Proper Care and Feeding of Coccidioides: A Laboratorian's Guide to Cultivating the Dimorphic Stages of C. immitis and C. posadasii

Abstract

Coccidioidomycosis (“Valley fever”) is caused by Coccidioides immitis and C. posadasii. These fungi are thermally dimorphic, cycling between mycelia and arthroconidia in the environment and converting into spherules and endospores within a host. Coccidioides can cause a broad spectrum of disease that can be difficult to treat. There has been a steady increase in disease, with an estimated 350,000 new infections per year in the United States. With the increase in disease and difficulty in treatment, there is an unmet need to increase research in basic biology and identify new treatments, diagnostics, and vaccine candidates. Here, we describe protocols required in any Coccidioides laboratory, such as growing, harvesting, and storing the different stages of this dimorphic fungal pathogen. © 2020 Wiley Periodicals LLC.

Basic Protocol 1: Growth and harvest of liquid mycelia cultures for extractions

Alternate Protocol 1: Large-volume growth and harvest of liquid mycelia cultures

Basic Protocol 2: Mycelial growth on solid medium

Alternate Protocol 2: Maintaining mycelial growth on solid medium

Basic Protocol 3: Harvesting and quantification of arthroconidia

Alternate Protocol 3: Long-term storage of arthroconidia

Basic Protocol 4: Parasitic spherule growth and harvest

Alternate Protocol 4: Obtaining endospores from spherules

Basic Protocol 5: Intranasal infection of murine models