Coccidioides spp. are dimorphic fungal pathogens endemic to the semiarid regions of North, Central, and South America. Currently, direct smear and culture are the most common means of identifying Coccidioides spp. While these methods offer relatively sensitive and specific means of detecting Coccidioides spp., growth in culture may take up to 3 weeks, potentially delaying the diagnosis and initiation of appropriate antifungal therapy. In addition, growth of the organism represents a significant safety risk to laboratory personnel. The need for a rapid and safe means of diagnosing coccidioidomycosis prompted us to develop a real-time PCR assay to detect Coccidioides spp. directly from clinical specimens. Primers and fluorescent resonance energy transfer (FRET) probes were designed to target the internal transcribed spacer 2 region of Coccidioides. The assay's limit of detection is below 50 targets per reaction. An analysis of 40 Coccidioides sp. clinical isolates grown in culture demonstrated 100% sensitivity of the assay. A cross-reactivity panel containing fungi, bacteria, mycobacteria, and viruses was tested and demonstrated 100% specificity for Coccidioides spp. An analysis of 266 respiratory specimens by LightCycler PCR demonstrated 100% sensitivity and 98.4% specificity for Coccidioides spp. compared with culture. Analysis of 66 fresh tissue specimens yielded 92.9% sensitivity and 98.1% specificity versus those of the culture method. The sensitivity of the assay testing 148 paraffin-embedded tissue samples is 73.4%. A rapid method for the detection of Coccidioides spp. directly from clinical material will greatly assist in the timely diagnosis and treatment of patients, while at the same time decreasing the risk of accidental exposure to laboratory personnel.
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http://dx.doi.org/10.1128/JCM.01776-06 | DOI Listing |
Environ Health Perspect
January 2025
Department of Epidemiology, Biostatistics, and Environmental Health, School of Public Health, University of Nevada, Reno, Reno, Nevada, USA.
Background: Coccidioidomycosis, caused by inhalation of spp. spores, is an emerging infectious disease that is increasing in incidence throughout the southwestern US. The pathogen is soil-dwelling, and spore dispersal and human exposure are thought to co-occur with airborne mineral dust exposures, yet fundamental exposure-response relationships have not been conclusively estimated.
View Article and Find Full Text PDFmSphere
January 2025
Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, USA.
spp. are part of a group of thermally dimorphic fungal pathogens, which grow as filamentous cells (hyphae) in the soil and transform to a different morphology upon inhalation into the host. The host form, the spherule, is unique and highly undercharacterized due to both technical and biocontainment challenges.
View Article and Find Full Text PDFMed Mycol J
December 2024
Department of Infectious Diseases, Nagasaki University Graduate School of Biomedical Sciences.
bioRxiv
January 2025
University of Michigan, School of Public Health, Department of Epidemiology, Ann Arbor, MI 48109.
medRxiv
October 2024
Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, CA, USA.
Coccidioidomycosis, a fungal disease caused by soil-borne spp., exhibits pronounced seasonal transmission, with incidence in California typically peaking in the fall. However, the influence of climate on the timing and duration of transmission seasons remains poorly understood.
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