The Epidemiology of Melioidosis in Townsville, Australia

Background: Melioidosis in an infection caused by Burkholderia pseudomallei, an organism endemic to tropical and subtropical regions.

Methods: This study describes the epidemiology of melioidosis in Townsville, QLD, Australia, as well as clinical features, risk factors associated with the disease, the burden of infection on the Aboriginal and Torres Strait Islander (ATSI) community and patient outcomes over time.

Results: From 1997 to 2020, 128 patients were admitted to Townsville University Hospital. The total annual incidence of infection was 3.2 cases per 100 000 compared with 15.3 per 100 000 in the ATSI population. The majority of cases (n=82 [64%]) were male. Alcohol excess (55%) and diabetes mellitus (48%) were the most common risk factors. Bacteraemia occurred in 87 (70%) patients and pneumonia was the most common focus of infection in 84 (69%). The case fatality rate was 23%, with no difference for the ATSI population (6/32 [19%]). The presence of malignancy was the risk factor most associated with mortality (relative risk 2.7 [95% confidence interval 1.4-5.1], p=0.005).

Conclusions: The ATSI community was overrepresented in this study, however, there was no significant difference in adverse outcomes. The case fatality rate was higher than in other regions in Australia. This discrepancy may relate in part to the different risk groups seen in these settings coupled with potential organism variability.