Microbial contamination of suction tubes attached to suction instruments and preventive methods.

We investigated the microbial contamination of suction tubes attached to wall-type suction instruments. Microbial contamination of suction tubes used for endoscopy or sputum suction in hospital wards was examined before and after their disinfection. In addition, disinfection and washing methods for suction tubes were evaluated. Suction tubes (n=33) before disinfection were contaminated with 10(2)-10(8) colony-forming units (cfu)/tube. The main contaminants were Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia. The suction tubes were disinfected with sodium hypochlorite (n=11) or hot water (n=11), or by an automatic tube cleaner (n=11). After 2-h immersion in 0.1% (1,000 ppm) sodium hypochlorite, 10(3)-10(7) cfu/tube of bacteria were detected in all 11 tubes examined. After washing in hot running water (65 degrees C), 10(3)-10(7) cfu/tube were detected in 3 of the 11 examined tubes. The bacteria detected in the suction tubes after disinfection with sodium hypochlorite or hot water were P. aeruginosa, A. baumannii, and S. maltophilia. On the other hand, after washing with warm water (40 degrees C) using the automatic tube cleaner, contamination was found to be <20 cfu/tube (lower detection limit, 20 cfu/tube) in all 11 tubes examined. These results suggest the usefulness of washing with automatic tube cleaners.