Fungal infections are life-threatening opportunistic infections that have emerged as a major cause of morbidity and mortality in critically ill patients. Yeast infections,mainly Candida spp., remain much more frequent than mold infections. Among mold infections, Aspergillus spp. represent the most frequently isolated filamentous fungi in these circumstances .Candida species are the most common cause of nosocomial fungal infections and the fourth most common source of hospital-acquired infections. Candidiasis is an infection caused by Candida, mostly limited to the skin, nails and mucous membranes. However, it can cause serious systemic infections. Candidiasis is an opportunistic infection occurring in presence of predisposing factors like extensive and prolonged administration of broad-spectrum antimicrobials, corticosteroids, immunosuppressive agents and cytotoxic drugs, diabetes mellitus, HIV, chronic renal failure, haemodialysis, renal transplantation or indwelling urinary catheter.The pathogenicity of Candida spp. is related to a combination of microbial factors such as their ability to grow at 37°C, polymorphism, biofilm formation, hydrolytic enzyme secretion, and phenotypic switching. Candida species are identified by different phenotypic methods including examination of their morphological features, analysis of their ability of carbohydrates assimilation and/or fermentation, and their ability of assimilating different nitrogen compounds. Numerous antifungal classes are used to treat Candida infections; polyenes, azoles, echinocandins and allylamines. These antifungals are used with varying efficacy depending on the type, site of infection and the susceptibility of different Candida species. Azoles are the most frequently used antifungal drugs to treat Candida infections as they achieve high success rates even over short durations of therapy. However, resistance among previously susceptible Candida species has emerged following the expanded use of antifungal agents. Antifungal susceptibility testing methods including broth dilution, disk diffusion and E test are now available with species-specific breakpoints developed by The Clinical and Laboratory Standards Institute (CLSI) for multiple antifungal agents.
The diagnosis of invasive fungal disease remains challenging in the clinical laboratory. The use of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of filamentous fungi as well as its application for antifungal resistance testing and strain typing Will be evaluated.