Duodenoscope-Related Outbreak of a Carbapenem-Resistant Klebsiella pneumoniae Identified Using Advanced Molecular Diagnostics

Background. Carbapenem-resistant Klebsiella pneumoniae infections are increasingly prevalent in North American hospitals. We describe an outbreak of carbapenem-resistant K. pneumoniae containing the bla(OXA-232) gene transmitted by contaminated duodenoscopes during endoscopic retrograde cholangiopancreatography (ERCP) procedures. Methods. An outbreak investigation was performed when 9 patients with bla(OXA-232) carbapenem-resistant K. pneumoniae infections were identified at a tertiary care hospital. The investigation included 2 case-control studies, review of duodenoscope reprocessing procedures, and culture of devices. Carbapenem-resistant Enterobacteriacieae (CRE) isolates were evaluated with polymerase chain reaction analysis for carbapenemase genes, and isolates with the bla(OXA-232) gene were subjected to whole-genome sequencing and chromosome single-nucleotide polymorphism analysis. On recognition of ERCP as a key risk factor for infection, targeted patient notification and CRE screening cultures were performed. Results. Molecular testing ultimately identified 17 patients with bla(Oxa-232) carbapenem-resistant K. pneumoniae isolates, including 9 with infections, 7 asymptomatic carriers who had undergone ERCP, and 1 additional patient who had been hospitalized in India and was probably the initial carrier. Two case-control studies established a point-source outbreak associated with 2 specific duodenoscopes. A field investigation of the use, reprocessing, and storage of deuodenoscopes did not identify deviations from US Food and Drug Administration or manufacturer recommendations for reprocessing. Conclusions. This outbreak demonstrated the previously underappreciated potential for duodenoscopes to transmit disease, even after undergoing high-level disinfection according to manufacturers' guidelines.