Melioidosis in Mali: a retrospective observational study.

BACKGROUND Melioidosis is a neglected tropical bacterial infection with a high mortality rate caused by the Gram-negative soil bacterium Burkholderia pseudomallei. Although the disease is increasingly recognised in Asian and Pacific regions, the situation in Africa is characterised by a scarcity of data and great uncertainty regarding the disease burden and distribution. Here, we aimed to report cases of melioidosis in children younger than 5 years in Mali, where no confirmed melioidosis had been reported previously. METHODS Médecins Sans Frontières maintains a paediatrics programme in Koutiala, Mali, for children younger than 5 years, including a microbiology laboratory. Between January 2018, and September 2021, biochemical characteristics of bacterial isolates suggested the presence of B pseudomallei in clinical samples from children admitted with severe signs of infection. Isolated strains were characterised by whole genome sequencing. Clinical data on the course and outcome of confirmed melioidosis cases were retrospectively analysed from the hospital records. FINDINGS 31 melioidosis cases of children younger than 5 years were confirmed. 15 (48%) cases were in infants aged 12 months or younger. B pseudomallei-positive samples included 28 blood cultures, two pleural fluids, and one pus sample. Of 19 patients with available outcome data, 12 (63%) died. Phylogenetic analysis of the B pseudomallei isolates revealed high genetic diversity suggesting long-standing persistence of the bacterium in this region. We estimated an annual melioidosis incidence of 8·8 per 100 000 (95% CI 5·7-11·9) in the paediatric population and the derived 15·5 per 100 000 (10·0-20·8) for the overall population. INTERPRETATION This is, to the best of our knowledge, the first case series reported in Mali and the largest cohort of melioidosis cases ever reported in Africa. Our annual incidence estimates suggest that melioidosis is a significant public health problem in this part of Africa. These findings clearly highlight the need for improved diagnostics and observational studies to learn more about the African melioidosis burden. They also support the inclusion of melioidosis in national health strategies to inform surveillance and empiric treatment protocols. As melioidosis is resistant to common empirical antibiotic regimens, these measures are essential to reduce the high mortality rate. FUNDING None. TRANSLATION For the French translation of the abstract see Supplementary Materials section.