摘要
目的探讨侵袭性真菌血流感染菌株分布及耐药情况,同时对热带念珠菌唑类耐药菌株进行流行病学分析,为临床抗真菌用药提供理论依据。方法收集中国科学技术大学附属第一医院临床血流感染患者分离的真菌菌株,采用基质辅助激光解吸电离飞行时间质谱技术的全自动快速微生物质谱检测系统(VITEK-MS)对菌种进行鉴定,同时用VITEK-2 AST-YS08试剂盒对菌株进行药敏试验。用PCR技术扩增热带念珠菌的6对管家基因并测序,测序结果与热带念珠菌多位点序列分型(MLST)数据库比对得到菌株的二倍体序列型别(diploid sequence type,DST),再利用goeBURST软件对结果进行亲缘性分析。结果2022年8月—2025年1月中国科学技术大学附属第一医院血培养阳性标本共分离47株真菌,排名前三位的分别是白念珠菌15株、热带念珠菌13株、近平滑念珠菌复合群11株。患者主要分布在重症监护病区(65.22%),其中重症医学科36.96%、心脏大血管外科重症监护室19.57%、神经重症监护室8.70%。真菌药物敏感性分析显示近平滑念珠菌和热带念珠菌对氟康唑不敏感率分别为22.22%和76.92%,但棘白菌素对大部分真菌有较低的MIC值。MLST型别分析显示13株热带念珠菌分属于9个DST,其中3个DST在该次研究中首次报道。菌株系统进化分析显示热带念珠菌唑类耐药菌株出现MLST型别聚集现象,对氟康唑和伏立康唑同时耐药的热带念珠菌都属于同一克隆簇。结论念珠菌是真菌血流感染最常见的病原体,白念珠菌对唑类抗真菌药耐药率低,近平滑念珠菌对唑类药物有一定的不敏感率,但热带念珠菌对唑类药物不敏感率较高,已不推荐唑类药物作为热带念珠菌感染一线用药。热带念珠菌唑类耐药菌株存在MLST型别聚集现象,应在临床工作中加强对热带念珠菌的流行病学研究。
Objective To investigate the pathogen distribution and antifungal susceptibility of the strains isolated from invasive fungal bloodstream infections,and conduct epidemiological analysis of Candida tropicalis for improving clinical antifungal treatment.Methods Fungal isolates from blood were collected at the clinical laboratories.Microbial identification and antifungal susceptibility testing were conducted by matrix assisted laser desorption ionization time of flight mass spectrometry(MALDI-TOF)and VITEK2 AST-YS08 kit,respectively.Genotyping of C.tropicalis were conducted using multilocus sequence typing(MLST)system to explore the molecular epidemiology.The MLST clonal clusters(CCs)were analyzed by goeBURST software.Results A total of 47 fungal strains isolated from 46 patients were collected from August 2022 to January 2025.The patients are mainly in intensive care units(65.22%),including 36.96%in internal medicine intensive care unit,19.57%in cardiac and vascular surgery intensive care unit,and 8.70%in neurological intensive care unit.The top three strains are C.albicans(n=15),C.tropicalis(n=13)and C.parapsilosis complex(n=11).Antifungal susceptibility testing showed that fluconazole-non-susceptible rate was 22.22%in C.parapsilosis and 76.92%in C.tropicalis.However,echinocandin drugs showed low minimum inhibitory concentration(MIC)against most fungal isolates.The concatenated sequences of the 13 strains of C.tropicalis were classified into 9 diploid sequence types(DSTs),3 of which were newly identified DSTs.Phylogenetic analysis found clonal aggregation between azole-resistant C.tropicalis isolates.The strains resistant to both fluconazole and voriconazole are classified into the same clone cluster.Conclusions Candida are still the most common pathogens causing fungal bloodstream infections.C.albicans showed low resistance to azole drugs.C.parapsilosis showed certain degree of azole-non-susceptibility.Significantly,C.tropicalis strains were highly resistant to azoles.Azole drugs are apparently not suitable for first-line treatment of C.tropicalis candidemia.The clonal aggregation phenomenon of azole-resistant isolates calls for more epidemiological researches on C.tropicalis in future clinical practice.
作者
王影
周馨
许良飞
金佩佩
WANG Ying;ZHOU Xin;XU Liangfei;JIN Peipei(Department of Laboratory Medicine,the First Affiliated Hospital of USTC,Division of Life Sciences and Medicine,University of Science and Technology of China,Hefei 230036,China)
出处
《中国感染与化疗杂志》
北大核心
2025年第6期619-625,共7页
Chinese Journal of Infection and Chemotherapy
基金
安徽省教育厅高校优秀青年项目(2022AH030126)
安徽省自然科学基金面上项目(2108085MH299)。
关键词
真菌血流感染
念珠菌
唑类耐药
多位点序列分型
fungal bloodstream infection
Candida
azole resistance
multilocus sequence typing
