NOSOCOMIAL TRANSMISSION OF A DRUG-SENSITIVE W-VARIANT MYCOBACTERIUM-TUBERCULOSIS STRAIN AMONG PATIENTS WITH ACQUIRED-IMMUNODEFICIENCY-SYNDROME IN TENNESSEE

OBJECTIVE: To use DNA fingerprinting to characterize nosocomial spread of,Mycobacterium tuberculosis following hospitalization of a patient with acquired immunodeficiency syndrome and active pulmonary tuberculo sis, for whom respiratory isolation was not initiated promptly. DESIGN : Epidemiological investigation. SETTING: A tertiary-care medical cent er in Tennessee. PARTICIPANTS: Patients and healthcare workers potenti ally exposed to the infectious patient in 1992. RESULTS: Of 172 health care workers exposed, 35 (20%) were judged to have acquired tuberculou s infection. Risk of acquisition was greatest for nurses and medical r eceptionists. Active tuberculosis later developed in one healthcare wo rker and one, hospitalized patient. Nosocomial transmission was suppor ted by epidemiological evidence and DNA fingerprinting. The outbreak s train of Mycobacterium tuberculosis differed from other isolates at th is hospital, but its DNA hybridization pattern was highly similar to t hat of the multidrug-resistant outbreak strain W that has been prevale nt in New York City, suggesting a common strain ancestry. However, the Tennessee isolates were susceptible to all first-line antituberculous agents. CONCLUSIONS: This report suggests the possibility that a mole cular characteristic(s) shared by these successful outbreak strains is associated with increased transmissibility or pathogenicity and empha sizes the need for continued vigilance for tuberculosis in the nosocom ial setting (Infect Control Hosp Epidemiol 1998:19:635-639).