2016年8月，在西班牙南部的一家三级医疗中心发现了抗阿米卡星铜绿假单胞菌（AK-Pae）分离株的发病率意外增加。进行了流行病学和微生物学调查（2016年8月至10月）以解释这一发现。通过MALDI-TOF鉴定了临床和环境样品的分离物（2台用于逆行胰胆管造影的内窥镜； ERCP）。使用MicroScan系统进行了抗生素敏感性测试。进行全基因组测序（Miseq，Illumina）来确定抗药性和毒力组。通过SpeI- PFGE和MLST评估分离株之间的克隆相关性。一种进行秀丽隐杆线虫的杀灭试验以进行毒力测试。使用比色测定法进行生物膜形成。2016年8月感染和/或定植AK-Pae的5例患者中有4例在样本收集前ERCP≤5天。两个内窥镜被AK-Pae污染。一台内窥镜的分离物显示出与9个分离物（I类）相同的PFGE模式，而与5个分离物（II类）不同（1-2条带）。这些簇的分离株属于ST17克隆。该S17克隆的特征在于其在秀丽隐杆线虫杀伤试验中的低毒力及其生物膜形成能力，略高于铜绿假单胞菌的高风险克隆。ST175和ST235。此次爆发是由用于内窥镜的内镜引起的，该内窥镜被侵入性的，具有中等毒性的，形成生物膜的AK-Pae ST17克隆污染，表明该克隆可能会出现新的高风险谱系。