Background: Duodenoscopes are semi-critical devices used for endoscopic retrograde cholangiopancreatography (ERCP). Disinfection of these instruments is usually based on high-level disinfection procedures with a manual or automated endoscope reprocessor (AER). Duodenoscopes and AER are reported very rarely as a source of infection and outbreaks.
Aim: To investigate an outbreak caused by Pseudomonas aeruginosa in a Gastroenterology Department and ERCP unit in a university hospital and its underlying risk factors.
Method: Three patients in the gastroenterology unit were diagnosed as infected by multidrug-resistant P. aeruginosa and a case control study was conducted for detection of the risk factors. Our infection control team commenced active epidemiological surveillance to determine the cause of these infections. Clonal relationship of the strains was investigated by pulsed field gel electrophoresis (PFGE).
Results: Eight patients were affected in the gastroenterology unit during the period November 2007- February 2008. The case-control analysis confirmed that undergoing ERCP was significantly associated with isolation of P. aeruginosa (P=0.0001) in this unit. Six patients' isolates and seven environmental isolates had an indistinguishable PFGE profile, confirming cross-transmission. The healthcare worker implemented infection control measures to resolve the outbreak and no further cases occurred.
Conclusions: This outbreak resulted from failure of AER and inadequate high level disinfection procedures. AERs can cause contamination of duodenoscopes and can be related P. aeruginosa outbreaks. Reuse of ancillary materials of ERCP play a critical role in outbreak development.