Genotypic Characterization of Environmental Isolates of Cryptococcus gattii from Puerto Rico

Abstract

Cryptococcus neoformans and Cryptococcus gattii are found in distinct environments with some overlap around different parts of the world. However, no systematic surveys of these two pathogens have been reported from Puerto Rico, a tropical island uniquely situated between mainland USA and countries in South America. We carried out an exhaustive environmental survey in southwestern Puerto Rico for pathogenic Cryptococcus species. Twenty-two presumptive isolates of C. gattii from cacti and tree detritus were characterized in detail by physiological and molecular methods and seventeen strains were confirmed as C. gattii. Cryptococcus gattii isolates were haploid and majority of them were MATa [corrected] strains. Sixteen out of seventeen C. gattii isolates belonged to VGII/AFLP6 genotype while one isolate was a VGIV/AFLP7 genotype. The results are significant as Puerto Rico strains are distinct from VGIII/AFLP5 strains reported from Southern California, but similar to C. gattii VGII/AFLP6 molecular type implicated in recent outbreaks of cryptococcosis in Pacific Northwest and British Columbia, Canada, but different in its M13 fingerprinting, and a common genotype in South America.

The persistence of multifocal colonisation by a single ABC genotype of Candida albicans may predict the transition from commensalism to infection

“…First described in 1999 by McCullough et al, ABC genotyping was developed on the basis of the presence or absence of an insert in the DNA that encodes for the 25S ribosomal RNA gene among different C. albicans genotypes (McCullough et al 1999). Microsatellite typing using primer M13, which amplifies short tandem repeats, was first employed to type Cryptococcus strains in Brazil (Casali et al 2003) and has been extensively used to type this encapsulated yeast (Loperena-Alvarez et al 2010, Pedroso et al 2010, Ferreira-Paim 2011. Nevertheless, only a few studies have employed the M13 primer to type C. albicans (Bartie et al 2001).…”

The Search for the Natural Habitat of Cryptococcus gattii

“…In this issue of Mycopathologia, Loperana-Alvarez et al [1] report that they have isolated the pathogenic yeast Cryptococcus gattii from trees and succulent plants in Puerto Rico, a tropical island in the Caribbean.…”

“…Earlier attempts to isolate C. gattii from the environment in Puerto Rico and Cuba were unsuccessful [10,11]. Loperana-Alvarez and colleagues investigated the same regions in Puerto Rico that were sampled two decades ago, but this time both pathogenic Cryptococcus species were found [1,11]. Trees that were known to be positive for C. gattii, like the almond (Terminalia cattapa) and mango tree (Mangifera indica), were found to yield C. gattii [1,7,9].…”

“…Loperana-Alvarez and colleagues investigated the same regions in Puerto Rico that were sampled two decades ago, but this time both pathogenic Cryptococcus species were found [1,11]. Trees that were known to be positive for C. gattii, like the almond (Terminalia cattapa) and mango tree (Mangifera indica), were found to yield C. gattii [1,7,9]. Strikingly, the majority of C. gattii strains were isolated from lesions on Cephalocereus royenii cacti.…”

“…Strikingly, the majority of C. gattii strains were isolated from lesions on Cephalocereus royenii cacti. This cactus species belong to a group of succulent plants that are known to harbor non-pathogenic Cryptococcus yeasts [1]. With the knowledge that C. gattii can survive in lesions of succulent plants, it may be a matter of time before cacti in other geographic regions of the world will be found to harbor C. gattii.…”