Identification of Acanthamoeba sp. in paraffin-embedded CNS tissue from an HIV+ individual by PCR.

The opportunistic pathogens, Acanthamoeba and Balamuthia, are the causative agents of the fatal central nervous system (CNS) infection granulomatous amoebic encephalitis. We report an infection of Acanthamoeba in an HIV+ individual. In the present case, multiple lesions were observed in the skin, brain, lung, liver, and bone. A polymerase chain reaction (PCR) assay specific for Acanthamoeba was positive on tissue from a brain biopsy that had been embedded in paraffin. This report demonstrates the need for the consideration of Acanthamoeba infections in HIV+ individuals with skin lesions and multiple lesions throughout the body with CNS involvement. The results of the present study demonstrate that opportunistic amoebic infections can be diagnosed by PCR from paraffin-embedded biopsy material.

Identification of a Naegleria fowleri membrane protein reactive with anti-human CD59 antibody.

Naegleria fowleri, the causative agent of primary amebic meningoencephalitis, is resistant to complement lysis. The presence of a complement regulatory protein on the surface of N. fowleri was investigated. Southern blot and Northern blot analyses demonstrated hybridization of a radiolabeled cDNA probe for CD59 to genomic DNA and RNA, respectively, from pathogenic N. fowleri. An 18-kDa immunoreactive protein was detected on the membrane of N. fowleri by Western immunoblot and immunofluorescence analyses with monoclonal antibodies for human CD59. Complement component C9 immunoprecipitated with the N. fowleri "CD59-like" protein from amebae incubated with normal human serum. In contrast, a gene or protein similar to CD59 was not detected in nonpathogenic, complement-sensitive N. gruberi amebae. Collectively, our studies suggest that a protein reactive with antibodies to human CD59 is present on the surface of N. fowleri amebae and may play a role in resistance to lysis by cytolytic proteins.

The identification of Naegleria fowleri from water and soil samples by nested PCR.

Naegleria fowleri is the causative agent of primary amebic meningoencephalitis (PAM), a disease of the central nervous system. Healthy humans sporadically become infected with N. fowleri and develop fatal PAM after recreational or work exposure to freshwater; accordingly, there is a need for monitoring the presence of pathogenic ameboflagellates in public freshwater. The present study was conducted to determine whether a nested PCR assay could be used for the detection of N. fowleri in freshwater habitats. Water samples were collected in Virginia, since Naegleria has been isolated previously in this state. Additionally, the occurrence of N. fowleri in samples from Connecticut was investigated since neither N. fowleri nor PAM has been reported from this region. PCR analysis demonstrated that two of four samples from Virginia were positive for N. fowleri without intervening culture while 15 of 86 samples from Connecticut were positive that had been enriched by culture. This constitutes the first report of N. fowleri from Connecticut waters. These results indicate that the PCR assay can be utilized to detect N. fowleri in water and soil collected from the environment.