ANTIFUNGAL SUSCEPTIBILITY OF OPPORTUNISTIC MEMBERS OF THE ORDER MUCORALES

Background and Aim:Mucoralean fungi are among emerging oppourtunictic fungi with high level of mortality in susceptible patients, specially when left untreated. Number of mucormycosis cases have been rapidly increasing in recent decades. Correct identification of the etiological agents and proper choice of antifungals will lead to better management of this infection and will reduce the morbidities.Methods:The in vitro susceptibilities of 45 molecularly identified strains of Mucorales to eight antifungals (amphotericin B, terbinafine, itraconazole, posaconazole, voriconazole, caspofungin, micafungin, and 5-fluorocytosine) were tested. These strains belong to the following species: Cunninghamella (n= 8), Rhizopus (n=12), Mucor (n=7), Syncephalastrum (n= 8), Lichtheimia (n=10). Strains were formerly identified based on the nuclear ribosomal large subunit (ITS).Results:The susceptibility profile was variable among different species and different antifungals. Amphotericin B was the most active drug for most species. Posaconazole was the second most effective antifungal agent but showed reduced activity in Mucor and Cunninghamella strains, while voriconazole lacked in vitro activity for most strains. Cunninghamella also comprised strains resistant to all azoles but was fully susceptible to terbinafine. In contrast, the Lichtheimia and Syncephalastrum species completely lacked strains with reduced susceptibility for these antifungals. Mucor species were more resistant to azoles than Rhizopus species. Complete or vast resistance was observed for 5-fluorocytosine, caspofungin, and micafungin.Conclusion:Accurate molecular identification of etiologic agents is compulsory to predict therapy outcome. For species of critical genera such as Mucor and Rhizopus, exhibiting high intraspecific variation, susceptibility testing before the onset of therapy is recommended.

کلیدواژه ها:

Antifungal susceptibility ، Amphotricin B ، mucormycosis