角膜炎棘阿米巴的18S核糖体DNA基因型鉴定

Molecular characteristics of Acanthamoeba strains from keratitis patients

目的 鉴定角膜炎棘阿米巴分离株的 18S核糖体DNA(18SrDNA ,Rns)基因型。方法分离转种培养 2 6株致角膜炎的棘阿米巴虫株 ,提取虫株全基因组DNA ,应用棘阿米巴属特异性引物 ,通过聚合酶链反应 (PCR)扩增部分 18SrDNA序列。扩增产物测序后 ,采用分子生物学软件ClustalX和MEGA2对所测序列进行分析 ,与基因库中已有序列进行比较 ,分析北京市眼科研究所保存的棘阿米巴虫株Rns基因型特点及与其他国家和地区虫株的基因型异同。结果 分离保存的 2 6株感染角膜的棘阿米巴虫株中 ,2 5株 (96 % )属于RnsT4基因型 ,1株 (4% )属于RnsT3基因型。结论根据Rns基因特点 ,感染角膜的棘阿米巴虫株多属于T4基因型 ,部分虫株属于T3基因型 ,此分型结果与国外的相似 ,感染角膜的棘阿米巴可能与特定的基因型有关。

Objective To study the molecular characteristics of Acanthamoeba strains isolated from keratitis patients. Methods Twenty six Acanthamoeba strains were isolated from corneal ulcers between 1994 and 2002. Partial genome DNA sequences of all strains of Acanthamoeba were amplified using PCR and then the PCR products were sequenced. The partial DNA sequences were analyzed by software Clustal X and MEGA2. The results of Acanthamoeba obtained from Beijing Tongren Hospital were compared with strains from other countries and districts. Results Of 26 Acanthamoeba strains isolated from the patients, 25 (96%) were 18S rDNA ( Rns ) genotype T4 and one (4%) was T3. These results were similar to those obtained from other countries and districts. Conclusions According to the Rns genotype classification criterion, most of Acanthamoeba strains isolated from keratitis patients in Beijing are genotype T4 and only few of these strains are genotype T3. The Acanthamoeba infecting the cornea might belong to the specific 18S rDNA genotype.