Comparative study of two culture conservation methods in medical mycology

The efficiency of two fungal conservation methods was compared: Suspension in sterile distilled water and subcultures on potato dextrose agar (PDA) sl ants at 4 degrees C. One hundred and eleven strains corresponding to 84 dif ferent-species of microorganisms studied in medical mycology were evaluated . The efficiency of each method was estimated by the survival percentage an d the preservation of the morphological features of each strain within a se ven-year period. From the 111 strains, 79 (71.2%) were preserved viable in water, compared to 86 (77.5%) strains preserved by subculture on PDA slants . Concerning morphological features 75 of the 79 water viable strains (94.9 %) conserved their morphology. In contrast, only 60 of the 86 strains (69.8 %) conserved their typical morphology by the PDA subculture method. The wat er conservation method offers important benefits over serial subculture suc h as: Minimal pleomorphism, simple, rapid and requiring few materials. Thus , the water conservation method is recommended for laboratories where speci alized conservation equipment is not available.