Tuberculosis in Australia, 1989-1992. Bacteriologically confirmed cases and drug resistance.

OBJECTIVE

To collate statistics, including drug susceptibility, of patients with bacteriologically confirmed tuberculosis in Australia during 1989-1992.

DESIGN

Collaborative project among the five Australian mycobacterial reference laboratories.

STUDY POPULATION: 2509 Australian residents with bacteriologically confirmed tuberculosis.

OUTCOME MEASURES: Patient and specimen data, and drug susceptibility results recorded for isolates of Mycobacterium tuberculosis and Mycobacterium bovis.

RESULTS

The annual incidence during 1989-1992 was about 3.6 per 100,000. The male-to-female ratio was 1.4:1 and about half the patients were under 50. Older men had high rates of disease. Lymphatic disease was significantly more common in females; the converse was true for pulmonary and pleural disease. Resistance to at least one of the common antituberculosis drugs was detected in 14.4% of isolates, and usually involved streptomycin (7.6%) and isoniazid (8.4%). Fewer than 1% of isolates were resistant to isoniazid and rifampicin in combination.

CONCLUSIONS

By international standards, Australia remains a "low-incidence" country for tuberculosis, with a static annual incidence. Multiple drug resistance is uncommon and most patients should respond to the standard four-drug regimen. Nevertheless, because clinical data confirm that the pool of infected persons is being supplemented through immigration, and that certain population subgroups have high rates of disease, it is essential that Australia maintain effective control programs.