真菌性角膜炎的病原学分析及鉴定

Identification of Fusarium solani as the prevalent strain in fungal keratitis

目的掌握真菌性角膜炎在吉林省的病原菌种类和流行病学特征，建立主要病原菌种的快速、特异性鉴定方法。方法采集225例疑似真菌性角膜炎患者的角膜刮片，分离、鉴定病原真菌，进行流行病学分析；建立主要病原菌种茄病镰刀菌的复合PER鉴定方法，用于角膜刮片的快速鉴定。结果225例患者中有156例确诊为真菌感染角膜炎，检出率为69．3％。其中12例患者为两种真菌共感染，共分离获得168株病原真菌。以镰刀菌属、曲霉属及假丝酵母属较多见，其中，主要病原菌种为茄病镰刀菌（34．5％）。建立的复合PcR方法可根据330bp特异性片段鉴定茄病镰刀菌，并可直接检测液体培养后的角膜刮片。结论真菌性角膜炎在吉林省的主要病原流行菌种为茄病镰刀菌。本文所建立的复合PCR方法适于角膜刮片标本的快速鉴定。

Objective To investigate the etiological and epidemiological characteristics of fungal keratitis in Jilin province of China and to establish a rapid and specific method for molecular identification of the prevalent fungal pathogens. Methods Corneal scrapings were collected from 225 patients with suspec- ted fungal keratitis. Fungal strains were isolated and identified based on their morphology and physiological characteristics. The epidemiological characteristics of all isolated strains causing fungal keratitis were statisti- cally analyzed. Species-specific primers of Fusarium solani （F. solani） were designed and used together with the universal fungal primers to establish a multiplex PCR assay for identification of F. solani in corneal scrapings. Results 156 out of 225 patients （69.3%） were diagnosed as fungal keratitis by fungal culture followed by the examination of morphological and physiological characteristics. A total of 168 pathogenic fun- gi strains were isolated, most of which were Fusarium spp. （ 49. 4% ）, followed by Aspergillus spp. （ 17.9% ） and Candida spp. （ 14.3% ）. F. solani was the predominant pathogen accounting for 34.5% in all patients. Most of the patients （87.5%） were farmer and male patients （57.1%） accounted for the ma- jority of 156 patients as well. Corneal trauma （38.5%） was considered as the main predisposing factor. The established multiplex PCR could specifically amplify a 300 bp nucleotide fragment of F. solani. It could be used for a rapid identification of F. solani in corneal scrapings. Conclusion Fusarium genus, particularly the species of F. solani, was the predominant pathogen for fungal keratitis in Jilin province of China. Corne- al trauma was the most important predisposing factor. The established multiplex PCR could identify fungal in- fection from corneal scrapings rapidly and specifically. These findings are very important for the early diagno- sis and treatment of fungal keratitis.