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 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.