McMullan R, Metwally L, Coyle P V, Hedderwick S, McCloskey B, O'Neill H J, Patterson C C, Thompson G, Webb C H, Hay R J
Department of Medical Microbiology, The Royal Hospitals, Belfast, Northern Ireland.
Clin Infect Dis. 2008 Mar 15;46(6):890-6. doi: 10.1086/528690.
Invasive Candida infection among nonneutropenic, critically ill adults is a clinical problem that has received increasing attention in recent years. Poor performance of extant diagnostic modalities has promoted risk-based, preemptive prescribing in view of the poor outcomes associated with inadequate or delayed antifungal therapy; this risks unnecessary overtreatment. A rapid, reliable diagnostic test could have a substantial impact on therapeutic practice in this patient population.
Three TaqMan-based real-time polymerase chain reaction assays were developed that are capable of detecting the main medically important Candida species, categorized according to the likelihood of fluconazole susceptibility. Assay 1 detected Candida albicans, Candida parapsilosis, Candida tropicalis, and Candida dubliniensis. Assays 2 and 3 detected Candida glabrata and Candida krusei, respectively. The clinical performance of these assays, applied to serum, was evaluated in a prospective trial of nonneutropenic adults in a single intensive care unit.
In all, 527 specimens were obtained from 157 participants. All 3 assays were run in parallel for each specimen; they could be completed within 1 working day. Of these, 23 specimens were obtained from 23 participants categorized as having proven Candida infection at the time of sampling. If a single episode of Candida famata candidemia was excluded, the estimated clinical sensitivity, specificity, and positive and negative predictive values of the assays in this trial were 90.9%, 100%, 100% and 99.8%, respectively.
These data suggest that the described assays perform well in this population for enhancing the diagnosis of candidemia. The extent to which they may affect clinical outcomes, prescribing practice, and cost-effectiveness of care remains to be ascertained.
非中性粒细胞减少的重症成年患者侵袭性念珠菌感染是近年来日益受到关注的临床问题。鉴于抗真菌治疗不足或延迟会导致不良后果，现有诊断方法效果不佳促使基于风险的先发制性用药；这存在不必要过度治疗的风险。一种快速、可靠的诊断测试可能会对该患者群体的治疗实践产生重大影响。
开发了三种基于TaqMan的实时聚合酶链反应检测方法，能够检测主要的医学上重要的念珠菌物种，并根据氟康唑敏感性的可能性进行分类。检测方法1检测白色念珠菌、近平滑念珠菌、热带念珠菌和都柏林念珠菌。检测方法2和3分别检测光滑念珠菌和克柔念珠菌。在一个重症监护病房对非中性粒细胞减少的成年人进行的前瞻性试验中，评估了这些应用于血清的检测方法的临床性能。
总共从157名参与者中获取了527份标本。每个标本同时进行所有三种检测；它们可在1个工作日内完成。其中，从23名在采样时被分类为已证实念珠菌感染的参与者中获取了23份标本。如果排除一起法塔念珠菌血症病例，该试验中检测方法的估计临床敏感性、特异性、阳性和阴性预测值分别为90.9%、100%、100%和99.8%。
这些数据表明，所描述的检测方法在该人群中对增强念珠菌血症的诊断表现良好。它们可能影响临床结局、处方实践和护理成本效益的程度仍有待确定。
