常見的院內黴菌感染──侵襲性麴菌感染的診斷

Diagnosis of Invasive Aspergillus Infection - A Common Infection in Hospitals

麴菌普遍存在於環境中，但侵襲性麴菌感染通常只發生於免疫功能不全的病人，而且這個問題近來越來越棘手，主要原因為目前癌症病人接受化學治療和免疫療法的人數持續增加，這群病人因長期免疫低下更容易受到感染。臨床診斷麴菌感染非常困難，組織切片和黴菌培養是目前的診斷的標準，然而培養法敏感性不足，並且無法區分是麴菌移生或感染。切片檢查又常受限於病人因容易出血而無法施行。其他的檢驗方法，例如半乳甘露聚醣檢驗、連鎖聚合酶反應、次世代總體基因體定序，近來於臨床的應用日益普及，這些檢驗方法合併電腦斷層影像檢查，再加上考量病人是否具有麴菌感染的危險因子，可以增加病人提早被診斷出侵襲性麴菌感染，並且增加及早使用抗黴菌藥物治療的機會。在本篇文章中，我們介紹目前臨床常用於侵襲性黴菌感染的診斷工具，和討論這些診斷的敏感性和專一性。

Aspergillus species are universally present in the environment. Invasive Aspergillus infections usually occur in immunocompromised patients. It has become a serious problem largely due to the growing number of cancer patients who receive chemotherapy or immunotherapy, which prolongs the duration of immunocompromise. Diagnosis is the most challenging aspect of dealing with Aspergillus infections. Histology and culture remain the diagnostic gold standards. However, culture is not sensitive and cannot distinguish between colonization and true infections, and an invasive biopsy is usually contraindicated in patients with a bleeding tendency. Other diagnostic methods, such as the galactomannan test, polymerase chain reaction (PCR)-based studies, and metagenomic next-generation sequencing, have been used in clinical settings. These laboratory tests combined with computed tomography and the evaluation of clinical risk factors would promote the early diagnosis and initiation of early antifungal therapy. In this review, we introduce the clinical implications, sensitivity, and specificity of these tests in diagnosing invasive Aspergillus infection.