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

Abstract

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.

Investigating Domestic Shower Settings as a Risk Factor for Acanthamoeba Keratitis

“…Similar to other environmental studies where the genotype T4 of Acanthamoeba spp. was reported as the predominant genotype [44][45][46], the current study found that 3/4 (75%) of sequenced strains were T4 genotype irrespective of the sample site in bathrooms. Additionally, one isolate from the shower curtain/door was identified as A. castellanii T3.…”

Curcuma longa rhizome extract and Curcumin reduce the adhesion of Acanthamoeba triangularis trophozoites and cysts in polystyrene plastic surface and contact lens

“…Acanthamoeba triangularis ( A. triangularis ) is a free-living protozoan ubiquitously found in nature, such as water and soil. The parasite is a causative agent of several diseases, including granulomatous amoebic encephalitis ( Kalra et al, 2020 ) and Acanthamoeba keratitis ( Jercic et al, 2019 ). In keratitis disease, severe vision loss and complete blindness caused by parasites are the main case in contact lens users ( Lee et al, 2017 ).…”

Free-living amoebae and their relationship to air quality in hospital environments: characterization of Acanthamoeba spp. obtained from air-conditioning systems

“…refrigeration systems following a legionellosis outbreak in and around a hospital reported the presence of nine Acanthamoeba isolates belonging to the T4 genotype, which had amoeba resistant bacteria in its interior, emphasizing the importance of these amoebas as bacterial vehicles (Scheikl et al, 2016). All genotypes identified in our study are associated with cases of human infections (Siddiqui and Khan, 2012;Jercic et al, 2019). These results deserve special attention from the hospital community, considering the isolation environment, the characteristic of many patients in a hospital environment, as they may be immunologically susceptible to infections, as well as the opportunistic nature of Acanthamoeba spp.…”

“…Some studies relate the T11 genotype to cases of amoebic keratitis (Hajialilo et al ., 2016; Jercic et al ., 2019). This was one of the genotypes described as causing this infection in a large research carried out in Austria that included cases of Acanthamoeba infections in the last 20 years (Walochnik et al ., 2015).…”

“…All genotypes identified in our study are associated with cases of human infections (Siddiqui and Khan, 2012; Jercic et al ., 2019). These results deserve special attention from the hospital community, considering the isolation environment, the characteristic of many patients in a hospital environment, as they may be immunologically susceptible to infections, as well as the opportunistic nature of Acanthamoeba spp.…”