Acanthamoeba of three morphological groups and distinct genotypes exhibit variable and weakly inter-related physiological properties

Possamai, Cynara Oliveira; Loss, Ana Carolina; Costa, Adriana Oliveira; Falqueto, Aloísio; Furst, Cinthia

doi:10.1007/s00436-018-5824-8

Cited by 18 publications

(14 citation statements)

References 48 publications

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“…Contrary to T4, these genotypes have rarely been found associated with AK [12, 27–30]. Furthermore, in South America, genotype T11 has previously been reported only from the environmental samples, so this is the first report of this genotype being isolated from AK patients; it is also the first report of genotype T2 circulating in this area [26, 31–33]. It is worth mentioning that the sequences of genotype T11 reported from the environmental strains in Chile are different from those isolated from AK patients [26].…”

Section: Discussionmentioning

confidence: 98%

Genotypic diversity of Acanthamoeba strains isolated from Chilean patients with Acanthamoeba keratitis

et al. 2019

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BackgroundAcanthamoeba spp. are the causative agents of a severe keratitis occurring mainly in contact lens wearers. The genus comprises more than 24 species that are currently divided into 20 different genotypes (T1-T20) according to sequence variations in the 18S rRNA gene. The objective of this study was to identify the genotypes and sub-genotypes of Acanthamoeba isolates collected at the Parasitology Laboratory of the Public Health Institute of Chile, the only laboratory in the country where Acanthamoeba screening is performed. This is the first report of genotypic identification of clinical isolates of Acanthamoeba in Chile and one of the few in South America.ResultsIn this study, 114 Acanthamoeba isolates from 76 Acanthamoeba keratitis patients, obtained between 2005–2016, were genotyped. T4 was the predominant genotype; T2 and T11 genotypes, which are scarcely reported worldwide, were also identified in Chilean patients (one and two patients, respectively). This is the first report of T2 and T11 genotypes isolated from Acanthamoeba keratitis patients in South America. It is also the first report of the T2 genotype circulating in this continent. Analysis of the diagnostic fragment 3 region of the 18S rRNA gene showed 24 T4 variants, with a predominance of the sub-genotype T4/A, followed by T4/B, T4/G, T4/C and T4/D. Bayesian analysis revealed three groups among the T4 variants: two well supported groups that included 12 and 7 sub-genotypes, respectively, and a weakly supported group that included 5 sub-genotypes. Most of the predominant T4 sub-genotypes belonged to the same group, which included 71.3% of the patients, while some minority variants lied mainly in the other two clusters.ConclusionsT2, T4 and T11 genotypes were predominantly isolated from the Acanthamoeba keratitis patients in Chile. Chilean predominant T4 sub-genotypes, which have also been reported worldwide, formed a separate cluster of the minority T4 variants. This study provides useful information about the predominant genotypes and subgenotypes that would be useful in selecting suitable strains to develop immunological and/or molecular diagnostic assays in Chile.Electronic supplementary materialThe online version of this article (10.1186/s13071-019-3302-5) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 98%

Genotypic diversity of Acanthamoeba strains isolated from Chilean patients with Acanthamoeba keratitis

et al. 2019

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“…ALX can be considered a pathogenic strain due to its clinical origin (AK case) and tolerance to high temperature and osmolarity (42 o C and 1 M; Duarte et al, 2013). Although from environmental origin, R2P5 is characterized as pathogenic: (1) it tolerates 40 o C and exerts cytopathogenicity to MDCK cells (Possamai et al, 2018), (2) it is classified as T1, an genotype eventually associated to GAE (Alsam et al, 2005; Sissons et al, 2006, (3) it secrets higher amounts of proteases than other Acanthamoeba , including some AK‐derived T4 strains (Cirelli et al, 2020). On the other hand, AR15 (genotype T11) is an environmental strain considered non‐pathogenic by some phenotypic parameters (Duarte et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…Four clinical and environmental strains of Acanthamoeba from distinct genotypes were used. Physiological characterization (osmo‐tolerance and thermo‐tolerance) and genotyping based on 18S rDNA were previously described (Duarte et al, 2013; Possamai et al, 2018; Table 1). Axenic cultures were growth at 32°C in PYG medium (20 g/L proteose peptone, 1 g/L yeast extract, 0.1 M glucose, 4 mM Mg 2 SO 4 , 0.4 mM CaCl 2 , 3.4 mM sodium citrate, 0.05 mM Fe (NH 4 ) 2 (SO 4 ) 2 and 2.5 mM of each of Na 2 HPO 4 and K 2 HPO 4 , pH 6.5) supplemented with 10 μg/ml of Enrofloxacin (Baytril®).…”

Section: Methodsmentioning

confidence: 99%

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Distinct immunomodulatory properties of extracellular vesicles released by different strains of Acanthamoeba

Costa

Chagas

Menezes-Neto

et al. 2021

Cell Biology International

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Free living amoeba of the genus Acanthamoeba are opportunist protozoan involved in corneal, systemic, and encephalic infections in humans. Most of the mechanisms underlying intraspecies variations and pathogenicity are still unknown. Recently, the release of extracellular vesicles (EVs) by Acanthamoeba was reported. However, comparative characterization of EVs from distinct strains is not available. The aim of this study was to evaluate EVs produced by Acanthamoeba from different genotypes, comparing their proteases profile and immunomodulatory properties. EVs from four environmental or clinical strains (genotypes T1, T2, T4, and T11) were obtained by ultracentrifugation, quantitated by nanoparticle tracking analysis and analyzed by scanning and transmission electron microscopy. Proteases profile was determined by zymography and functional properties of EVs (measure of nitrite and cytokine production) were determined after peritoneal macrophage stimulation. Despite their genotype, all strains released EVs and no differences in size and/or concentration were detected. EVs exhibited a predominant activity of serine proteases (pH 7.4 and 3.5), with higher intensity in T4 and T1 strains. EVs from the environmental, nonpathogenic T11 strain exhibited a more proinflammatory profile, inducing higher levels of Nitrite, tumor necrosis factor alpha and interleukin‐6 via TLR4/TLR2 than those strains with pathogenic traits (T4, T1, and T2). Preincubation with EVs treated with protease inhibitors or heating drastically decreased nitrite concentration production in macrophages. Those data suggest that immunomodulatory effects of EVs may reflect their pathogenic potential depending on the Acanthamoeba strains and are dependent on protease integrity.

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“…T11 is considered the third most abundant genotype in AK (Maciver et al ., 2013), which suggests its pathogenic potential. Antigens from the strain R2P5 were also recognized by mAb3, an environmental isolate of T1 genotype (Possamai et al ., 2018). This genotype is rare, but it has been associated with cases of GAE, being the second in relevance in this disease (Alsam et al ., 2005; Sissons et al ., 2006; Maciver et al ., 2013).…”

Section: Discussionmentioning

confidence: 99%

Acanthamoeba spp. monoclonal antibody against a CPA2 transporter: a promising molecular tool for acanthamoebiasis diagnosis and encystment study

et al. 2020

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Free-living amoeba of the genus Acanthamoeba are ubiquitous protozoa involved in opportunistic and non-opportunistic infection in humans, such as granulomatous amoebic encephalitis and amoebic keratitis. Both infections have challenging characteristics such as the formation of the resistant cysts in infected tissues, hampering the treatment and most usual diagnosis depending on time-consuming and/or low sensitivity techniques. The use of monoclonal antibodies presents itself as an opportunity for the development of more effective alternative diagnostic methods, as well as an important and useful tool in the search for new therapeutic targets. This study investigated the possibility of using a previously produced monoclonal antibody (mAb3), as a diagnostic tool for the detection of Acanthamoeba trophozoites by direct and indirect flow cytometry and immunofluorescence. Immunoprecipitation assay and mass spectrometry allowed the isolation of the antibody's target and suggested it is a transporter part of the CPA (cation: proton antiporter) superfamily. In vitro tests indicate an important role of this target in Acanthamoeba's encystment physiology. Our results support the importance of studying the role of CPA2 transporters in the context of acanthamoebiasis, as this may be a way to identify new therapeutic candidates.

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Acanthamoeba of three morphological groups and distinct genotypes exhibit variable and weakly inter-related physiological properties

Cited by 18 publications

References 48 publications

Genotypic diversity of Acanthamoeba strains isolated from Chilean patients with Acanthamoeba keratitis

Genotypic diversity of Acanthamoeba strains isolated from Chilean patients with Acanthamoeba keratitis

Distinct immunomodulatory properties of extracellular vesicles released by different strains of Acanthamoeba

Acanthamoeba spp. monoclonal antibody against a CPA2 transporter: a promising molecular tool for acanthamoebiasis diagnosis and encystment study

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