Molecular identification of Coccidioides spp. in soil samples from Brazil.

BACKGROUND: Since 1991 several outbreaks of acute coccidioidomycosis (CM) were diagnosed in the semi-arid Northeast of Brazil, mainly related to disturbance of armadillo burrows caused by hunters while digging them for the capture of these animals. This activity causes dust contaminated with arthroconidia of Coccidioides posadasii, which, once inhaled, cause the mycosis. We report on the identification of C. posadasii in soil samples related to outbreaks of CM. RESULTS: Twenty four soil samples had their DNA extracted and subsequently submitted to a semi-nested PCR technique using specific primers. While only 6 (25%) soil samples were positive for C. posadasii by mice inoculation, all (100%) were positive by the molecular tool. CONCLUSION: This methodology represents a simple, sensitive and specific molecular technique to determine the environmental distribution of Coccidioides spp. in endemic areas, but cannot distinguish the species. Moreover, it may be useful to identify culture isolates. Key-words: 1. Coccidioidomycosis. 2. Coccidioides spp. 3. C. posadasii. 4. Semi-arid. 5. Semi-nested PCR.

Serotyping of 467 Cryptococcus neoformans isolates from clinical and environmental sources in Brazil: analysis of host and regional patterns.

Cryptococcus neoformans is an important zoopathogen, and it is one of the most prevalent lethal mycotic agents. Its polysaccharide capsule, synthesized in vivo and in vitro, is a virulence factor, contains predominantly glucuronoxylomannan, and is responsible for the antigenic differentiation of serotypes A, B, C, D, and AD. A total of 467 isolates of C. neoformans obtained from clinical and environmental sources from Brazilian regions were studied serologically by using the Crypto Check Iatron RM 304-K kit. Serotyping of the clinical isolates showed the following prevalences of the serotypes: A (77.95%), followed by B (18.2%), AD (1.3%), D (0.4%), C (0.2%), and untypeable (1.93%). The epidemiology of serotype A in the Brazilian southern and southeastern regions reproduces the picture observed worldwide. In contrast, serotype B was the most frequent agent of cryptococcosis in the northeastern region, occurring nearly equally in male and female healthy hosts. Among the isolates from environmental sources, serotypes A and B were found to occur in the hollows of tropical trees of the genera Cassia, Ficus, and MOQUILLEA: The few isolates from Eucalyptus camaldulensis debris were serotypes A and B and untypeable. Overall, no association with a specific host tree was identified for these serotypes, denoting a distinct ecoepidemiological regional pattern. The one serotype C isolate was recovered from a human immunodeficiency virus-negative host. Serotype AD predominated over serotype D among both clinical and environmental isolates.