Nosocomial outbreak linked to a flexible gastrointestinal endoscope contaminated with an amikacin-resistant ST17 clone of Pseudomonas aeruginosa

AbstractEndoscope contamination is infrequent but can be the source of nosocomial infections and outbreaks. In August 2016, an unexpected increase in the incidence of amikacin-resistantP. 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 bySpeI-PFGE and MLST. ACaenorhabditis 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 theC. elegans killing assay, and its biofilm-forming ability, slightly superior to that of high-risk clones ofP. aeruginosa ST175 and ST235. This ou...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research