Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, 1 You Yi Road, Yuzhong District, Chongqing, 400016, China.
Department of Clinical Laboratory, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 611731, China.
BMC Infect Dis. 2021 Sep 29;21(1):1020. doi: 10.1186/s12879-021-06678-4.
Cryptococcosis is a major opportunistic invasive mycosis in immunocompromised patients, but it is also increasingly seen in immunocompetent patients. In the early stages of cryptococcosis, limitations of the detection method may hinder the diagnosis. A molecular diagnostic technique based on nucleic acid sequence-based amplification (NASBA) method was developed to fulfil the need for efficient diagnosis of cryptococcosis.
We compared the diagnostic performance of NASBA, PCR and cryptococcal antigen (CrAg) test (colloidal gold method) in clinical samples from 25 cryptococcosis patients (including 8 cryptococcal meningoencephalitis and 17 pulmonary cryptococcosis) who were categorized as proven cases (n = 10) and probable cases (n = 15) according to the revised EORTC/MSG definitions. 10 patients with non-Cryptococcus infection and 30 healthy individuals were categorized as control group.
The lowest detection limit of NASBA was 10 CFU/mL, and RNA of non-target bacteria or fungi was not amplified. The sensitivity of NASBA, PCR and colloidal gold method was 92.00% (95% CI 72.50-98.60%), 64.00% (95% CI 42.62-81.29%), 100.00% (95% CI 83.42-100.00%), and the specificity was 95.00% (95% CI 81.79-99.13%), 80.00% (95% CI 63.86-90.39%) and 82.50% (95% CI 66.64-92.11%) respectively. The highest specificity (97.50%), accuracy (95.38%) and k value (0.90) were achieved when both NASBA and colloidal gold results were positive.
NASBA is a new alternative detection method for cryptococcosis which is both accurate and rapid without expensive equipment and specialised personnel. It may be used as a tool for confirming current infection as well as monitoring the effectiveness of antifungal treatment. The use of NASBA to detect Cryptococcus RNA in blood samples is of great significance for the diagnosis of pulmonary cryptococcosis. The combination of NASBA and colloidal gold can improve the diagnostic accuracy of cryptococcosis.
cryptococcosis 是一种主要的机会性侵袭性真菌感染，发生于免疫功能低下的患者，但在免疫功能正常的患者中也越来越常见。在 cryptococcosis 的早期阶段，检测方法的局限性可能会阻碍诊断。基于核酸序列扩增（NASBA）方法的分子诊断技术应运而生，以满足高效诊断 cryptococcosis 的需求。
我们比较了 NASBA、PCR 和 cryptococcal 抗原（胶体金法）在 25 例 cryptococcosis 患者（包括 8 例 cryptococcal 脑膜脑炎和 17 例肺部 cryptococcosis）的临床样本中的诊断性能，这些患者根据修订后的 EORTC/MSG 定义分为确诊病例（n=10）和疑似病例（n=15）。10 例非 cryptococcus 感染患者和 30 例健康个体被归类为对照组。
NASBA 的最低检测限为 10 CFU/mL，非靶细菌或真菌的 RNA 未被扩增。NASBA、PCR 和胶体金法的灵敏度分别为 92.00%（95%CI 72.50-98.60%）、64.00%（95%CI 42.62-81.29%）、100.00%（95%CI 83.42-100.00%），特异性分别为 95.00%（95%CI 81.79-99.13%）、80.00%（95%CI 63.86-90.39%）和 82.50%（95%CI 66.64-92.11%）。当 NASBA 和胶体金结果均为阳性时，特异性（97.50%）、准确性（95.38%）和 k 值（0.90）最高。
NASBA 是一种新的 cryptococcosis 检测方法，准确且快速，无需昂贵的设备和专业人员。它可以作为一种工具，用于确认当前感染以及监测抗真菌治疗的效果。在血液样本中使用 NASBA 检测 cryptococcus RNA 对肺部 cryptococcosis 的诊断具有重要意义。NASBA 与胶体金联合应用可提高 cryptococcosis 的诊断准确性。
