J. De Jonckheere

Naegleria lovaniensis new species: isolation and identification of six thermophilic strains of a new species found in association with Naegleria fowleri.

Abstract Six Naegleria strains, isolated previously in association with N. fowleri from thermal waters, were studied to further determine their antigenic relationship to N. fowleri and other Naegleria species. Results of immunofluorescent antibody and immunoelectrophoretic studies clearly established the antigenic divergence of the variants from N. fowleri, N. gruberi, and N. jadini. The variants were further distinguished from known Naegleria species by several ultrastructural characteristics, which included the complete enclosure of their nuclei with one or several layers of rough endoplasmic reticulum (RER) and extrusion of their nuclear material. Extruded nuclear material was observed in the cytoplasm completely sequestered by cisternae of the RER. The variants were also shown to be sensitive to agglutination induced by concanavalin A but not by wheat germ agglutinin. Based on the differences in the antigenicity, morphology, and lectin sensitivity between these six variants and established Naegleria species, we proposed that they should be established as a new species.

The effect of thermal pollution on the distribution of Naegleria fowleri

The distribution in the environment of Naegleria fowleri, the causal agent of primary amoebic meningoencephalitis has been investigated in this study. N. fowleri was isolated only from a thermally polluted canal. These amoebaflagellates were not isolated from another thermally polluted canal in the neighbourhood indicating that, apart from high temperature, other factors are involved in the selective proliferation of N. fowleri. This species was absent in all other samples originating from two canals, a stream, two lakes, several reservoirs and slow sandfilters of a water supply service and also a water distribution network. Many other amoebae able to grow at 42 degrees C. were found in different places. Most of the N. fowleri strains isolated were not virulent for mice, although they showed all the characteristics of the pathogenic strains.

Hospital hydrotherapy pools treated with ultra violet light: bad bacteriological quality and presence of thermophilic Naegleria.

The microbiological quality of eight halogenated and two u.v.-treated hydrotherapy pools in hospitals was investigated. The microbiological quality of halogenated hydrotherapy pools was comparable to halogenated public swimming pools, although in some Pseudomonas aeruginosa and faecal pollution indicators were more frequent due to bad management. On the other hand u.v.-treated hydrotherapy pools had very bad microbiological quality. Apart from faecal pollution indicators, P. aeruginosa was present in very high numbers. Halogenated hydrotherapy pools were not highly contaminated with amoebae, and Naegleria spp. were never detected. On the other hand u.v.-treated pools contained very high numbers of thermophilic Naegleria . The Naegleria isolates were identified as N. lovaniensis , a species commonly found in association with N. fowleri . Isoenzyme analysis showed a different type of N. lovaniensis was present in each of two u.v.-treated pools.

Comparative protein patterns of three thermophilic nonpathogenic Naegleria isolates and two Nageleria fowleri strains by isoelectric focusing

Abstract The protein composition of the soluble cellular extracts of 5 different strains of thermophilic Naegleria , comprising 2 pathogenic N. fowleri and 3 nonpathogenic Naegleria isolates, have been studied by isoelectric focusing on polyacrylamide gels. The two pathogenic N. fowleri strains, although originating from very different sources, show an identical protein pattern, and are easily differentiated by several characteristic bands from the group of thermophilic nonpathogenic Naegleria sp. The latter, closely related to one another, correspond to the new species N. lovaniensis . Besides being a practical identification method for Naegleria fowleri , isoelectric focusing seems to be an excellent method for investigating the taxonomy of the genus Naegleria .

Identifying new vahlkampfiid amoebae by ITS and 5.8S ribosomal DNA sequencing

Small subunit ribosomal DNA (SSU rDNA) comparisons have revealed that not only species but even genus identification based on morphology is unreliable in the family Vahlkampfiidae, and SSU rDNA sequences have been used to redefine vahlkampfiid genera. However, it is time consuming to use SSU rDNA sequences for species identification. The ITS region (including the 5.8S rDNA) has the advantage that it is much shorter than the SSU rDNA and thus easier and quicker to obtain. Initially, 29 strains of 13 species belonging to seven vahlkampfiid genera were investigated. It was found that each species has a specific ITS sequence, which appears to be conserved within a species. The same had previously been found in the vahlkampfiid genus Naegleria. Consequently, we have demonstrated that the ITS region (including the 5.8S rDNA) can be used to identify vahlkampfiid amoebae. In the current investigation, the ITS sequences of 16 undescribed vahlkampfiid isolates were determined. Based on these sequences, seven isolates were identified as belonging to described species, while nine represent six new species. Four of the new species belong to the genus Tetramitus, and one each to the genera Vahlkampfia and Paravahlkampfia.