Contamination of bronchoscopes with Mycobacterium tuberculosis and successful sterilization by low-temperature hydrogen peroxide plasma sterilization

Background: The transmission of mycobacteria by bronchoscopes has been reported several times in the last years. To explore methods to prevent transmission of tuberculosis in this way, we sterilized contaminated bronchoscopes with low-temperature hydrogen peroxide gas plasma sterilization. Methods: Bronchoscopes were contaminated with Mycobacterium tuberculosis and decontaminated with a washer/disinfecter (“normal washing”). Some were additionally disinfected with glutaraldehyde (“intensive washing”). Afterward the bronchoscopes were sterilized by low-temperature hydrogen peroxide plasma sterilization. Results: After normal washing, 8/17 samples had positive results by culture, and 7/17 had positive results by nucleic acid amplification technique. After intensive washing, all samples had negative results by culture, and 10/25 had positive results by nucleic acid amplification technique; after sterilization with low-temperature hydrogen peroxide plasma sterilization, all samples had negative results by culture and nucleic acid amplification technique. Conclusion: Washing of bronchoscopes, as performed normally, is not sufficient for decontamination of bronchoscopes. Additional disinfection is recommended. If the nucleic acid amplification technique is used for diagnostic procedures, sterilization by low-temperature hydrogen peroxide plasma sterilization is recommended to avoid false-positive results.