Laboratory Diagnosis of Mucormycosis: Current Status and Future Perspectives

Michaela Lackner; Rita Caramalho; Cornelia Lass-Flörl

Disclosures

Future Microbiol. 2014;9(5):683-695. 

In This Article

Abstract and Introduction

Abstract

Fungal infections caused by members of the Mucorales order are rapidly progressing and fatal. The importance of mucormycosis has grown in recent years as the number of patients with predisposing factors has increased dramatically. Clinical symptoms are elusive and conventional techniques are often insensitive and unspecific; in particular, cultures are often negative even though direct microscopy is positive. For early diagnosis of the causative agent of disease and subsequently guiding therapy to improving patients' outcome, molecular assays are promising add-ons. This article provides an overview on current laboratory methods for diagnosing mucormycosis with a special focus on new molecular-based tools. We aim to highlight the pros and cons of various techniques at hand. Given the increase in number and the severity of these infections, molecular approaches for improved diagnosis are highly warranted.

Introduction

Mucormycosis are life-threatening infections, caused by nonseptate or sparsely septate fungi that are affiliated to the order Mucorales.[1] Zygomycosis, the term used previously, has become less accurate based on a recent taxonomic reclassification that abolished Zygomycetes as a class.[2] Mucormycetes are considered as important animal and human pathogens. Among the most common genera are Apophysomyces, Cunninghamella, Lichtheimia, Mucor, Rhizomucor, Rhizopus and Saksenaea. Rhizopus is taking the lead, followed by Lichtheimia and Mucor, depending on the patient group affected and local epidemiology.[1] The aggressive nature of these infections means that delayed diagnosis and inadequate treatment highly impacts on mortality rates. Compared with early treatment, deferred therapy resulted in a twofold increase in mortality after 12 weeks (82.9 vs 48.9%).[3]

The overall prognosis of the infection depends on several factors, including the rapidness of diagnosis and treatment, the site of infection, underlying conditions and the immune status of the patient.[4] The economic impact of this devastating disease in Europe is estimated at approximately 50 million Euros/year.[5] The objective of this review is to provide a comprehensive overview on current developments in laboratory diagnostics of mucormycetes and to highlight pros and cons of conventional techniques and new approaches.

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