A history of over 40 years of potentially pathogenic free-living amoeba studies in Brazil - a systematic review

Abstract

Free-living amoeba (FLA) group includes the potentially pathogenic genera Acanthamoeba, Naegleria, Balamuthia, Sappinia, and Vermamoeba, causative agents of human infections (encephalitis, keratitis, and disseminated diseases). In Brazil, the first report on pathogenic FLA was published in the 70s and showed meningoencephalitis caused by Naegleria spp. FLA studies are emerging, but no literature review is available to investigate this trend in Brazil critically. Thus, the present work aims to integrate and discuss these data. Scopus, PubMed, and Web of Science were searched, retrieving studies from 1974 to 2020. The screening process resulted in 178 papers, which were clustered into core and auxiliary classes and sorted into five categories: wet-bench studies, dry-bench studies, clinical reports, environmental identifications, and literature reviews. The papers dating from the last ten years account for 75% (134/178) of the total publications, indicating the FLA topic has gained Brazilian interest. Moreover, 81% (144/178) address Acanthamoeba-related matter, revealing this genus as the most prevalent in all categories. Brazil's Southeast, South, and Midwest geographic regions accounted for 96% (171/178) of the publications studied in the present work. To the best of our knowledge, this review is the pioneer in summarising the FLA research history in Brazil.

Prevalence of free-living amoebae in swimming pools and recreational waters, a systematic review and meta-analysis

“…Most isolates of Acanthamoeba spp. reported as pathogens are distributed among the T5, T11, T15, T3, and T4 genotypes, and among them, the T4 genotype is more prevalent in hot springs (Mahmoudi et al 2015 ; Fabros et al 2021 ) and is associated with most cases of Acanthamoeba keratitis (Diehl et al 2021 ; Bellini et al 2022 ). The presence and abundance of FLA in swimming pool water clearly indicate that in addition to these microorganisms being resistant to chlorine in the dosage used in the treatment of drinking water (Thomas et al 2004 ; Majid et al 2017 ; Gomes et al 2020 ), they are also resistant to chlorine and other disinfectants in the dosage used for swimming pools and artificial recreational waters (Rivera et al 1983 ; Kiss et al 2014 ; Zeybek et al 2017 ).…”

“…Free-living amoebae (FLA) are cosmopolitan and ubiquitous microorganisms widely distributed in the environment and can be opportunistic and/or pathogenic (Visvesvara et al 2007 ; Bellini et al 2022 ). They have been isolated from many natural and anthropogenic environmental matrices, including plants, soil, air conditioning dust, bottled mineral water, drinking water treatment and distribution system, and cooling towers (Landell et al 2013 ; Maschio et al 2015 ; Javanmard et al 2017 ; Soares et al 2017 ; Wopereis et al 2020 ; Pazoki et al 2020 ).…”