Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 1998-1999: report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collected and analysed laboratory data on new diagnoses of infection with Mycobacterium tuberculosis complex in 1998 and 1999. Totals of 700 and 760 cases were identified, representing annual reporting rates of 3.7 and 4.0 cases of laboratory confirmed tuberculosis (TB) per 100,000 population in the years 1998 and 1999 respectively. Australia's TB reporting rates have varied little in the past decade, ranging from 3.7 to 4.1 cases per 100,000 population. Reporting rates vary between States, reflecting differences in the distribution of persons in 'high-risk' categories for TB. The male:female ratio decreased to almost 1:1. The median age for males with culture-confirmed TB is in the 45-49 age group; for females, the median is in the 35-39 age group. Pulmonary disease was diagnosed in 63 per cent of cases whereas disease of lymph nodes accounted for 21 per cent of all cases. Children have the lowest rates of culture-confirmed TB; males in the older age groups have the highest rates. Microscopy was positive for 60 per cent of culture-positive sputa, and for approximately 45 per cent of bronchoscopy specimens. The frequency of multi-drug resistance (less than 1%) was slightly lower than in previous years.