Division of Neurology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
Front Cell Infect Microbiol. 2022 Jul 13;12:931546. doi: 10.3389/fcimb.2022.931546. eCollection 2022.
Primary amebic meningoencephalitis (PAM) is a rare and fatal central nervous system infection caused by , a free-living amoeba found in the environment. To date, eight pathogenic genotypes have been reported worldwide. We aimed to explore the genotypes of that cause primary amebic meningoencephalitis in Thailand. In 2021, the 17th PAM case was reported, and a retrospective literature search of PAM cases in Thailand from 1982 through April 2021 was performed. Phylogenetic and genotyping analyses of the two mitochondrial (12S rRNA and 16S rRNA) and nuclear (ITS1 and 5.8s rRNA) genes of were performed on four available clinical isolates. Based on the mitochondrial and nuclear genes, genotype T3 was found to cause PAM in three out of four cases. However, disagreement between the genotype based on the mitochondrial and nuclear genes was found in one of the PAM cases, in which the 12S rRNA locus suggested the causative genotype as T1, while the ITS1 implied genotype T4. The discrepancy between the mitochondrial and nuclear genome was previously observed, which suggests the possible horizontal gene transfer among species. Based on the ITS1 gene, two genotypes, T3 and T4, were found to be the genotypes causing PAM in this study. In addition, genotype T2 was previously reported in a traveler who was infected in Thailand. Thus, at least three genotypes (T2, T3, and T4) of are found to be associated with PAM in Thailand.
原发性阿米巴脑膜脑炎（PAM）是一种罕见且致命的中枢神经系统感染，由自由生活的阿米巴原虫引起，这种阿米巴原虫存在于环境中。迄今为止，全球已报告了 8 种致病基因型。我们旨在探索导致泰国原发性阿米巴脑膜脑炎的 基因型。2021 年报告了第 17 例 PAM 病例，并对 1982 年至 2021 年 4 月期间泰国 PAM 病例的回顾性文献进行了检索。对 4 个临床分离株的两个线粒体（12S rRNA 和 16S rRNA）和核（ITS1 和 5.8s rRNA）基因进行了遗传进化和基因分型分析。基于线粒体和核基因，发现 T3 基因型导致了 4 例中的 3 例 PAM。然而，在 1 例 PAM 病例中发现了线粒体和核基因之间的基因型不一致，其中 12S rRNA 基因座提示致病基因型为 T1，而 ITS1 则提示基因型为 T4。先前观察到线粒体和核基因组之间的差异，这表明 种间可能存在水平基因转移。基于 ITS1 基因，发现两种 基因型，T3 和 T4，是本研究中导致 PAM 的基因型。此外，先前在一名在泰国感染的旅行者中报告了基因型 T2。因此，至少有三种 基因型（T2、T3 和 T4）与泰国的 PAM 相关。
