Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 1997: Report of the Australian Mycobacterium Reference Laboratory Network

Abstract

The Australian Mycobacterium Reference Laboratory Network collected and analysed laboratory data on new diagnoses of infection with Mycobacterium tuberculosis complex during 1997. A total of 722 cases were identified, representing an annual incidence of 3.9 cases of laboratory culture-confirmed tuberculosis (TB) per 100,000 population. Historical data shows that Australia's TB incidence rates of culture-confirmed TB have varied little in recent years, ranging from 3.9 to 4.1 cases per 100,000 population. The incidence rate continues to vary between States, reflecting differences in the distribution of persons belonging to high-risk categories for TB. The male to female ratio showed a slight increase to almost 1.3:1, but in keeping with previous years, males with culture-confirmed TB were older (median age group 45-49 years) than females (median age group 35-39 years), and approximately half of all pulmonary diagnoses involved positive microscopy. Lymphatic disease again accounted for almost 20% of the total cases, with 66% of cases being recorded in females. Approximately 9% of isolates, a decrease from 11% in 1996, had in vitro resistance to at least one of the four standard anti-tuberculosis drugs. Fourteen isolates were multi-drug resistant in 1997 compared with 15 in 1996. Overall, the data indicates a remarkably stable picture for TB in Australia. Commun Dis Intell 1999;23:349-353.