北部某區域級教學醫院致病酵母菌與藥物感受性分析

The Distribution of Species and Drug Susceptibilities of Pathogenic Yeasts Isolated from Patients in a Regional Teaching Hospital in Northern Taiwan

近十年來，台灣黴菌抗藥性監測計畫發現，臨床分離之Candida tropicalis（熱帶念珠菌）與環境中對fluconazole（氟康唑）具抗藥性的菌株親緣關係密切，皆屬於clade 4基因分群。類似現象亦在其他熱帶與亞熱帶地區（如中國、澳大利亞、泰國及新加坡）被陸續報導，顯示此基因分群已具區域性流行潛勢。
為了解區域級教學醫院酵母菌感染的現況，本研究分析自114位病人臨床檢體中分離的121株酵母菌。最常見菌種為Candida albicans（白色念珠菌，57.9%），其次為Nakaseomyces glabratus（光滑念珠菌，15.7%）、C.tropicalis（9.9%）、Candida parapsilosis（近平滑念珠菌，8.3%）、Cryptococcus neoformans（新型隱球菌，3.3%）及其他菌種（4.9%）。檢體來源以尿液（54.5%）為主，其次為血液（20.7%）與痰液（19%）。其中7件檢體為混合菌感染，以C.albicans / C. parapsilosis組合最常見。
藥物感受性試驗結果顯示，amphotericin B（兩性黴素B）與anidulafungin（助黴飛）對多數菌株具良好活性。Azoles（唑類）對C. albicans及C. parapsilosis的感受性均為100%，但12株C. tropicalis中有3株（25%）對fluconazole具抗藥性，其中2株對voriconazole（伏立康唑）亦具交叉抗藥性。多位點序列分型顯示，3株抗藥菌皆屬clade 4基因分群。
研究結果顯示，本院C. tropicalis感染排序為Candida第三名，其重要性不容小覷，fluconazole抗藥C. tropicalis皆為clade 4基因分群，amphotericinB與anidulafungin對多數菌株仍具良好感受性。建議醫療人員對於非白色念珠菌感染不可輕忽，要依臨床狀況與藥物感受性結果來治療念珠菌感染的病人。

A predominant fluconazole-resistant Candida tropicalis with clade 4 genotype causing candidemia in humans, has been found in both clinical and agriculture contexts. It has not only been found in Taiwan, but in other tropical/subtropical areas including China, Australia, Thailand, and Singapore. In the present study, we randomly analyzed 121 yeast samples isolated from 114 patients in a regional hospital. The most common pathogenic species was Candida albicans (57.9%), followed by Nakaseomyces glabratus (Candida glabrata) (15.7%), C. tropicalis (9.9%), Candida parapsilosis (8.3%), Cryptococcus neoformans (3.3%), and others (4.9%). The common sources were urine (54.5%), followed by blood (20.7%), sputum (19%), pus (3.3%), and cerebrospinal fluid (CSF) (2.5%). Seven specimens were found to harbor more than one species: five were a combination of C. albicans and N. glabratus, and one was C. albicans and C. parapsilosis, and the other was C. albicans and C. tropicalis. Approximately 25% (3/12) of C. tropicalis were resistant to fluconazole and all belonged to the clade 4 genotype. Two were cross-resistant to voriconazole. Our findings demonstrate that C. tropicalis fluconazole-resistant with clade 4 genotype exists in Taiwan. Non-albicans Candida infections should be handled with caution and treated appropriately based on clinical conditions and susceptibility reports.