A study on fungal speciation and drug susceptibility testing

Abstract

Fungal infections affect many people but most of these do not come to light as they are mild in clinical presentation. Candidiasis is the frequent fungal infection involving mucosa, skin, nails and internal organs caused by different species of Candida and Candida albicans being the prototype. The clinical manifestations vary with duration and severity. It occurs mostly as a comorbid disease with a primary disease or disorder. Candida comes under the phylum Fungi Imperfecti, order Moniliales and family Cryptococcaceae. Genus Candida comprises of 20 important species recognised as pathogenic in humans, of which 7 are renowned opportunistic pathogens. The following are some of the known species: Candida albicans, Candida tropicalis, Candida krusei, Candida glabrata, Candida guilliermondii, Candida parapsilosis, Candida lusitaniae, Candida kefyr, Candida rugosa, Candida dubliniensis and Candida viswanathii. Among all the fungi, 600 species are identified to be causing infections in human. Candida albicans being one of the normal human commensals may cause infections from mild to severe forms, which is influenced by molecules that helps in adhesion and invasion, hydrolases, yeast to hyphal transition, biofilms etc. In general, equal importance has not been give to fungal infections as is being given for bacterial infections. Nowadays newly emerging species are on the tract as to cause infections and their identification profile being indeterminate, which could be confirmed only by molecular methods. Overall C.tropicalis was the frequent species causing infections clinically and resistance was demonstrated against azoles and caspofungin by C.albicans and C.krusei. This may be due to extensive use of echinocandins as empirical therapy without susceptibility testing which can increase the development of resistance and may deduct treatment options. Hence, routine antifungal susceptibility testing has to be done. Out of all these things accurate epidemiological analysis and data can be provided regarding the burden of fungal infections around the globe. As tip of the iceberg, most of the fungal infections are not being reported as it is unnoticed without prominent clinical presentation and due to lack of complete documentation.