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Nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa following bronchoscopy associated with improper connection to the STERIS SYSTEM 1 processor.

Prakash, Udaya B. S. M.D.


Mayo Medical Center and Mayo Medical School, Rochester, Minnesota, U.S.A.

Nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa following bronchoscopy associated with improper connection to the STERIS SYSTEM 1 processor.

Infect Control Hosp Epidemiol 2001;22:409–13. Sorin M, Segal–Maurer S, Mariano N, Urban C, Combest A, Rahal JJ. Department of Medicine, New York Hospital Medical Center of Queens, Flushing, New York, U.S.A.

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This report describes the study to assess nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa (IRPA) following bronchoscopy from August through October 1998 at a university-affiliated community hospital. IRPA isolates were identified in bronchoscopic or postbronchoscopic specimens from 18 patients. Of these, 13 underwent bronchoscopy for possible malignancy or undiagnosed pulmonary infiltrates. After bronchoscopy, three patients continued to have IRPA isolated from sputum and demonstrated clinical evidence of infection requiring specific antimicrobial therapy. The remaining 15 patients had no further IRPA isolated and remained clinically well 3 months after bronchoscopy. The investigators reviewed clinical data, performed environmental cultures and molecular analysis of all IRPA isolates, and observed disinfection of bronchoscopes. Pulsed-field gel electrophoresis revealed that all strains except one were more than 95% related. STERIS SYSTEM 1 had been implemented in July 1998 as an automatic endoscope reprocessor for all endoscopes and bronchoscopes. Inspection of bronchoscope sterilization cycles revealed incorrect connectors joining the bronchoscope suction channel to the STERIS SYSTEM 1 processor, obstructing peracetic acid flow through the bronchoscope lumen. No malfunction warning was received, and spore strips remained negative. The authors conclude that the similarity of diverse connectors and limited training by the manufacturer regarding automatic endoscope reprocessors for bronchoscopes were the two factors responsible for the outbreak. Appropriate connections were implemented, and there was no further bronchoscope contamination. The authors suggest active surveillance of all bronchoscopy specimen cultures, standardization of connectors of various scopes and automated processors, and systematic education of staff by manufacturers with periodic on-site observation. The publications by Kressel et al. and Sorin et al. demonstrate the marked problem of cross-contamination of bronchoscopes, which can lead to expensive and time-consuming investigations to confirm that isolation of pathogenic organisms represents pseudo-outbreak rather than a true epidemic. Nearly 500,000 bronchoscopies and 10,000,000 gastrointestinal endoscopies are performed each year in the United States. These large numbers and the routine nature of these procedures may lead to complacency on the part of health care personnel with regard to disinfection and sterilization procedures. As discussed in these pages in the past (J Bronchol 1997;4:179–90, 1996;3:161–5, and 1994;1:77–84 ), an editorial in this journal (J Bronchol 1998;5:4–8 ), and other publications (Chest 1993;104:552–9 ), pseudoinfection caused by improper and inadequate cleaning and disinfecting of bronchoscopes is a notable problem. Calls for standardized methods to disinfect the bronchoscope have been issued because adherence to protocols for disinfection will prevent or minimize markedly the number of pseudoinfections. Such guidelines, however, will require frequent modifications because the rapid development and clinical deployment of newer equipment may be associated with newer factors for spreading infections. Constant vigilance aimed at the prevention of true infections and pseudoinfections associated with bronchoscopic procedures and the need to revise the guidelines regularly should be mandatory.

© 2002 Lippincott Williams & Wilkins, Inc.