Isolation and genotyping of potentially pathogenic Acanthamoeba and Naegleria species from tap-water sources in Osaka, Japan

Abstract

Here, we carried out a survey to determine the prevalence of free-living amoebae (FLA) in tap-water sources from rivers and water treatment plants located in Osaka Prefecture, Japan. A total of 374 raw water samples were collected from 113 sampling points. The samples were filtrated and transferred to non-nutrient agar plates seeded with a heat-killed suspension of Escherichia coli and incubated for 2 to 7 days at 30 degrees C or 42 degrees C. The plates were examined by microscopy to morphologically identify FLA families, and polymerase chain reaction and sequence analysis were then performed to define the species of the detected Naegleria and Acanthamoeba isolates. A total of 257 of 374 samples (68.7%) were positive for FLA by microscopy, and among these there were 800 FLA isolates, including Acanthamoeba and Naegleria species. Sequence analysis identified five Acanthamoeba spp. isolates of the known pathogenic T4 genotype and 43 Naegleria australiensis isolates, a reported pathogen to mice and also of concern as a potential pathogen to humans. Our results suggest a wide distribution of FLA, including potential pathogenic species, in tap-water sources of western Japan.

Comparative analyses of different genetic markers for the detection of Acanthamoeba spp. isolates

“…During the last few years, molecular techniques (PCR) are increasingly being used in the identification of the genotype (Booton et al 2005, Caumo et al 2009, Edagawa et al 2009, Goldschmidt et al 2012, Howe et al 1997, Itahashi et al 2011, Jain and Tilak 2011, Laummaunwai et al 2012, Le Calvez et al 2012. Our results confirmed the usefulness of PCR for the early, rapid and sensitive diagnosis of pathogenic Acanthamoeba spp.…”

Phylogenetic evidence for a new genotype of Acanthamoeba (Amoebozoa, Acanthamoebida)

“…Following the criterion of a 5% of dissimilarity (Stothard et al 1998), the group U/HC1 and cvX represents a new genotype, from keratitis sample (Alves et al 2000) and freshwater (this study), for which we proposed the label T16. The T13 is closely related to but clearly distinct from T16, and comprises both ocular (Fritsche et al 1993) and environmental strains (Horn et al 1999;Edagawa et al 2009). …”

Assessment of Knowledge of Medical Students on an Important Health Issue Neagleria Flowri Infection at a Medical College of Karachi, Pakistan

“…As it is shown in the study that most of the respondents knew that Neaglaeria is an amoeba and it is the causative agent of Primary Amoebic meningoencephalitis. It is well established that the organism enters the brain through the cribriform plate first by entering the nose and further research reveals that Neaglaeria infection hence cannot be caused by drinking water [9]. Knowledge assessed among final year medical students 97.9% was much higher than the students of first year MBBS which was 32% regarding its mode of transmission being primarily through the nasal route.…”