Meropenem treatment failure in severe melioidosis despite in vitro susceptibility: A case report.

Burkholderia pseudomallei causes melioidosis, a potentially life-threatening infection that can rapidly progress to septic shock and multi-organ failure if not promptly recognized and treated. Current international guidelines recommend meropenem as first-line therapy for severe melioidosis, whereas prolonged oral eradication therapy is essential to prevent relapse. We report a 39-year-old man with diabetes mellitus and chronic hepatitis B who initially improved on intravenous ceftazidime for disseminated melioidosis, but relapsed after an inadequate eradication phase consisting of only one week of oral amoxicillin-clavulanate. During the second admission, he presented with septic shock and multiple deep abscesses. He initially stabilized on combination therapy including meropenem and ceftazidime, but deteriorated after de-escalation to meropenem monotherapy despite repeated in vitro susceptibility. Clinical improvement occurred after reintroduction and continuation of high-dose ceftazidime together with drainage of accessible abscesses. This case highlights that apparent clinical failure on meropenem monotherapy may be confounded by inadequate eradication therapy, incomplete source control, borderline baseline susceptibility, and possible pharmacokinetic factors. It also underscores the need to interpret in vitro susceptibility cautiously in severe relapsed melioidosis.