Abstract

Background Melioidosis, caused by Burkholderia pseudomallei, poses a significant health risk in tropical and subtropical regions. The disease is endemic in Southeast Asia, including the Lao PDR (Laos), where the first case was confirmed in 1999. Although diagnostic improvements have led to increased identification of patients, comprehensive clinical and epidemiological data on melioidosis in Laos remain limited. Methods We conducted a 21-year prospective study (1999–2020) at Mahosot Hospital and other primary-tertiary hospitals in Vientiane Capital and surrounding provinces. Data were collected for all culture-confirmed melioidosis patients, including demographics, clinical presentations, laboratory findings, and outcomes. The epidemiological and clinical features of melioidosis patients were identified and described. Results A total of 1744 patients were culture-positive for B. pseudomallei. The majority (77.9%) were adults (aged ≥ 15 years), with a median age of 50 years (IQR 40–60) for adults, and 6 years ,(IQR 4–9) for children (aged <15 years). Seventy-four percent of infections occurred during the rainy season. Diabetes, including new admission hyperglycaemia, was a major associated co-factor, affecting 48.7% of patients. Chronic comorbidities were present in 46.7% of the cohort and were associated with disseminated disease and higher case-fatality rates (CFR). The overall CFR was 28.9% (34.9% among adults and 9.2% among children) and was higher in older patients, those with disseminated disease, and those with chronic multimorbidity. Patients with a shorter duration of illness before admission had higher CFRs, the highest CFR (42.4%) was seen in those admitted within 7 days of symptom onset, consistent with greater disease severity on hospital arrival. Conclusions Melioidosis is endemic in Lao PDR, with high infection and case fatality rates, particularly among vulnerable individuals. Early detection, improved diagnostics and public health interventions are essential to reduce incidence and improve disease outcomes, especially for those with chronic conditions like diabetes. Expanding diagnostic facilities and raising awareness among healthcare workers in remote areas for both melioidosis and diabetes are crucial steps forward.