Transmission of multi-drug resistant Pseudomonas aeruginosa between two flexible ureteroscopes and an outbreak of urinary tract infection: the fragility of endoscope decontamination

Objectives: Flexible endoscopes are difficult to decontaminate, and endoscope-associated infections are increasing. This report describes an outbreak of multi-drug resistant Pseudomonas aeruginosa identified following an increase in incidence of clinical infections associated with flexible ureteroscopy at a tertiary care centre in the UK. Methods: Clinical, laboratory and central decontamination unit (CDU) records were reviewed to determine the extent of the problem, and links to the used endoscopes. Audits of the ureteroscopy procedure, endoscopy unit and CDU were performed. Endoscopes were sampled, cultured and examined for structural integrity. All available isolates were typed. Results: Thirteen patients developed clinical infections linked to two flexible ureteroscopes. The first ureteroscope was likely colonized from a known infected patient and the second ureteroscope after use on another patient infected by the first. Risk factors identified include surface cuts, stretching and puckering of the outer cover in both ureteroscopes, absence of bedside cleaning, overnight delay between the ureteroscopy and decontamination, inadequate drying after decontamination and non-traceability of connector valves. Conclusions: The adequacy of flexible endoscope decontamination depends on numerous steps. With the increasing global incidence of multi-drug resistant organisms, stringent monitoring of the flexible endoscopy process by users and decontamination units is essential.