An outbreak of bronchoscopy-related Mycobacterium tuberculosis infections due to lack of bronchoscope leak testing

Bronchoscopy-related transmission of Mycobacterium tuberculosis is rarely reported. In August 1999, five M tuberculosis-positive bronchial washing culture findings were noted in patients who underwent bronchoscopy in July in a hospital that reported only eight M tuberculosis-positive culture findings from 1995 to 1998, prompting further investigation.

A case was defined as a M tuberculosis-positive culture finding from specimens obtained from patients who underwent bronchoscopy during January to August of 1999. Bronchoscopy and laboratory records, procedures, and practices were reviewed. M tuberculosis isolates were compared using restriction fragment length polymorphism (RFLP) analysis.

During July 1999, 19 bronchoscopic procedures were performed in 19 patients. Bronchial washing specimens for mycobacterial culture were obtained from 18 patients. Ten cases were identified. Two case patients, including the index patient, had signs and symptoms of active tuberculosis prior to bronchoscopy. M tuberculosis infections developed in two more case patients despite starting a standard four-drug antituberculous regimen within 3 weeks after bronchoscopy. Six case patients had positive culture findings but no evidence of infection. All M tuberculosis isolates were antituberculosis-drug susceptible, and all but one were indistinguishable by RFLP analysis. Three bronchoscopes were used during the outbreak period; one bronchoscope was used in 9 of the 10 case patients (relative risk, 8.1; 95% confidence interval, 1.3 to 52). A hole was discovered in the sheath of this bronchoscope. Leak testing, a critical step in bronchoscope reprocessing, was not routinely performed at this institution.

M tuberculosis contamination of the bronchoscope occurred during the index patient's procedure. The hole in the sheath provided access to a space that was difficult to mechanically clean and chemically disinfect. The reprocessing recommendations of bronchoscope manufacturers, including leak testing after each use, should be closely followed.