Molecular identification of Coccidioides spp. in soil samples from Brazil

Regina Cl De Macêdo,Bodo Wanke,Maria As Cavalcante,Antônio D Filho,Fabio F Da Mota,Márcia S Lazéra,Kelsen D Eulálio,Liline Ms Martins,Alexandre S Rosado

doi:10.1186/1471-2180-11-108

Abstract

BackgroundSince 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.ResultsTwenty 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.ConclusionThis 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

Highlights

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
Coccidioidomycosis is a systemic mycosis acquired by inhalation of infective arthroconidia from Coccidioides immitis or C. posadasii [1], which are pathogenic species of dimorphic fungi that live saprobiotically in soil from arid regions of the western hemisphere [2]
They studied soil samples collected from a disturbed site in the San Joaquin river valley (California, USA) that was the possible source of an acute coccidioidomycosis outbreak [10]

Summary

Introduction

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. These two species are morphologically identical but genetically and Stewart & Meyer in 1932 reported the first isolation of C. immitis from soil, proving that this substrate is the primary source for coccidioidomycosis They studied soil samples collected from a disturbed site in the San Joaquin river valley (California, USA) that was the possible source of an acute coccidioidomycosis outbreak [10]. It is an expensive methodology with relatively low de Macêdo et al BMC Microbiology 2011, 11:108 http://www.biomedcentral.com/1471-2180/11/108 sensitivity, and the results take a long time to obtain, usually up to 45 days [7,12,13]

Methods

Discussion

Conclusion