Isolation of Cryptococcus spp. from several environmental niches in São Luís, MA

Cryptococcosis is an invasive mycosis triggered by a complex of fungal pathogens present in various environmental niches. Cryptococcus neoformans, C. gattii, and emerging pathogens such as C. laurentii and C. albidus are found in aged excreta of Columba livia (pigeon), its natural disseminator. As the pigeon population has increased in São Luís, the objective of this research was to demonstrate the presence of Cryptococcus spp. in the excreta of C. livia in public environments. Twenty-three samples were collected at 14 sites, dispensed into conical tubes, homogenized with saline and chloramphenicol, and allowed to rest until processing. Twenty-four hours after collection, aliquots were distributed in a fungal culture medium and incubated. The macromorphological examination revealed levaduriform, mucoid, bright, isolated colonies compatible with Cryptococcus spp. In the micromorphological examination, 11 of the 23 samples (42.85%) showed the presence of cells with a thick, refringent capsule and mucopolysaccharide around the blastoconidia, typical of Cryptococcus spp. fungi. The other samples (57.14%) were negative for the fungus. The environmental isolation of this fungus in public areas is relevant to public health since the growing pigeon population in São Luís increases the risk of exposure and infection by dispersion of infectious propagules in the environment.