Neurological Melioidosis: Seven Cases from the Northern Territory of Australia

Abstract

Pseudomonas pseudomallei, which causes melioidosis, is most commonly associated with pulmonary infection. We describe seven patients who developed a neurological syndrome as the predominant manifestation of melioidosis: this syndrome was characterized by peripheral motor weakness (mimicking Guillain-Barré syndrome), brain-stem encephalitis, aseptic meningitis, and respiratory failure. Neurological melioidosis occurred in the absence of demonstrable foci of infection in the central nervous system (CNS) in five of six patients whose cerebrospinal fluid was available for culture. Computed tomography and magnetic resonance imaging of the brain and spinal cord of these patients were not suggestive of pyogenic infection, although the latter procedure detected brain-stem encephalitis. Autopsy findings in one case confirmed brain-stem encephalitis without evidence of direct bacterial infection. The clinical presentation of neurological melioidosis includes features of an exotoxin-induced neurological syndrome, with profound neurological disease occurring in the absence of apparent direct infection of the CNS. This syndrome appears to be a newly recognized clinical presentation of melioidosis.

Melioidosis: Epidemiology, Pathophysiology, and Management

“…Small numbers of children with a similar syndrome have been recognized in Thailand (365). Cultures of cerebrospinal fluid were positive in only one of seven cases, with monocytic pleocytosis the most common finding (488). This should be distinguished from more focal suppurative infections involving the central nervous system, which have been well described (55,62,66,332,438,459).…”

A cluster of melioidosis cases from an endemic region is clonal and is linked to the water supply using molecular typing of Burkholderia pseudomallei isolates.

“…This would support neurological melioidosis being caused in these cases by direct bacterial invasion of the nervous system rather than it being the result of toxininduced damage from B. pseudomallei strains producing a neurotropic exotoxin. 13 None of the eight environmental isolates utilized arabinose on API 20 NE testing. Arabinose assimilation differentiates between pathogenic strains of B. pseudomallei, which do not assimilate arabinose (Ara-), and nonvirulent B. pseudomallei-like organisms, which assimilate arabinose (Araϩ).…”

Pathogens Penetrating the Central Nervous System: Infection Pathways and the Cellular and Molecular Mechanisms of Invasion

“…CSF shows high protein, normal or slightly decreased glucose, and, most notably, a pleocytosis with lymphocytes usually predominant. Bulbar palsy and decreased respiratory drive often necessitate ventilation, which may be required for many weeks (56,(59)(60)(61)(62). In northern Australia, patients infected with the flavivirus Murray Valley encephalitis virus can present with clinical features indistinguishable from those seen with melioidosis encephalomyelitis.…”