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P24: Diagnosis, treatment and pathogenesis of mycoses, V. Arsic Arsenijevic



First Name:


Family Name:

Arsic Arsenijevic


Associated Professor

Name of organization:

University of Belgrade, School of Medicine, Institute of Microbiology and Immunology


Dr Subotica 1






Serbia and Montenegro


+381 11 685 584


+381 11 685 584




Proposed Title

Diagnosis, treatment and pathogenesis of mycoses


The human fungal infections are occurring, in the last two decades, with increased frequency in immunocompromised patients, particularly among those with malignancies and AIDS. Broad-spectrum antibacterial agents; the use of adrenal corticosteroids; cytotoxic chemotherapy; organs transplantation and prolonged use of indwelling catheters have contributed to this phenomenon. The significant increase in prevalence of resistance to antifungal agents has been noted in past 15 years with its implications for morbidity, mortality and health costs worldwide. Recent studies have demonstrated many factors of virulance in pathogenic fungi and also the ability of fungi to secrete prostaglandins (PGs). PGs could influence fungal biology by increasing the fungal virulance. At the same time, fungal PGs modulate immune response to fungi by inhibiting protective mechanisms or leading to immunopathological diseases. Substantial efforts of our study are focused on isolation, identification and collecting of fungal strains cousing: systemic candidosis, cryptococcosis, aspergillosis; the strains of skin associated Malassezia spp, and the strains isolated from patients with otomycoses. The susceptibility testing, determination of virulance factors and PGs production will be tested in all medically important isolated strains and the results will be compared. The aims of our study are the isolation, identification and collecting of fungi causing systemic infections, otomycoses and skin associated Malassezia spp. The laboratory diagnosis is planned to be determined by: cultivating methods (standard and newly developed media), using the antigens (ELISA) and antibodies (ELISA) dectection tests and with polymerase chain reaction for Candida, Cryptococcus, Aspergillus and Malassezia. Developing of self-made indirect immunofluoresency test for antibodies detection with intact fungal cells suspension is planned. Also, Malassezia spp are now recognized as possible factors in developing of immunopathologic skin diseases like atopic dermatitis (AD) and seborrheic dermatitis (SD). Under specific conditions these yeasts cause systemic infection in immunocompromised patients and neonates. However, the life cycle of Malassezia spp and the physiological requirements are still unresolved. Also the factors and mechanisms that enable this skin saprophyte to become associated with pathological changes are unknown. Considering that genus Malassezia has been recently enlarged to seven species, it has not been investigated whether a particular species of yeast is associated with above mentioned diseases. We have started to isolate the skin associated Malassezia spp from patients with SD, AD, pityriasis versicolor and healthy individuals (HI). For sampling the fungi we have been using the tape and swab methods and the isolation have been performed on Leeming-Notman and mDixon agar. The identification of seven Malassezia spp has be en obtained on the basis of morphological and biochemical caracteristics: catalase reaction, tolerance at 37oC an ability to utilize Tween 20, 40, 60 and 80 as sole lipid source. The special attention has been focused on developing a more detailed understanding of the mechanisms of antifungal resistance when it occurs, new antifungal drug “targets”, and methods to prevent the emergence and spread of resistant strains. The clinicians tend to depend, predominantly, on MIC breakpoints, to determine the susceptibility of an isolate, but acceptable testing methods and tentative breakpoints have been recently suggested (limited to yeast, particularly Candida spp.). Further studies are needed in developing the breakpoints for species other than Candida, for example Cryptococcus, Aspergillus and Malassezia. Antifungal susceptibility testing is planned to be performed on isolated strains of medical importance to the folowing antifungal drugs: amphotericin B, flycitosine, fluconasole and itraconazole, using the National Committee for Clinical and Laboratory Standards and E-test methodology. The progress has been made in identifying virulence for some fungal pathogens but much work remains to be done. The factors of virulence as melanin, capsule, proteinase, phospholipase activity, PGs and etc. will be determined in all isolated strains. Recent studies have demonstrated that pathogenic fungi have the ability to secrete PGs, which increase virulance of the fungus. For example, Candida albicans secrete PGs that enchance germ-tube formation and yeast to hypha transition. Similar relationship between secreted PGs and Cryptococcus neoformans, Aspergillus and Malassezia has not been established. Nevertheless, signalling pathway, which is responsible for increased capsule volume and melanin content, markers of virulence in Cryptococcus, is the activation of cAMP. Since PGs effect the various cells by increasing the amount of cAMP, it

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