互隔交链孢霉菌性角膜炎的临床与病原学研究

The clinical and pathogenic characteristics of keratitis caused by Alternaria alternata

目的探讨互隔交链孢霉菌性角膜溃疡的临床和实验室特征。方法对真菌性角膜溃疡患者，裂隙灯显微镜下观察临床表现后，角膜刮片作10％KOH湿片、Giemsa染色显微镜检查，真菌菌丝阳性者作真菌培养鉴定，并根据美国国家临床实验室标准化委员会（NCCLS）M38-A方案进行体外药敏试验，同时对患者给予两性霉素B、酮康唑、氟康唑滴眼液治疗，并观察抗真菌药物的疗效。以分离的互隔交链孢霉菌株制作兔真菌性角膜溃疡模型，5d和14d后处死兔，取角膜行真菌培养和组织学检查。结果互隔交链孢霉菌性角膜炎患者均为单眼患病，患者和兔模型的角膜溃疡灶均较浅薄，呈淡灰色，边界模糊。显微镜下角膜刮片可见直且粗大的无色隔膜菌丝，并有大量球形厚垣孢子位于菌丝顶端或相连。分离培养基中该种真菌菌丝为棕色，壁砖墙分隔的深棕色孢子链生于棕色分生孢子梗顶端。体外药物敏感试验显示该种真菌对两性霉素B、酮康唑、氟康唑、伏立康唑、咪康唑、益康唑和特比萘芬敏感，对克霉唑、氟胞嘧啶及伊曲康唑耐药。23例患者除1例手术治愈外，其余22例用两性霉素B、酮康唑、氟康唑联合频繁滴眼治愈，平均治愈时间34d。结论互隔交链孢霉菌性角膜溃疡具有独特的临床和实验室特征，对角膜毒力较低，抗真菌药物联合滴眼可完全治愈。

Objective To study the clinical and pathogenic characteristics of keratitis caused by Alternaria ahernata and to provide evidence for the diagnose and treatment of mycotic keratitis. Methods The patients with keratitis were examined by lamp microscope; the direct smears of corneal scrapings were stained using 10% potassium hydroxide and Giemsa＇ s staining and the results were observed under microscope. After hypha was found, the samples from corneal were taken for fungal culture and fungal susceptibility test in vitro according to the National Community of Clinical Laboratory Standard （NCCLS） document M38-A at the same time. Ketroconazole, Amphotericin B and Fluconazole eye drops were applied into eyes frequently and alternately. The affectivity of the treatment were also observed. The isolates of A/ternar/a a/ternata from patients were used to induce keratitis in rabbits. The rabbits were sacrificed by air after 5 days and 14 days and their corneas were taken for pathology and inoculating for fungi. Results All the patients have only one eye with Alternaria alternata＇s keratitis and their average age was 50 years old. The lesions of corneal necrosis in the patients and Alternaria alternata＇s keratitis in the rabbits were appeared as light grey, shallow and a diffused edge. Alternaria alternata showed as thick transparent hypha and a great of spherica chlamydospores on the top of hypha or cluster one and the other in corneal scraping under microscope. The hypha and spores of Alternaria alternata in the culture medium were all brown and the spores were separated into cells like wall brick and grew on the top of spores linking like chains. Antimicrobial susceptibility testing in vitro showed that Alternaria alternata was susceptible to Voriconazole, Amphotericin B, Ketoconazole, Miconazole, Econazole, Terbinafine and Fluconazole but it was resistant to Clotrimazole, Flucytosine ang Itraconazole. 22 of the patients were cured by dropping Amphotericin B, Ketoconazole and Fluconazole frequently and alternately but surgery was performed in one case. The mean cured time was 34 day. The lesion of rabbits keratitis caused by Alternaria alternata was thin and localized only in the region of lacking epicytes. The isolate from the rabbit＇s keratitis model was Alternaria alternata. Conclusions The keratitis caused by Alternaria alternata has its distinct clinical and laboratory characteristics. The virulence of Alternaria alternata is relatively low to cornea and the combination of antifunsal agents could cure Alternaria alternatal keratitis.