Central nervous system infections by members of the Pseudallescheria boydii species complex in healthy and immunocompromised hosts: epidemiology, clinical characteristics and outcome.

Infections caused by members of the Pseudallescheria boydii species complex are currently among the most common mould infections. These fungi show a particular tropism for the central nervous system (CNS). We reviewed all the available reports on CNS infections, focusing on the geographical distribution, infection routes, immunity status of infected individuals, type and location of infections, clinical manifestations, treatment and outcome. A total of 99 case reports were identified, with similar percentage of healthy and immunocompromised patients (44% vs. 56%; P = 0.26). Main clinical types were brain abscess (69%), co-infection of brain tissue and/or spinal cord with meninges (10%) and meningitis (9%). The mortality rate was 74%, regardless of the patient's immune status, or the infection type and/or location. Cerebrospinal fluid culture was revealed as a not very important tool as the percentage of positive samples for P. boydii complex was not different from that of negative ones (67% vs. 33%; P = 0.10). In immunocompetent patients, CNS infection was preceded by near drowning or trauma. In these patients, the infection was characterised by localised involvement and a high fatality rate (76%). In contrast, CNS infection in immunocompromised patients was presented as rapidly progressive disseminated lesions at various degrees of evolution. Major risk factors for CNS infection were the aspiration of polluted water in near-drowning episodes in immunologically intact patients and medical immunosuppression in the remaining patient groups. As the therapeutic options were poor, the treatment was difficult in general and the prognosis was poor.