The causative agent of melioidosis is

• A. Burkholderia cepacia
• B. Burkholderia pseudomallei
• C. Moraxella catarrhalis
• D. Stenotrophomonas maltophilia

Answer: (B)

Melioidosis is an infection acquired from soil and surface water in tropical regions, and the organism responsible is Burkholderia pseudomallei. This Gram-negative bacillus is environmental and can cause a wide spectrum of disease, from localized abscesses to septicemia, which is why it is tied specifically to this condition. The other bacteria listed are associated with different infections or settings: Burkholderia cepacia mainly affects people with cystic fibrosis or exposed to healthcare environments; Moraxella catarrhalis is a common respiratory pathogen; Stenotrophomonas maltophilia is a known opportunistic pathogen in nosocomial infections. Thus, Burkholderia pseudomallei is the best answer for melioidosis.