Molecular Methods for the Diagnosis of Fungal Infections
Invasive mycoses are major causes of infectious morbidity and mortality, particularly in immuno-compromised or debilitated hosts. The rapid progression of disease in such susceptible populations makes an early and accurate diagnosis essential for optimum patient management and therapy. This chapter reviews methods for the extraction, purification, amplification and detection of fungal nucleic acids from clinical materials. Purification of fungal nucleic acids prior to polymerase chain reaction (PCR) amplification has traditionally been accomplished using phenol–chloroform extraction and alcohol precipitation. The availability of manual commercial deoxyribonucleic acid extraction kits has made the isolation and purification of fungal nucleic acids more straightforward. The true value of any diagnostic test is its ability to positively influence patient management or clinical outcome. The increased sensitivity of PCR tests compared to antigen or antibody detection tests holds promise for an earlier diagnosis of invasive fungal diseases, before the appearance of clinical or radiological signs.