Preservation of fungal cultures of medical importance in distilled water

[摘要] Introduction: causal agents of the main human myicoses have been preserved in the culture collection of pathogenic fungi at "Pedro KourÍ" Tropical Medicine Institute, a national reference center, with the purpose of using them for medical microbiology diagnoses, research and teaching. Preservation of fungal cultures in sterile distilled water, or Castellani's method, has been endorsed as a method ensuring high rates of strain viability, purity and stability, low costs and great simplicity. It is therefore an advantageous alternative for the maintenance of microorganisms in many laboratories. Objective: present the results obtained from the preservation in sterile distilled water of the main fungal species included in the collection. Methods: an evaluation was conducted of the viability, purity and stability of the main morphological and physiological characteristics of 240 strains of different fungal species from the collection, which had been preserved in sterile distilled water. Results: 80 % of the cultures had retained their viable status without any contamination. The best results corresponded to the preservation of fungi producing abundant conidia (97 % recovery) and yeasts (83 %), followed by dermatophytes (69 %) and dimorphic fungi (68 %). In 8 genera, recovery of viable strains was 100 %, and in 17 it was above 60%. Preservation time was 15-20 years. A web-based digital database was created for the collection. Conclusions: Castellani's is the method of choice for the preservation of fungal cultures in resource-limited laboratories.

[学科分类] 传染病学

[关键词] pathogenic fungi;preservation in distilled water;fungal culture preservation methods;Castellani's method;fungal culture collections