Occurrence of Cryptococcus neoformans and other yeast-like fungi in environmental sources in Bonaire (Dutch Caribbean)

Introduction We report here the presence of Cryptococcus neoformans, and other potentially pathogenic yeasts and yeast-like fungi in environmental sources in Bonaire.

Methods Seventy environmental samples comprising 40 samples of old pigeon droppings, 18 of woody debris from hollows of living trees of Caesalpinia (‘Divi Divi’), Ziziphus jujuba (Red Indian date), Tamarindus indica (Tamarind), Terminalia catappa (Tropical almond), Azadirachta indica (Neem) and 3 of other unidentified species of trees, 3 of latex from a rubber tree and 6 of coral dust were processed for isolation of pathogenic Cryptococcus spp. and other potentially pathogenic yeasts and yeast-like fungi. A variety of mycological media were employed. Identification of the isolates was done with conventional techniques and species identification was done by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Results Three of the 40 samples from old pigeon droppings yielded Cryptococcus neoformans, constituting the first record of environmental occurrence of this important pathogenic yeast in the Dutch Caribbean. Other potentially pathogenic yeasts and yeast-like fungi recovered from these environmental samples included 6 isolates each of Candida albicans, 8 of Candida parapsilosis, 4 each of Candida metapsilosis and Candida orthopsilosis, 2 each of Candida carpophila, Candida famata,Candida fabianii and Candida pelliculosa, 7 of Candida spp., 5 of Trichosporon spp. and 2 of Sporobolomyces spp.

Conclusions This study has demonstrated for the first time the occurrence of C. neoformans in a natural habitat in the Dutch Caribbean. The recovery of many species of potentially pathogenic yeast-like fungi and yeasts from environmental sources is remarkable.

Keywords Environmental yeasts, Cryptococcus neoformans, Candida spp., Trichosporon spp., Sporobolomyces spp.