AN OUTBREAK OF MULTI-DRUG-RESISTANT TUBERCULOSIS IN A LONDON TEACHINGHOSPITAL

We describe the epidemiology and control of a hospital outbreak of mul ti-drug-resistant tuberculosis (MDR-TB). A human immunodeficiency viru s (HIV)-negative patient with drug-sensitive tuberculosis developed MD R-TB during a period of unsupervised therapy. She was admitted to an i solation room in a ward with HIV-positive patients, but the room, unbe known to hospital staff, was at positive-pressure relative to the main ward. Seven HIV-positive contacts developed MDR-TB. The diagnosis in the second patient was delayed, partly because acid-fast bacilli in hi s sputum were assumed to be Mycobacterium avium-intracellulare. All th e available Mycobacterium tuberculosis isolates were indistinguishable by molecular typing. Nearly 1400 staff and patient contacts were offe red screening, but the screening programme detected only one of the ca ses. Despite therapy, the index patient and two of the contacts died. HIV-positive patients are more likely than others to develop tuberculo sis after exposure, and the disease may progress more rapidly. In thes e patients the possibility that acid-fast bacilli may represent M. tub erculosis must always be considered. Patients with tuberculosis (suspe cted or proven) should not be nursed in the same wards as immunosuppre ssed patients, and should be isolated. MDR-TB cases must be isolated i n negative-pressure rooms. Hospital siderooms may be positive-pressure as a fire safety measure; infection control teams must be aware of th e airflows in all isolation rooms, and must be consulted during the de sign of hospital buildings. Good communication between infection contr ol teams and clinicians is important, and all medical and nursing staf f must be aware of the principles of management of patients with prove n or suspected tuberculosis and MDR-TB.