Heterogeneity in cyst morphology within isolates of <i>Acanthamoeba</i> from keratitis patients in Thailand

Jongwutiwes, Somchai; Pariyakanok, Lalida; Charoenkorn, Malee; Yagita, Kenji; Endo, Tokiko

doi:10.1046/j.1365-3156.2000.00563.x

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…Acanthamoeba genotypes T2 to T4 and T11 have been found to cause keratitis, while genotypes T1, T4, T10, and T12 are responsible for GAE (2). Although both GAE and AK occurred in Thai patients and the organisms are widely distributed in water sources, little is known about genotypic distribution of acanthamoebae in this country (7,10,13).…”

mentioning

confidence: 99%

Identification of a Novel T17 Genotype of Acanthamoeba from Environmental Isolates and T10 Genotype Causing Keratitis in Thailand

Nuprasert¹,

Putaporntip²,

Pariyakanok

et al. 2010

J Clin Microbiol

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141

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mentioning

confidence: 99%

Identification of a Novel T17 Genotype of Acanthamoeba from Environmental Isolates and T10 Genotype Causing Keratitis in Thailand

Nuprasert¹,

Putaporntip²,

Pariyakanok

et al. 2010

J Clin Microbiol

Self Cite

141

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“…For the past decade, keratitis cases had increased dramatically parallel with the popularity of contact lens usage, hence, resulting in more reports of clinically confirmed cases in Southeast Asia. Acanthamoeba species was revealed to be the main cause of keratitis infection in raw water in Thailand [ 50 , 51 ] and Vietnam [ 52 ], in regards with water-related activities (i.e. swimming and diving) and accidental water-splashing.…”

Section: Discussionmentioning

confidence: 99%

Pathogenic waterborne free-living amoebae: An update from selected Southeast Asian countries

et al. 2017

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Data on the distribution of free-living amoebae is still lacking especially in Southeast Asian region. The aquatic environment revealed a high occurrence of free-living amoebae (FLA) due to its suitable condition and availability of food source, which subsequently causes infection to humans. A total of 94 water samples consisted of both treated and untreated from Laos (31), Myanmar (42), and Singapore (21) were investigated for the presence of pathogenic FLA. Each water sample was filtered and cultured onto non-nutrient agar seeded with live suspension of Escherichia coli and incubated at room temperature. Morphological identification was conducted for both trophozoites and cysts via microscopic stains (Giemsa and immunofluorescence). The presence of Naegleria-like structures was the most frequently encountered in both treated and untreated water samples, followed by Acanthamoeba-like and Vermamoeba-like features. To identify the pathogenic isolates, species-specific primer sets were applied for molecular identification of Acanthamoeba, Naegleria, and Vermamoeba. The pathogenic species of Acanthamoeba lenticulata and A. triangularis were detected from untreated water samples, while Vermamoeba vermiformis was found in both treated and untreated water samples. Our results suggested that poor water quality as well as inadequate maintenance and treatment might be the cause of this alarming problem since chlorine disinfection is ineffective in eradicating these amoebas in treated water samples. Regular monitoring and examination of water qualities are necessary in order to control the growth, hence, further preventing the widespread of FLA infections among the public.

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“…The clustering of the MU_AK into T4 monophyletic clade, could be explained that the 0.73% of genetic distances were remained lower than the 5% cut off value which is known to be characteristic of different genotype [11]. To our knowledge, few molecular studies of Acanthamoeba isolated in Thailand have been documented [18,19,36,37]. Clinically, genotypes T4 and T10 were reported to be responsible for Acanthamoeba keratitis cases, while only T4 was identified from a case of Acanthamoeba meningoencephalitis [18].…”

Section: Discussionmentioning

confidence: 99%

The First Acanthamoeba keratitis Case of Non-Contact Lens Wearer with HIV Infection in Thailand

et al. 2019

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Acanthamoeba keratitis (AK) is a rare sight-threatening corneal infection, often reporting from contact lens wearers. An asymptomatic human immunodeficiency virus (HIV)-infected Thai male without history of contact lens use complained foreign body sensation at his left eye during motorbike riding. He had neither specific keratitis symptoms nor common drugs responding, which contributed to delayed diagnosis. By corneal re-scraping, Acanthamoeba-like cysts were detected by calcofluor white staining and agar culture. The etiological agent obtained from the culture was molecularly confirmed by Acanthamoeba spp.-specific PCR, followed by DNA sequencing. The results from BLAST and phylogenetic analysis based on the DNA sequences, revealed that the pathogen was Acanthamoeba T4, the major genotype most frequently reported from clinical isolates. The infection was successfully treated with polyhexamethylene biguanide resulting in corneal scar. This appears the first reported AK case from a non-contact lens wearer with HIV infection in Thailand. Although AK is sporadic in developing countries, a role of free-living Acanthamoeba as an opportunistic pathogen should not be neglected. The report would increase awareness of AK, especially in the case presenting unspecific keratitis symptoms without clinical response to empirical antimicrobial therapy.

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Heterogeneity in cyst morphology within isolates of Acanthamoeba from keratitis patients in Thailand

Cited by 10 publications

References 17 publications

Identification of a Novel T17 Genotype of Acanthamoeba from Environmental Isolates and T10 Genotype Causing Keratitis in Thailand

Identification of a Novel T17 Genotype of Acanthamoeba from Environmental Isolates and T10 Genotype Causing Keratitis in Thailand

Pathogenic waterborne free-living amoebae: An update from selected Southeast Asian countries

The First Acanthamoeba keratitis Case of Non-Contact Lens Wearer with HIV Infection in Thailand

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