Risk factors for TB in Australia and their association with delayed treatment completion.

BACKGROUND: Australia has a low incidence of TB and has committed to eliminating the disease. Identification of risk factors associated with TB is critical to achieving this goal.METHODS: We undertook a prospective cohort study involving persons receiving TB treatment in four Australian jurisdictions. Risk factors and their association with delayed treatment completion (treatment delayed by at least 1 month) were analysed using univariate analyses and multivariate logistic regression.RESULTS: Baseline surveys were completed for 402 persons with TB. Most (86.1%) were born overseas. Exposure to a person with TB was reported by 19.4%. Diabetes mellitus (10.2%), homelessness (9.2%), cigarette smoking (8.7%), excess alcohol consumption (6.0%) and mental illness (6.2%) were other common risk factors. At follow-up, 24.8% of patients had delayed treatment completion, which was associated with adverse events (34.1%, aOR 6.67, 95% CI 3.36-13.27), excess alcohol consumption (6.0%, aOR 21.94, 95% CI 6.03-79.85) and HIV co-infection (2.7%, aOR 8.10, 95% CI 1.16-56.60).CONCLUSIONS: We identified risk factors for TB and their association with delayed treatment completion, not all of which are routinely collected for surveillance purposes. Recognition of these risk factors should facilitate patient-centred care and assist Australia in reaching TB elimination.

Multidrug-resistant tuberculosis in Australia, 1998-2012.

OBJECTIVE: To describe the epidemiology and outcomes of multidrug-resistant tuberculosis (MDR-TB) diagnosed in Australia between 1998 and 2012. DESIGN: A retrospective review was undertaken involving all patients with laboratory-confirmed MDR-TB notified in Australia between 1998 and 2012 inclusive. Demographic, clinical and laboratory features are described. Clinical outcomes were defined according to World Health Organization definitions of treatment success (cure and treatment completion), treatment failure, death, loss to follow-up (including transfer out), or not evaluated at treatment completion. RESULTS: A total of 244 cases of MDR-TB were diagnosed in Australia during the study period, representing 1.4% of all TB cases notified. The majority were born outside Australia, including one third in Papua New Guinea. Of those with treatment outcome data available, treatment success was demonstrated in 81%. Treatment success was positively associated with use of a second-line injectable agent. Those born in Papua New Guinea were less likely to achieve treatment success. CONCLUSION: MDR-TB is uncommon in Australia. The large number of cases born in Papua New Guinea, and the poorer outcomes in this cohort, represent challenges with cross-border management of MDR-TB in the Torres Strait. Australia has an ongoing role in the prevention and management of MDR-TB locally and in the region.

Multidrug-resistant tuberculosis in New South Wales, Australia, 1999-2010: a case series report.

SETTING: The emergence of multidrug-resistant tuberculosis (MDR-TB) threatens the ongoing control of tuberculosis (TB). The Australian state of New South Wales (NSW) has low TB and MDR-TB incidence. OBJECTIVE: To examine the epidemiology and the clinical and public health management of MDR-TB in NSW. DESIGN: A retrospective case-series analysis of MDR-TB diagnosed in NSW between 1999 and 2010 was undertaken. A standardised questionnaire was used to collect information from the public health surveillance system, medical records and the State Mycobacterium Reference Laboratory about clinical features, drug susceptibility, treatment regimens, hospitalisation, risk factors for tuberculous infection, contact tracing and patient outcomes. RESULTS: Fifty-five cases of culture-confirmed MDR-TB, including two cases of extensively drug-resistant TB, were diagnosed. All cases were reviewed by an expert management panel. Fifty cases (91%) were foreign-born, and 50 cases (91%) had fully supervised treatment. Of the 55 cases, 46 (84%) successfully completed treatment, 3 (5%) died of TB and 3 (5%) required surgery. No MDR-TB cases were reported among contacts. CONCLUSION: Using a multidisciplinary, expert guided, case-management approach, the NSW TB Control Program achieved excellent MDR-TB outcomes. The impact of global increases in MDR-TB requires sustained commitment to TB in all settings.

Transmission of Mycobacterium tuberculosis from an Asian elephant (Elephas maximus) to a chimpanzee (Pan troglodytes) and humans in an Australian zoo.

Mycobacterium tuberculosis is primarily a pathogen of humans. Infections have been reported in animal species and it is emerging as a significant disease of elephants in the care of humans. With the close association between humans and animals, transmission can occur. In November 2010, a clinically healthy Asian elephant in an Australian zoo was found to be shedding M. tuberculosis; in September 2011, a sick chimpanzee at the same zoo was diagnosed with tuberculosis caused by an indistinguishable strain of M. tuberculosis. Investigations included staff and animal screening. Four staff had tuberculin skin test conversions associated with spending at least 10 hours within the elephant enclosure; none had disease. Six chimpanzees had suspected infection. A pathway of transmission between the animals could not be confirmed. Tuberculosis in an elephant can be transmissible to people in close contact and to other animals more remotely. The mechanism for transmission from elephants requires further investigation.