Microbiology Practice Exam

Fungi that cause systemic mycoses typically inhabit which environment?

1. Human skin

2. Animal hosts

3. Soil as saprophytes

4. Water bodies

The correct answer is: Soil as saprophytes

Systemic mycoses, which are serious fungal infections that can affect internal organs, predominantly originate from environmental reservoirs in soil. Fungi that cause these types of infections are often saprophytic, meaning they derive nutrients from decaying organic matter in the soil. Notable examples include organisms like Histoplasma capsulatum, which is found in soil contaminated with bird or bat droppings, and Coccidioides immitis, which is prevalent in arid regions of the southwestern United States. While human skin is a site for many superficial fungi and certain pathogenic fungi may interact with animal hosts, systemic mycoses are not primarily linked to these environments. Water bodies can host various pathogens, but they are not the primary reservoir for systemic mycoses, making the soil as saprophytes the key habitat from which these fungi are commonly acquired. Understanding the ecological niches of fungi helps clarify their modes of transmission and potential risk factors for infection in humans.