Antifungal susceptibility and distribution of Candida spp. isolates from the University Hospital in the municipality of Dourados, State of Mato Grosso do Sul, Brazil

Introduction Hospital infections caused by Candida spp. are a leading cause of morbidity and mortality in hospitalized patients, particularly those that are critically ill or immunocompromised. In this study, the distribution of Candida species in isolates from the University Hospital of the Federal University at Grande Dourados and their in vitro susceptibility to antifungal drugs were analyzed. Methods Yeasts were phenotypically identified using classical methodologies. Antifungal susceptibility tests to amphotericin B and fluconazole were performed using the broth microdilution technique. Results A total of 50 Candida isolates were obtained from hospitalized patients during the study period. We analyzed yeast isolates from urine (n=31; 62%), blood (n=12; 24%), and tracheal secretions (n=7; 14%). The following Candida species were identified: C. tropicalis (n=21; 42%), C. albicans (n=18; 36%), C. glabrata (n=10; 20%), and C. krusei (n=1; 2%). Antifungal susceptibility tests demonstrated that C. albicans was susceptible to both antifungal agents. However, 31.2% of the non-C. albicans Candida isolates displayed dose-dependent susceptibility to fluconazole, and 3.1% were resistant to amphotericin B. Conclusions In contrast to previous reports, our results indicated that C. tropicalis was the most commonly isolated yeast species among the hospital patients. The predominance of non-C. albicans Candida infections confirms the importance of species-level identification for implementing appropriate antifungal therapies.

引言 假丝酵母菌属（Candida spp.）引发的医院感染是住院患者，尤其是重症或免疫功能低下人群发病与死亡的首要诱因之一。本研究针对大杜拉多斯联邦大学附属医院分离的假丝酵母菌菌种分布情况，及其对抗真菌药物的体外药敏性展开分析。
研究方法 采用经典表型鉴定方法对酵母菌株进行分型。针对两性霉素B与氟康唑的药敏试验，采用肉汤微量稀释法完成。
结果 本研究周期内共从住院患者体内分离得到50株假丝酵母菌。所分析的酵母分离株来源分别为尿液（n=31，占比62%）、血液（n=12，占比24%）与气管分泌物（n=7，占比14%）。经鉴定，本次分离的假丝酵母菌菌种包括：热带假丝酵母菌（C. tropicalis，n=21，占比42%）、白假丝酵母菌（C. albicans，n=18，占比36%）、光滑假丝酵母菌（C. glabrata，n=10，占比20%）以及克柔假丝酵母菌（C. krusei，n=1，占比2%）。药敏试验结果显示，白假丝酵母菌对两种受试抗真菌药物均敏感。但31.2%的非白假丝酵母菌分离株对氟康唑呈现剂量依赖性敏感，另有3.1%的菌株对两性霉素B耐药。
结论 与既往研究报道不同，本研究结果显示热带假丝酵母菌是本次住院患者分离株中最常见的酵母菌种。非白假丝酵母菌感染占主导地位的现状，证实了菌种水平鉴定对制定合理抗真菌治疗方案的重要性。