Melioidosis in New Caledonia: a dominant strain in a transmission hotspot

Area of Science:

• Infectious Diseases
• Microbiology
• Epidemiology

Background:

• Melioidosis is caused by Burkholderia pseudomallei, a bacterium endemic in Southeast Asia and northern Australia.
• Sporadic cases of melioidosis have been reported in New Caledonia since 2005.
• Understanding the epidemiology of melioidosis in New Caledonia is crucial due to its severe presentation and potential for fatalities.

Purpose of the Study:

• To investigate the epidemiology of melioidosis in New Caledonia.
• To compare local Burkholderia pseudomallei strains with those from endemic regions.
• To identify potential sources and transmission patterns of melioidosis in New Caledonia.

Main Methods:

• Retrospective analysis of 19 melioidosis cases diagnosed in New Caledonia since 1999.
• Comparison of clinical data and bacterial isolates from New Caledonian patients with data from endemic areas.
• Phylogenetic analysis of Burkholderia pseudomallei strains to identify clonal groups and transmission hotspots.

Main Results:

• Nineteen cases of melioidosis were diagnosed in New Caledonia between 1999 and the study period.
• Most cases were severe, characterized by frequent bacteremia, with a fatality rate of 16% (3 deaths).
• A hotspot of transmission was identified, linked to a clonal group of Burkholderia pseudomallei phylogenetically related to Australian strains, alongside sporadic cases with non-clonal strains.

Conclusions:

• Melioidosis represents a significant public health concern in New Caledonia, with a high proportion of severe cases and fatalities.
• The identification of a specific clonal group suggests localized transmission, potentially linked to environmental factors or specific introduction events.
• Further research is needed to elucidate the precise transmission dynamics and environmental reservoirs of Burkholderia pseudomallei in New Caledonia to inform prevention and control strategies.