Booton Gregory C, Rogerson Andrew, Bonilla Tonya D, Seal David V, Kelly Daryl J, Beattie Tara K, Tomlinson Alan, Lares-Villa Fernando, Fuerst Paul A, Byers Thomas J
Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA.
J Eukaryot Microbiol. 2004 Mar-Apr;51(2):192-200. doi: 10.1111/j.1550-7408.2004.tb00545.x.
Previous molecular examination of Acanthamoeba spp. has resulted in the determination of distinct genotypes in this genus (designated T1-T12, T14). Genotype T4 has been responsible for the majority of cases of Acanthamoeba keratitis. Here we examine the relative abundance of environmental T4 isolates on beaches and ask whether they have temperature and salinity tolerances that could enhance pathogenicity. Twenty-four Acanthamoeba strains were isolated from beach sand (n = 20), soil (n = 3), and tap water (n = 1) in south Florida. Phylogenetic analysis identified 19 of 24 isolates as T4, the Acanthamoeba keratitis-associated genotype. The remaining isolates were genotype T5 (4) and T11 (1). Nearly all beach isolates were genotype T4, whereas the tap water and soil isolates were mostly T5. All amoebae grew at 0, 1.0, and 2.0% salt and 19 of 20 beach isolates also grew at 3.2%. No soil or tap-water acanthamoebae reproduced at 3.2%. All isolates grew at 37 degrees C and two (T5) at 42 degrees C. Little correlation existed between beach location, salt-tolerance, and genetic relatedness. Overall, the large majority of environmental isolates obtained were genotype T4, suggesting it may be the most common genotype in this environment and could be a potential source of Acanthamoeba keratitis infections.
先前对棘阿米巴属的分子检测已确定了该属中的不同基因型（命名为T1 - T12、T14）。基因型T4导致了大多数棘阿米巴角膜炎病例。在此，我们研究了海滩上环境T4分离株的相对丰度，并询问它们是否具有可能增强致病性的温度和盐度耐受性。从佛罗里达州南部的海滩沙子（n = 20）、土壤（n = 3）和自来水（n = 1）中分离出24株棘阿米巴菌株。系统发育分析确定24株分离株中有19株为T4，即与棘阿米巴角膜炎相关的基因型。其余分离株为基因型T5（4株）和T11（1株）。几乎所有海滩分离株都是基因型T4，而自来水和土壤分离株大多是T5。所有变形虫在0%、1.0%和2.0%的盐浓度下都能生长，20株海滩分离株中有19株在3.2%的盐浓度下也能生长。没有土壤或自来水来源的棘阿米巴在3.2%盐浓度下繁殖。所有分离株在37℃下都能生长，有两株（T5）在42℃下能生长。海滩位置、耐盐性和遗传相关性之间几乎没有关联。总体而言，获得的绝大多数环境分离株是基因型T4，这表明它可能是该环境中最常见的基因型，并且可能是棘阿米巴角膜炎感染的潜在来源。
