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 tuberculosis, for whom respiratory isolation was not initiated promptly.


METHODS
Epidemiological investigation.


METHODS
A tertiary-care medical center in Tennessee.


METHODS
Patients and healthcare workers potentially exposed to the infectious patient in 1992.


RESULTS
Of 172 healthcare workers exposed, 35 (20%) were judged to have acquired tuberculous infection. Risk of acquisition was greatest for nurses and medical receptionists. Active tuberculosis later developed in one healthcare worker and one hospitalized patient. Nosocomial transmission was supported by epidemiological evidence and DNA fingerprinting. The outbreak strain of Mycobacterium tuberculosis differed from other isolates at this hospital, but its DNA hybridization pattern was highly similar to that of the multidrug-resistant outbreak strain W that has been prevalent 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 molecular characteristic(s) shared by these successful outbreak strains is associated with increased transmissibility or pathogenicity and emphasizes the need for continued vigilance for tuberculosis in the nosocomial setting.
Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
D W
DW
Haas
S
S
Milton
B N
BN
Kreiswirth
V L
VL
Brinsko
P J
PJ
Bifani
W
W
Schaffner
D017088:AIDS-Related Opportunistic Infections / Q000382:microbiology* / Q000635:transmission*; D000046:Academic Medical Centers; D003428:Cross Infection / Q000382:microbiology* / Q000635:transmission*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics*; D004196:Disease Outbreaks / Q000706:statistics & numerical data; D004352:Drug Resistance, Microbial; D006801:Humans; D017053:Infection Control; D017758:Infectious Disease Transmission, Patient-to-Professional / Q000706:statistics & numerical data; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics; D016273:Occupational Exposure / Q000706:statistics & numerical data; D010564:Personnel, Hospital; D012307:Risk Factors; D012703:Serotyping; D013714:Tennessee; D014397:Tuberculosis, Pulmonary / Q000382:microbiology* / Q000635:transmission*
D004269:DNA, Bacterial