Nosocomial transmission of Mycobacterium tuberculosis from an extrapulmonary site

OBJECTIVE: To assess the extent of nosocomial transmission and risk factors associated with tuberculin skin test (TST) conversions among healthcare wo rkers (HCWs) exposed to a patient with genitourinary Mycobacterium tubercul osis. 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 requir ed drainage of a prostatic abscess and bilateral orchiectomy and expired af ter a 27-day hospitalization. Disseminated tuberculosis was diagnosed at au topsy. METHODS: Contact tracing was performed on exposed HCWs, Logistic regression was used to identify independent risk factors associated with TST conversi on. RESULTS: A total of 128 HCWs were exposed to the index patient There was no evidence of active pulmonary tuberculosis throughout the patient's hospita lization; 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 2 8 nurses, 3 of 3 autopsy personnel, 2 of 17 respiratory therapists, and 1 o f 12 surgical staff. By logistic regression, irrigation or packing of the s urgical site was the only independent risk factor associated with TST conve rsion 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 (Infect Control Hosp Epi demiol 2001;22:10-12).