Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
Med Mycol. 2020 Jan 1;58(1):83-92. doi: 10.1093/mmy/myz027.
We aim to assess intra- and interspecies differences in the virulence of Candida spp. strains causing candidemia using the invertebrate Galleria mellonella model. We studied 739 Candida spp. isolates (C. albicans [n = 373], C. parapsilosis [n = 203], C. glabrata [n = 92], C. tropicalis [n = 53], and C. krusei [n = 18]) collected from patients with candidemia admitted to Gregorio Marañon Hospital (Madrid, Spain). Species-specific infecting inocula (yeast cells/larva) were adjusted (5 × 105 [C. albicans, and C. tropicalis], 2 × 106-5 × 106 [C. parapsilosis, C. glabrata, and C. krusei]) and used to infect 10 larvae per isolate; percentage of survival and median survival per isolate were calculated. According to the interquartile range of the median survival, isolates with a median survival under P25 were classified as of high-virulence and isolates with a median survival over P75 as of low virulence. The median survival of larvae infected with different species was variable: C. albicans (n = 2 days, IQR <1-3 days), C. tropicalis (n = 2 days, IQR 1.5-4 days), C. parapsilosis (n = 2 days, IQR 2-3.5 days), C. glabrata (n = 3 days, IQR 2-3 days), and C. krusei (n = 7 days, 6.5->8 days) (P < .001). Differences in virulence among species were validated by histological examination (day +1 post-infection) in the larvae infected by the isolates of each virulence category and species. Virulence-related gene expression in C. albicans isolates did not reach statistical significance. We report species-specific virulence patterns of Candida spp. and show that isolates within a given species have different degrees of virulence in the animal model.
我们旨在使用无脊椎动物家蚕模型评估引起念珠菌血症的念珠菌属菌株的种内和种间毒力差异。我们研究了从马德里 Gregorio Marañon 医院（西班牙马德里）入院的念珠菌血症患者中分离出的 739 株念珠菌属菌株（白色念珠菌[n = 373]，近平滑念珠菌[n = 203]，光滑念珠菌[n = 92]，热带念珠菌[n = 53]和克柔念珠菌[n = 18]）。调整了特定种属的感染接种物（酵母细胞/幼虫）（5 × 105 [白色念珠菌和热带念珠菌]，2 × 106-5 × 106 [近平滑念珠菌，光滑念珠菌和克柔念珠菌]），并用于感染每株分离株的 10 只幼虫；计算了每株分离株的存活率和中位生存时间。根据中位生存时间的四分位距，将中位生存时间低于 P25 的分离株分为高毒力组，而中位生存时间高于 P75 的分离株分为低毒力组。不同种属感染的幼虫中位生存时间不同：白色念珠菌（n = 2 天，IQR <1-3 天），热带念珠菌（n = 2 天，IQR 1.5-4 天），近平滑念珠菌（n = 2 天，IQR 2-3.5 天），光滑念珠菌（n = 3 天，IQR 2-3 天）和克柔念珠菌（n = 7 天，6.5->8 天）（P <.001）。通过感染每种毒力类别的和种属的分离株后的幼虫在感染后第 1 天（+1 天）的组织学检查验证了种间毒力差异。白色念珠菌分离株的毒力相关基因表达未达到统计学意义。我们报告了念珠菌属的种特异性毒力模式，并表明在动物模型中，同种内的分离株具有不同程度的毒力。
