Genotyping of Acanthamoeba spp. isolated from patients with granulomatous amoebic encephalitis.
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ABSTRACT:
SUBMITTER: Megha K
PROVIDER: S-EPMC6362713 | biostudies-literature | 2018 Oct
REPOSITORIES: biostudies-literature
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Genotyping of <i>Acanthamoeba</i> spp. isolated from patients with granulomatous amoebic encephalitis.
Megha Kirti K Sehgal Rakesh R Khurana Sumeeta S
The Indian journal of medical research 20181001 4
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Project description:Acanthamoeba amoebae of genotype T2 were identified as the causative agent of Acanthamoeba skin lesions and granulomatous amoebic encephalitis (GAE) in a human immunodeficiency virus-negative patient with underlying tuberculosis. To our knowledge this, is the first case of GAE involving genotype T2.
| S-EPMC2224275 | biostudies-literature
Project description:Granulomatous amebic encephalitis (GAE) caused by Acanthamoeba is a rare infection with central nervous system (CNS) involvement usually with fatal consequences. Currently, information regarding GAE in children is scarce and is limited only to case reports and case series. A 13-year-old immunocompetent male patient with a 6-month history of progressive and intermittent headaches presented to our institution. One week before hospital admission, the patient showed signs of CNS involvement. Magnetic resonance imaging revealed multiple lesions with supra- and infratentorial cerebral abscesses. An empiric treatment with combined antibiotics was given, but the patient died after 20 days of hospital stay. A postmortem diagnosis confirmed GAE. Although it is a rare disease in pediatric patients, GAE should be considered in children with a chronic history of fever, headache, and vomiting with CNS involvement.
| S-EPMC8274766 | biostudies-literature
Project description: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.
| S-EPMC4977702 | biostudies-literature
Project description:Acanthamoeba spp. are free-living amoebae that are ubiquitous in natural environments. They can cause cutaneous, nasopharyngeal, and disseminated infection, leading to granulomatous amebic encephalitis (GAE) in immunocompromised individuals. In addition, they can cause amoebic keratitis in contact lens wearers. Acanthamoeba GAE is almost always fatal because of difficulty and delay in diagnosis and lack of optimal antimicrobial therapy. Here, we report the description of an unusual strain isolated from skin and brain of a GAE patient. The amoebae displayed large trophozoites and star-shaped cysts, characteristics for acanthamoebas belonging to morphology Group 1. However, its unique morphology and growth characteristics differentiated this new strain from other Group 1 species. DNA sequence analysis, secondary structure prediction, and phylogenetic analysis of the 18S rRNA gene confirmed that this new strain belonged to Group 1, but that it was distinct from the other sequence types within that group. Thus, we hereby propose the establishment of a new species, Acanthamoeba byersi n. sp. as well as a new sequence type, T18, for this new strain. To our knowledge, this is the first report of a Group 1 Acanthamoeba that is indisputably pathogenic in humans.
| S-EPMC4618466 | biostudies-literature
Project description:BackgroundGranulomatous amoebic encephalitis (GAE) is a rare central nervous system infection caused by the Balamuthia mandrillaris or Acanthamoeba species. Diagnosis is challenging because of the non-specific clinical presentation, cerebrospinal fluid analysis, and radiological features. There is no effective treatment for GAE to date.Case presentationA 54-year-old male was admitted to hospital after experiencing acute onset of numbness and weakness on his left limb. Due to the initial consideration of intracranial tumor, surgical removal of the right parietal lesion was performed. However, the patient had a headache accompanied by diplopia, difficulty walking and a new lesion was found in the left occipital-parietal lobe two weeks after the first operation. High-throughput next-generation sequencing (NGS) detected the presence of high copy reads of the B. mandrillaris genome sequence in the patient's blood, cerebral spinal fluid (CSF), and brain tissue. Pathological investigation of the brain tissue showed granulomatous changes and amoebic trophozoite scattered around blood vessels under high magnification. The patient was re-operated due to developing progressive confusion caused by subfalcine herniation of the left cerebral hemisphere. The lesions of the right parietal lobe were obviously decreasing in size after the first surgery, and the lesions of the left occipital lobe and the sunfalcine herniation didn't ameliorate two months after the second surgery. The patient was transferred to local hospital for continuous treatment with sulfamethoxazole and azithromycin. After five months of the second surgery, the patient showed good recovery with mild headache.ConclusionsThis is the first report of a patient with B. mandrillaris encephalitis initially confirmed by NGS and have experienced two excisions, responding favorably to the combination of surgeries and medications. Early surgical resection of intracranial lesions combined with drug treatment may offer the chance of a cure.
| S-EPMC8760828 | biostudies-literature
Project description:IntroductionBalamuthia (B.) mandrillaris is a free-living amoeba that can cause rare yet fatal granulomatous amoebic encephalitis (GAE). However, efficacious treatment for GAE is currently unavailable, especially when genomic studies on B. mandrillaris are limited.MethodsIn this study, B. mandrillaris strain KM-20 was isolated from the brain tissue of a GAE patient, and its mitochondrial genome was de novo assembled using high-coverage Nanopore long reads and Illumina short reads.Results and discussionPhylogenetic and comparative analyses revealed a range of diversification in the mitochondrial genome of KM-20 and nine other B. mandrillaris strains. According to the mitochondrial genome alignment, one of the most variable regions was observed in the ribosomal protein S3 (rps3), which was caused by an array of novel protein tandem repeats. The repeating units in the rps3 protein tandem region present significant copy number variations (CNVs) among B. mandrillaris strains and suggest KM-20 as the most divergent strain for its highly variable sequence and highest copy number in rps3. Moreover, mitochondrial heteroplasmy was observed in strain V039, and two genotypes of rps3 are caused by the CNVs in the tandem repeats. Taken together, the copy number and sequence variations of the protein tandem repeats enable rps3 to be a perfect target for clinical genotyping assay for B. mandrillaris. The mitochondrial genome diversity of B. mandrillaris paves the way to investigate the phylogeny and diversification of pathogenic amoebae.
| S-EPMC10196457 | biostudies-literature
Project description:BackgroundGranulomatous amoebic encephalitis (GAE) is an infrequent and fatal infectious disease worldwide. Antemortem diagnosis in this condition is very difficult because clinical manifestations and neuroimaging are nonspecific.Case presentationA 60-year-old Japanese woman was admitted with a chief complaint of left homonymous hemianopsia. Brain-MRI showed extensive necrotizing lesions enhanced by gadolinium, in the right frontal lobe, right occipital lobe, and left parietal lobe. Epithelioid granulomas of unknown etiology were found in the biopsied brain specimens. Shotgun metagenomic sequencing using a next-generation sequencer detected DNA fragments of Balamuthia mandrillaris in the tissue specimens. The diagnosis of granulomatous amoebic encephalitis was confirmed using an amoeba-specific polymerase chain reaction and immunostaining on the biopsied tissues.ConclusionsShotgun metagenomics is useful for the diagnosis of central nervous system infections such as GAE wherein the pathogens are difficult to identify.
| S-EPMC8501540 | biostudies-literature
Project description:Acanthamoeba, a free-living amoeba, is widely distributed in the environment, water sources, soil, dust, and air. It can cause keratitis in contact lens wearers with poor hygiene and also fatal granulomatous amebic encephalitis (GAE) in immunocompromised hosts. The aim of this study was to gain some insights into the distribution and genotypes of the potentially pathogenic species of Acanthamoeba present in water sources in north of Iran. Total 43 Acanthamoeba species were isolated from 77 water samples taken from different water sources within the Mazandaran province in Northern Iran (Sari city and suburbs). Isolates were identified based on cyst and trophozoite morphological characteristics as well genetics. PCR fragments corresponding to the small-subunit 18S rRNA gene were sequenced for 20 of 43 positive isolates. The results revealed that 83.3% of sequenced isolates belonged to the T4 genotype and the rest belonged to the T2 genotype. Our results indicated that Acanthamoeba is widely distributed in Sari city. As the incidence in Iran of amoebic keratitis has increased in recent years, the exact estimation of the prevalence of this amoeba and its predominant genotype may play a crucial role in prevention of the disease. Sari city has several rivers, seashores, and natural recreational amenities, which attract visitors during the year. This is the first report of Acanthamoeba genotypes from water sources in Sari city, Mazandaran province of Iran, and the results suggest that more attention is needed to protect the visiting population and immunocompromised individuals.
| S-EPMC5040085 | biostudies-literature
Project description:This study aimed to investigate the presence and genotyping of Acanthamoeba spp., in the bronchoalveolar lavage fluid (BALF) of immunocompetent patients with chronic respiratory disorders (CRD). In this study, 211 BALF samples were collected from patients with CRD during the COVID-19 pandemic who were candidates for fiberoptic bronchoscopy (FOB) at Imam Khomeini Hospital, Sari, Mazandaran Province, northern Iran and investigated for Acanthamoeba spp., by PCR. A total of 211 FBAL samples were examined; 5 (5/211; 2.36%) were positive by using the PCR test for Acanthamoeba spp. According to sequence analysis, three strains belonged to the T4 genotype and one strain to the T2 genotype. Our data demonstrate that the presence of Acanthamoeba (T4 and T2) in BALF specimens of patients with respiratory infections. However, it is important to note that these findings may be merely accidental. Our findings suggest further investigation to fully understand the role of Acanthamoeba spp. in the pathogenesis of lung infections.
| S-EPMC9362591 | biostudies-literature
Project description:BackgroundAcanthamoeba spp. is opportunistic amoeba that resides in water, soil, and air. Some pathogenic genotypes of the genus of Acanthamoeba can cause granulomatous amoebic encephalitis (GAE) in people with a defective immune system. The parasite can also cause Acanthamoeba keratitis (AK) among contact lens users. This study was conducted to isolate and identify the Acanthamoeba genotypes in water resources in Lorestan province, western Iran.MethodsCollected 72 water samples from surface and groundwater (springs and aqueducts) in Lorestan province. Samples were filtered and cultured in non-nutrient 1.5% agar medium covered with Escherichia coli (E. coli) at 25 °C. DNA extraction was done and the PCR reaction was performed to detect the Acanthamoeba spp. The positive PCR products were sequenced to determine the genotypes of Acanthamoeba.ResultsOut of 72 examined water samples, 23.61% were positive for Acanthamoeba sp. by PCR. From PCR-positive samples, 8 (47.05%) samples were T4 genotypes and others were other Acanthamoeba genotypes (T1-T23). Therefore, approximately half of the genotypes belong to the pathogenic T4 genotype.ConclusionsThe water examined samples in western provinces of Iran have the potential risk factor for public health. Therefore, the efforts of healthcare providers are needed to identify, train, and prevention from human infections.
| S-EPMC10450349 | biostudies-literature