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Nosocomial transmission of Mycobacterium tuberculosis from an extrapulmonary site
E M D'Agata1, S Wise, A Stewart
1Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
Objective:
To assess the extent of nosocomial transmission and risk factors associated with tuberculin skin test (TST) conversions among healthcare workers (HCWs) exposed to a patient with genitourinary Mycobacterium tuberculosis.
Design:
Retrospective cohort study of exposed HCWs.
Setting:
A 275-bed community hospital in Middle Tennessee.
Participants:
A total of 128 exposed HCWs and the index patient, who required drainage of a prostatic abscess and bilateral orchiectomy and expired after a 27-day hospitalization. Disseminated tuberculosis was diagnosed at autopsy.
Methods:
Contact tracing was performed on exposed HCWs. Logistic regression was used to identify independent risk factors associated with TST conversion.
Results:
A total of 128 HCWs were exposed to the index patient. There was no evidence of active pulmonary tuberculosis throughout the patient's hospitalization; TST conversions occurred only among HCWs who were exposed to the patient during or after his surgical procedures. A total of 12 (13%) of 95 exposed HCWs who were previously nonreactive had newly positive TST: 6 of 28 nurses, 3 of 3 autopsy personnel, 2 of 17 respiratory therapists, and 1 of 12 surgical staff. By logistic regression, irrigation or packing of the surgical site was the only independent risk factor associated with TST conversion among nurses (odds ratio, 9; 95% confidence interval, 1.2-67; P=.03).
Conclusion:
Manipulation of infected tissues of the genitourinary tract can result in nosocomial transmission of tuberculosis.