Viability and molecular authentication of Coccidioides spp. isolates from the Instituto de Medicina Tropical de São Paulo culture collection, Brazil

Abstract

SUMMARYCoccidioidomycosis is an emerging fungal disease in Brazil; adequate maintenance and authentication of Coccidioides isolates are essential for research into genetic diversity of the environmental organisms, as well as for understanding the human disease. Seventeen Coccidioides isolates maintained under mineral oil since 1975 in the Instituto de Medicina Tropical de São Paulo (IMTSP) culture collection, Brazil, were evaluated with respect to their viability, morphological characteristics and genetic features in order to authenticate these fungal cultures. Only five isolates were viable after almost 30 years, showing typical morphological characteristics, and sequencing analysis using Coi-F and Coi-R primers revealed 99% identity with Coccidioides genera. These five isolates were then preserved in liquid nitrogen and sterile water, and remained viable after two years of storage under these conditions, maintaining the same features.

Molecular and phenotypic reidentification of Sporothrix schenckii clinical isolates preserved under mineral oil for 34 to 64 years in a culture collection in Brazil

“…Culture collections are conservation centers for ex situ genetic resources whose main objectives include the preservation and supply of biological material and associated information for scientific and industrial research and development ( Onions et al., 1983 ). The preservation methods have the purpose of maintaining the viability and the morphological, physiological and genetic characteristics of the isolates ( Onions et al., 1983 ; Borba et al., 1992 ; Borba and Rodrigues, 2000 ; Cavalcanti et al., 2013 ).…”