Long-term follow-up of contacts exposed to multidrug-resistant tuberculosis in Victoria, Australia, 1995-2010

SETTING: The effectiveness of public health strategies following exposure to multidrug-resistant tuberculosis (MDR-TB) is not clear. OBJECTIVE: To perform long-term follow-up of MDR-TB contacts and review individual outcomes and management approaches. DESIGN: Retrospective review of MDR-TB contacts identified by the Victorian Department of Health from 1995 to 2010. Health records, including personal medical and pharmacy records and statewide clinical and laboratory TB databases, were searched to identify management strategies and individual outcomes. RESULTS: A total of 570 contacts of 47 MDR-TB cases were identified, with a total follow-up period of 3093 person-years of observation (PYO) since exposure. Of 570 contacts, 49 (8.6%) were considered likely to have been infected with Mycobacterium tuberculosis from index cases, and 11/49 (22.5%) of these were prescribed preventive therapy tailored to isolate susceptibility. No MDR-TB cases occurred in those receiving preventive treatment, while two cases were observed in those not treated (incidence 2878/100 000 PYO during the first 2 years post exposure). CONCLUSIONS: The risk of MDR-TB transmission to close contacts in this low-prevalence setting highlights the potential for public health strategies involving preventive treatment.