Is Acanthamoeba encephalitis an opportunistic infection?

Fifteen patients with granulomatous amebic encephalitis (GAE) resulting from Acanthomoeba were studied. GAE usually occurred in chronically ill and debilitated individuals, some of whom had received immunosuppressive therapy; none had a history of swimming or had been involved in aquatic activities. In contrast, primary amebic meningoencephalitis (PAM) caused by Naegleria fowleri usually occurs in healthy, young individuals who are exposed to polluted waters. The results of this study confirm that opportunistic amebic infections occur with increased frequency in patients treated with steroids, chemotherapeutic drugs, or broad-spectrum antibiotics. The mechanism of such infection may be depressed cell-mediated immunity.