Nosocomial transmission of tuberculosis among mentally-handicapped patients in a long-term care facility.

Setting: A long-term care facility at Saint-Brieuc hospital, France.

Objective: To investigate a nosocomial outbreak of culture-positive pulmonary tuberculosis in 6 (40%) of 15 mentally handicapped HIV-seronegative patients.

Design: The factors contributing to the outbreak were analyzed and the restriction fragment length polymorphism (RFLP) patterns of the six Mycobacterium tuberculosis strains were compared.

Results: RFLP analysis of the six strains demonstrated an identical banding pattern, thus confirming the spread of a unique strain. A prolonged period of contagiousness due to a delay in diagnosis of the source patient, as well as crowded living conditions in the facility, probably contributed to the outbreak. Surveillance of residents and staff in contact with the source patient resulted in the detection of five secondary cases. Because effective isolation of mentally handicapped patients in the long-term care facility turned out to be difficult, the six case-patients were transferred to the pneumology department, thus limiting the spread of tuberculosis to other residents and staff.

Conclusions: The present outbreak emphasizes the difficulties of implementing control measures for preventing the nosocomial transmission of tuberculosis in long-term care facilities for mentally handicapped patients.