Stenotrophomonas maltophilia Pseudooutbreak Related to Bronchoscope Reprocessing Procedures

Abstract

ISSUE: Stenotrophomonas maltophilia (formerly Xanthamonas maltophilia, formerly Pseudomonas maltophilia), a gram-negative rod-shaped bacterium found in water, soil, and plants, has rarely been implicated in outbreaks related to inadequate bronchoscope reprocessing. In August 2003, an increase in S. maltophilia isolates from bronchoscopy cultures was noted. PROJECT: A retrospective review was conducted of S. maltophilia bronchial washing (BW) isolates from January 2001 to August 2003, which revealed 306 bronchoscopies were performed, and S. maltophilia was recovered in 67 BW specimens. RESULTS: Investigation of the bronchoscope reprocessing procedure revealed: 1) Meticulous cleaning using enzymatic solution and disposable brushes was performed. 2) Scopes were disinfected using periacetic acid (chemical sterilant) processing system. 3) Scopes were hung to dry in an open, high traffic area. 4) Manufacturers' recommendations using 70% isopropanol and filtered air to effect drying was not done. It was hypothesized that residual water, trapped in the bronchoscopes between biopsy port and suction port, created an environment for bacteria to grow and contaminate BW cultures. Residual water was aspirated and cultured from the four bronchoscopes in use (two different manufacturers). Two of the samples grew S. maltophilia. LESSONS LEARNED: In response, immediate steps were implemented: 1) On completion of chemical sterilant process, scopes are flushed with 70% isopropanol followed by filtered air to facilitate drying. 2) Scopes are hung in a vented cabinet to reduce contamination and moisture accumulation. In the first 2 months following adoption of these guidelines, 47 bronchoscopy procedures have been performed, and no cultures containing S. maltophilia from BW or bronchoscopes have been reported.