Random amplified polymorphic DNA profiles as a tool for the characterization of Brazilian keratitis isolates of the genus Acanthamoeba

Alves, João M. P.; Gusmao, C X; Teixeira, Marta Maria Geraldes; Freitas, Denise de; Foronda, Annette Silva; Affonso, Heloiza T.

doi:10.1590/s0100-879x2000000100003

Cited by 37 publications

(25 citation statements)

References 23 publications

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“…Thus, a unique Acanthamoeba intronless sequence of 2,157 bp was obtained. At BLAST, our sequence revealed almost identical (99.2) to the strain U/HC1, isolated from a human keratitis in Brazil, of undefined genotype (Alves et al 2000). Other closest relatives were strains of genotype T13, showing sequence identity of 94%, while following entries in the BLAST all showed sequence identity values <93%.…”

Section: Resultsmentioning

confidence: 72%

“…Pairwise similarity value between the group U/HC1 and cvX and the T13 strains was 93.6-94.6% (dissimilarity 5.4-6.4%). 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).…”

Section: Resultsmentioning

confidence: 99%

“…'polyphaga' ATCC 30872, from freshwater (Alves et al 2000); Acanthamoeba sp. strains SE2-6F, E-5C and OB3b-3A, from rice soil (Murase and Frenzel 2008); and Acanthamoeba sp.…”

Section: Resultsmentioning

confidence: 99%

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

Corsaro

Venditti²

2010

Parasitol Res

104

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Acanthamoeba are widespread free-living amoebae, able to cause infection in animals, with keratitis and granulomatous encephalitis as major diseases in humans. Recent developments in the subgenus classification are based on the determination of the nucleotide sequence of the 18S rDNA. By this mean, Acanthamoeba have been clustered into 15 sequence types or genotypes, called T1 to T15. In this study, we analysed near full 18S rDNA of an Acanthamoeba recovered from an environmental sample and various unidentified Acanthamoeba sequences retrieved from GenBank. We provided phylogenetic evidence for a new genotype, which we proposed to name T16.

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Section: Resultsmentioning

confidence: 72%

Section: Resultsmentioning

confidence: 99%

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

Corsaro

Venditti²

2010

Parasitol Res

104

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“…Subclinical infections caused by these protozoa are probably common among healthy individuals, in whom protozoa harbored in the nose and throat can, in weaker periods, behave as facultative parasites [5,6]). In Brazil, cases of human diseases caused by these amoebae have been described [7][8][9][10] derived from water [11][12][13][14] and dust from external environments [15,16]. The few reports of FLA occurring in internal environments all involve hospitals [1,18].…”

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confidence: 99%

Prevalence of potentially pathogenic free-living amoebae from Acanthamoeba and Naegleria genera in non-hospital, public, internal environments from the city of Santos, Brazil

et al. 2009

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Acanthamoeba and Naegleria species are free-living amoebae (FLA) found in a large variety of natural habitats. The prevalence of such amoebae was determined from dust samples taken from public non-hospital internal environments with good standards of cleanliness from two campuses of the same University in the city of Santos (SP), Brazil, and where young and apparently healthy people circulate. The frequency of free-living amoebae in both campuses was 39% and 17% respectively, with predominance of the genus Acanthamoeba. On the campus with a much larger number of circulating individuals, the observed frequency of free-living amoebae was 2.29 times larger (P< 0.00005). Two trophozoite forms of Naegleria fowleri, are the only species of this genus known to cause primary amoebian meningoencephalitis, a rare and non-opportunistic infection. We assume that the high frequency of these organisms in different internal locations represents some kind of public health risk.

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“…The molecular analyses thus far suggest that 15 or more genotypes exist, designated T1, T2, etc. (1,9,11,12,24,27,29). Characterization of genotypes is an active area of investigation, since it is dependent upon the statistical criteria employed to distinguish genotypes and the expanding number of analyzed isolates.…”

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confidence: 99%

Identification and Distribution of Acanthamoeba Species Genotypes Associated with Nonkeratitis Infections

Booton¹,

et al. 2005

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Acanthamoeba is a free-living protozoan genus found in a wide variety of natural habitats, including water, soil, and air. Pathogenic isolates of Acanthamoeba are medically relevant as the causative agent of sight-threatening Acanthamoeba keratitis (AK), serious infections of other organs, and fatal granulomatous amebic encephalitis. Previous work employing DNA sequences of nuclear and mitochondrial small-subunit rRNA genes (SSU rRNA genes) determined the genotypic diversity of Acanthamoeba and found that many named species of Acanthamoeba are associated with particular genotypes. These studies also concluded that nearly all AK infections result from a single molecular genotype: T4. Here, we asked whether Acanthamoeba clinical isolates from non-AK infections are also associated with particular genotypes. DNA sequence determination of nuclear SSU rRNA genes was employed for genotypic identification of 29 isolates of Acanthamoeba from non-AK infections. Sequence analysis demonstrates that T4 is the predominant genotype in non-AK infections, including those in brain, cerebrospinal fluid, nasal passages, skin, and lung. Rare genotypes (T1, T10, and T12) have been isolated from brain infections. We conclude that genotype T4 is the primary genotype in non-AK Acanthamoeba infections, as was the case in AK infections. However, the genotypes that were isolated from brains have not been observed in environmental isolates of Acanthamoeba, and their natural ecological niche is unknown.The genus Acanthamoeba is a group of nearly 25 named species that has a worldwide distribution. Members of Acanthamoeba are naked (i.e., lacking tests, walls, or tecta with openings), free-living amebae that inhabit a wide range of natural ecological niches, including fresh and brackish water, beach sand, soil, air, etc. (4, 13, 16, 17). Acanthamoeba also has been isolated from humans and animals (16,18). In addition to its natural distribution, Acanthamoeba can be opportunistically pathogenic, being identified as the causative agent of a painful and sight-threatening infection of the cornea, Acanthamoeba keratitis (AK) (22). These infections can occur in otherwise healthy, nonimmunocompromised individuals. In developed countries, AK infections are usually associated with contact lens wear. Improper sterilization procedures have been identified as the cause of a large percentage of such AK infections (2, 22, 25). In developing nations, AK infections are not generally associated with contact lens wear; by contrast, most cases are the result of ocular trauma (6, 23).Acanthamoeba is also responsible for life threatening infections in patients with immunodeficiency disease. These include documented infections of the skin, nasal passages, lung, and brain (16,17,18,19). In the brain, Acanthamoeba causes a severe encephalitis termed granulomatous amebic encephalitis, which is nearly always fatal (18). Variations in the pathogenicity of different Acanthamoeba strains have been recognized in laboratory studies, but the relevance of these results to hum...

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Random amplified polymorphic DNA profiles as a tool for the characterization of Brazilian keratitis isolates of the genus Acanthamoeba

Cited by 37 publications

References 23 publications

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

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

Prevalence of potentially pathogenic free-living amoebae from Acanthamoeba and Naegleria genera in non-hospital, public, internal environments from the city of Santos, Brazil

Identification and Distribution of Acanthamoeba Species Genotypes Associated with Nonkeratitis Infections

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