DataSheet_1_Molecular Epidemiology, Antifungal Susceptibility, and Virulence Evaluation of Candida Isolates Causing Invasive Infection in a Tertiary Care Teaching Hospital.zip

BackgroundThe incidence of invasive candidiasis is increasing worldwide. However, the epidemiology, antifungal susceptibility, and virulence of Candida spp. in most hospitals remain unclear. This study aimed to evaluate invasive candidiasis in a tertiary care hospital in Nanchang City, China.
MethodsMALDI-TOF MS and 18S rDNA ITS sequencing were used to identify Candida strains. Randomly amplified polymorphic DNA analysis was used for molecular typing; biofilm production, caseinase, and hemolysin activities were used to evaluate virulence. The Sensititre™ YeastOne YO10 panel was used to examine antifungal susceptibility. Mutations in ERG11 and the hotspot regions of FKS1 of drug-resistant strains were sequenced to evaluate the possible mechanisms of antifungal resistance.
ResultsWe obtained 110 Candida strains, which included 40 Candida albicans (36.36%), 37 C. parapsilosis (33.64%), 21 C. tropicalis (19.09%), 9 C. glabrata (8.18%), 2 C. rugose (1.82%), and 1 C. haemulonii (0.91%) isolates. At a limiting point of 0.80, C. albicans isolates could be grouped into five clusters, C. parapsilosis and C. tropicalis isolates into seven clusters, and C. glabrata isolates into only one cluster comprising six strains by RAPD typing. Antifungal susceptibility testing revealed that the isolates showed the greatest overall resistance against fluconazole (6.36%), followed by voriconazole (4.55%). All C. albicans and C. parapsilosis isolates exhibited 100% susceptibility to echinocandins (i.e., anidulafungin, caspofungin, and micafungin), whereas one C. glabrata strain was resistant to echinocandins. The most common amino acid substitutions noted in our study was 132aa (Y132H, Y132F) in the azole-resistant strains. No missense mutation was identified in the hotpot regions of FKS1. Comparison of the selected virulence factors detectable in a laboratory environment, such as biofilm, caseinase, and hemolysin production, revealed that most Candida isolates were caseinase and hemolysin producers with a strong activity (Pz < 0.69). Furthermore, C. parapsilosis had greater total biofilm biomass (average Abs620 = 0.712) than C. albicans (average Abs620 = 0.214, p < 0.01) or C. tropicalis (average Abs620 = 0.450, p < 0.05), although all C. glabrata strains were either low- or no-biofilm producers. The virulence level of the isolates from different specimen sources or clusters showed no obvious correlation. Interesting, 75% of the C. albicans from cluster F demonstrated azole resistance, whereas two azole-resistant C. tropicalis strains belonged to the cluster Y.
ConclusionThis study provides vital information regarding the epidemiology, pathogenicity, and antifungal susceptibility of Candida spp. in patients admitted to Nanchang City Hospital.

背景：侵袭性念珠菌病（invasive candidiasis）的全球发病率呈上升趋势。然而，目前多数医院内念珠菌属（Candida spp.）的流行病学特征、抗真菌药物敏感性及毒力特征仍尚不明确。本研究旨在评估中国南昌市某三级医院收治患者的侵袭性念珠菌病相关情况。
方法：采用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）及18S rDNA内部转录间隔区（18S rDNA ITS）测序对念珠菌菌株进行鉴定；采用随机扩增多态性DNA（Randomly Amplified Polymorphic DNA, RAPD）分析开展分子分型；通过检测生物膜形成能力、酪蛋白酶活性及溶血素活性评估菌株毒力；使用Sensititre™ YeastOne YO10药敏板条进行抗真菌药物敏感性检测；对耐药菌株的ERG11基因及FKS1基因热点区域进行测序，以探究抗真菌耐药的潜在分子机制。
结果：本研究共收集到110株念珠菌菌株，涵盖40株白念珠菌（Candida albicans，占比36.36%）、37株近平滑念珠菌（C. parapsilosis，33.64%）、21株热带念珠菌（C. tropicalis，19.09%）、9株光滑念珠菌（C. glabrata，8.18%）、2株皱落念珠菌（C. rugose，1.82%）及1株海美木念珠菌（C. haemulonii，0.91%）。以0.80为界值，经RAPD分型后，白念珠菌可划分为5个聚类簇，近平滑念珠菌与热带念珠菌各分为7个聚类簇，而光滑念珠菌仅形成1个包含6株菌株的聚类簇。抗真菌药物敏感性检测结果显示，受试菌株对氟康唑的整体耐药率最高（6.36%），其次为伏立康唑（4.55%）。所有白念珠菌与近平滑念珠菌菌株对棘白菌素类药物（阿尼芬净、卡泊芬净及米卡芬净）均表现出100%敏感性，仅1株光滑念珠菌对棘白菌素类药物耐药。本研究中唑类耐药菌株最常见的氨基酸替换为132位氨基酸位点的Y132H、Y132F突变。未在FKS1基因的热点区域检测到错义突变。对实验室可检测的选定毒力因子（包括生物膜形成、酪蛋白酶及溶血素产生）进行比较分析后发现，多数念珠菌菌株可产生具有较强活性的酪蛋白酶与溶血素（Pz<0.69）。此外，近平滑念珠菌的总生物膜生物量（平均Abs620=0.712）显著高于白念珠菌（平均Abs620=0.214，p<0.01）与热带念珠菌（平均Abs620=0.450，p<0.05），但所有光滑念珠菌菌株均为低生物膜形成能力或无生物膜形成能力菌株。不同标本来源菌株及不同聚类簇菌株的毒力水平未表现出明显相关性。值得注意的是，聚类簇F中的75%白念珠菌表现出唑类耐药性，而2株唑类耐药的热带念珠菌均属于聚类簇Y。
结论：本研究为中国南昌市某三级医院收治患者的念珠菌属菌株的流行病学特征、致病性及抗真菌药物敏感性提供了关键参考数据。