Abstract
BackgroundAcanthamoeba spp. are free-living ubiquitous protozoans capable of causing Acanthamoeba meningitis/meningoencephalitis (AME) of the central nervous system in humans. Acanthamoeba spp. are divided into 20 different genotypes (T1–T20) on the basis of variation in nucleotide sequences of the 18S rRNA gene. The objective of this study was to identify the genotypes of Acanthamoeba spp. in patients of Acanthamoeba meningitis/meningoencephalitis (AME) using 18S rRNA gene-based PCR assay. The present study provides information regarding the involvement of the most prevalent and predominant genotype of Acanthamoeba spp. in Acanthamoeba meningitis/meningoencephalitis infections in India.MethodsCerebrospinal fluid (CSF) was collected from 149 clinically suspected Acanthamoeba meningitis/meningoencephalitis (AME) patients reporting to the outpatient department/causality services of the Neurosciences Centre, AIIMS, New Delhi, India during the past five years. Samples were inoculated onto 2 % non-nutrient agar plates overlaid with E. coli and incubated at 30 °C for 14 days. Among 149 suspected patients, ten were found culture-positive for Acanthamoeba spp. out of which six isolates were established in axenic culture for molecular analysis. DNA was isolated and a PCR assay was performed for amplification of the Diagnostic fragment 3 (DF3) (~280 bp) region of the 18S rRNA gene from axenic culture of six Acanthamoeba spp. isolates. Rns genotyping was performed on the basis of the variation in nucleotide sequences of DF3 region of the 18S rRNA gene.ResultsIn the phylogenetic analysis, all of the six Acanthamoeba spp. isolates were found to belong to genotype T4. The sequence homology search for these six isolates in the NCBI databank showed homology with the available strains of Acanthamoeba spp. The newly generated sequences are available in the GenBank database under accession numbers KT004416–KT004421.ConclusionsIn the present study, genotype T4 was found as the most prevalent and predominant genotype in Acanthamoeba meningitis/ meningoencephalitis infections. Hence further studies are needed to develop optimal therapeutic strategy against Acanthamoeba spp. of genotype T4 to combat against the infections.
Highlights
Acanthamoeba spp. are free-living ubiquitous protozoans capable of causing Acanthamoeba meningitis/meningoencephalitis (AME) of the central nervous system in humans
Among 149 suspected patients of Acanthamoeba meningitis/meningoencephalitis (6.71 %) cases were found culture positive, (7.38 %) cases were found PCR positive and 10 (6.71 %) cases were positive by both culture and PCR assay for Acanthamoeba spp
Nucleotide sequences for the Diagnostic fragment 3 (DF3) region produced a clear band of ~280 bp length when electrophoresed in 1.5 % agarose gel for all positive specimens (Fig. 3)
Summary
Acanthamoeba spp. are free-living ubiquitous protozoans capable of causing Acanthamoeba meningitis/meningoencephalitis (AME) of the central nervous system in humans. Acanthamoeba spp. are divided into 20 different genotypes (T1–T20) on the basis of variation in nucleotide sequences of the 18S rRNA gene. The objective of this study was to identify the genotypes of Acanthamoeba spp. in patients of Acanthamoeba meningitis/meningoencephalitis (AME) using 18S rRNA gene-based PCR assay. The present study provides information regarding the involvement of the most prevalent and predominant genotype of Acanthamoeba spp. in Acanthamoeba meningitis/meningoencephalitis infections in India. Acanthamoeba spp. are free-living ubiquitous protozoans capable of causing Acanthamoeba meningitis/meningoencephalitis (AME) of the central nervous system and fatal granulomatous amoebic encephalitis (GAE) of the brain in humans [1]. The clinical symptoms of AME resemble viral, bacterial or tubercular meningitis such as fever, headache, stiff neck, lethargy, vomiting, nausea, etc. With advancement of the disease, seizures, behavioural changes like diplopia, aphasia, ataxia, altered mental state and lethargy were seen as other major symptoms [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
