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Prevalence of Naegleria fowleri in Environmental Samples from Northern Part of India.

ABSTRACT: Naegleria fowleri the causative agent of Primary Amoebic Meningoencephalitis, is ubiquitously distributed worldwide in various warm aquatic environments and soil habitats. The present study reports on the presence of Naegleria spp. in various water bodies present in Rohtak and Jhajjar district, of state Haryana, India. A total of 107 water reservoirs were screened from summer till autumn (2012 and 2013). In order to isolate Naegleria spp. from the collected water samples, the water samples were filtered and the trapped debris after processing were transferred to non-nutrient agar plates already seeded with lawn culture of Escherichia coli. Out of total 107 water samples, 43 (40%) samples were positive by culture for free living amoeba after incubation for 14 days at 37°C. To identify the isolates, the ITS1, 5.8SrDNA and ITS2 regions were targeted for PCR assay. Out of total 43 positive samples, 37 isolates were positive for Naegleria spp. using genus specific primers and the most frequently isolated species was Naegleria australiensis. Out of 37 Naegleria spp. positive isolates, 1 isolate was positive for Naegleria fowleri. The sequence analysis revealed that the Naegleria fowleri strain belonged to Type 2.

SUBMITTER: Panda A

PROVIDER: S-EPMC4618853 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Prevalence of Naegleria fowleri in Environmental Samples from Northern Part of India.

Panda Ashutosh A Khalil Shehla S Mirdha Bijay Ranjan BR Singh Yogita Y Kaushik Samander S

PloS one 20151020 10

Naegleria fowleri the causative agent of Primary Amoebic Meningoencephalitis, is ubiquitously distributed worldwide in various warm aquatic environments and soil habitats. The present study reports on the presence of Naegleria spp. in various water bodies present in Rohtak and Jhajjar district, of state Haryana, India. A total of 107 water reservoirs were screened from summer till autumn (2012 and 2013). In order to isolate Naegleria spp. from the collected water samples, the water samples were ...[more]

PMID: 26484533

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Project description:Out of over 40 species of Naegleria, which are free-living thermophilic amebae found in freshwater and soil worldwide, only Naegleria fowleri infects humans, causing primary amebic meningoencephalitis (PAM), a typically fatal brain disease. To understand the population structure of Naegleria species and the genetic relationships between N. fowleri isolates and to detect pathogenic factors, we characterized 52 novel clinical and environmental N. fowleri genomes and a single Naegleria lovaniensis strain, along with transcriptomic data for a subset of 37 N. fowleri isolates. Whole-genome analysis of 56 isolates from three Naegleria species (N. fowleri, N. lovaniensis, and Naegleria gruberi) identified several genes unique to N. fowleri that have previously been linked to the pathogenicity of N. fowleri, while other unique genes could be associated with novel pathogenicity factors in this highly fatal pathogen. Population structure analysis estimated the presence of 10 populations within the three Naegleria species, of which 7 populations were within N. fowleri. The whole-nuclear-genome (WNG) phylogenetic analysis showed an overall geographical clustering of N. fowleri isolates, with few exceptions, and provided higher resolution in identifying potential clusters of isolates beyond that of the traditional locus typing. There were only 34 genes that showed significant differences in gene expression between the clinical and environmental isolates. Genomic data generated in this study can be used for developing rapid molecular assays and to conduct future population-based global genomic analysis and will also be a valuable addition to genomic reference databases, where shotgun metagenomics data from routine water samples could be searched for the presence of N. fowleri strains. IMPORTANCE N. fowleri, the only known Naegleria species to infect humans, causes fatal brain disease. PAM cases from 1965 to 2016 showed <20 cases per year globally. Out of approximately 150 cases in North America since 1962, only four PAM survivors are known, yielding a >97% case fatality rate, which is critically high. Although the pathogenesis of N. fowleri has been studied for the last 50 years, pathogenetic factors that lead to human infection and breaching the blood-brain barrier remain unknown. In addition, little is known regarding the genomic diversity both within N. fowleri isolates and among Naegleria species. In this study, we generated novel genome sequences and performed comparative genomic and transcriptomic analysis of a set of 52 N. fowleri draft genome sequences from clinical and environmental isolates derived from all over the world in the last 53 years, which will help shape future genome-wide studies and develop sensitive assays for routine surveillance.

Project description:BackgroundIn Malaysia, researchers and medical practitioners are unfamiliar with Naegleria infections. Thus little is known about the existence of pathogenic Naegleria fowleri, and the resultant primary amoebic meningoencephalitis (PAM) is seldom included in the differential diagnosis of central nervous system infections. This study was conducted to detect the presence of Naegleria species in various environmental samples.Methods/findingsA total of 41 Naegleria-like isolates were isolated from water and dust samples. All these isolates were subjected to PCR using two primer sets designed from the ITS1-ITS2 regions. The N. fowleri species-specific primer set failed to produce the expected amplicon. The Naegleria genus-specific primers produced amplicons of 408 bp (35), 450 bp (2), 457 bp (2) or 381 bp (2) from all 41 isolates isolated from aquatic (33) and dust (8) samples. Analysis of the sequences from 10 representative isolates revealed that amplicons with fragments 408, 450 and 457 bp showed homology with non-pathogenic Naegleria species, and 381 bp showed homology with Vahlkampfia species. These results concurred with the morphological observation that all 39 isolates which exhibited flagella were Naegleria, while 2 isolates (AC7, JN034055 and AC8, JN034056) that did not exhibit flagella were Vahlkampfia species.ConclusionTo date, pathogenic species of N. fowleri have not been isolated from Malaysia. All 39 isolates that produced amplicons (408, 450 and 457 bp) from the genus-specific primers were identified as being similar to nonpathogenic Naegleria. Amplicon 408 bp from 5 representative isolates showed 100% and 99.7% identity to Naegleria philippinensis isolate RJTM (AM167890) and is thus believed to be the most common species in our environment. Amplicons 450 bp and 457 bp were respectively believed to be from 2 new species of Naegleria, since representative isolates showed lower homology and had a longer base pair length when compared to the reference species in the Genbank, Naegleria schusteri (AJ566626) and Naegleria laresi (AJ566630), respectively.

Dataset Information

Prevalence of Naegleria fowleri in Environmental Samples from Northern Part of India.

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Prevalence of Naegleria fowleri in Environmental Samples from Northern Part of India.

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