Evaluation of heteroresistance phenomenon among clinical Brazilian Cryptococcus neoformans

Ruiz, M.S.R., Ruiz, M.S., Strob, A.J., Melhem, M.S.C.

Author address: 

Adolfo Lutz Institute, SíƒO PAULO, Brazil


The heteroresistance is the simultaneous occurrence of resistant and susceptible populations in a single isolate to a specific antifungal agent. The aim of this study was to analyze the resistance of cryptococcosis agent, Cryptococcus neoformansthrough the technique for heteroresistance detection to fluconazole (FCZ). We have analyzed 68 clinical samples of C. neoformansisolated from blood or cerebrospinal fluid, maintained under 20 °C at the Culture Collection of Mycology Unit, Adolfo Lutz Institute. For heteroresistance research, the cells of each isolate were suspended in sterile saline (1x103 to 5x103 CFU/mL) before being plated on potato dextrose agar (PDA) plates containing FCZ at concentration 8mg/mL. After 72 h of incubation at 35 °C, the growth was evaluated and the diameters of the colonies were measured as recommended by Yamazumi et al. (2003). We named arbitrary large (L) and small (S) colonies observed in a single isolate, respectively for those having >4mm and

abstract No: 


Full conference title: 

3rd Trends in Medical Mycology
    • TIMM 3rd (2011)