Fungi are eukaryotic organisms that differ significantly from bacteria. They possess a rigid cell wall containing chitin and glucans, rather than the peptidoglycan found in bacteria. Their cell membranes contain ergosterol instead of cholesterol. In clinical practice, medically important fungi generally exist in two main morphological forms: yeasts and molds.
Pathogenic fungi cause infections known as mycoses. While many fungi are harmless saprophytes living in the soil or on human skin, certain species become pathogenic when host immunity drops or skin integrity is compromised.
Superficial and cutaneous mycoses are infections limited to the outermost layers of the skin, hair, and nails. Because these tissues contain dead, keratinized protein, the fungi responsible for cutaneous infections are called dermatophytes.
Transmission occurs through direct contact with infected humans, animals, or contaminated fomites like combs and shared clothing. Warmth and moisture greatly encourage their growth.
Systemic mycoses are deep-seated infections that can affect internal organs and spread throughout the body. They are divided into endemic systemic infections caused by true primary pathogens and opportunistic infections that exploit weakened immune systems.
Endemic dimorphic fungi like *Histoplasma capsulatum* live in soil and are inhaled into the lungs, mimicking tuberculosis. In contrast, opportunistic fungi do not usually cause severe disease in healthy individuals. *Candida albicans* can overgrow on mucosal surfaces during antibiotic therapy or in pregnancy. *Cryptococcus neoformans*, found in pigeon droppings, can cause severe meningitis in patients with advanced HIV/AIDS. *Aspergillus* species produce spores that can colonize lung cavities in immunocompromised hosts, leading to severe respiratory compromise.
Accurate diagnosis of fungal infections relies on a combination of clinical evaluation and laboratory investigation. Because fungal cultures can take days or weeks to grow, rapid microscopic examination is often the first step.
Treating mycoses requires targeted pharmacotherapy based on the infection site and severity. Because fungi are eukaryotic, medications must exploit biochemical differences between human and fungal cells, such as fungal ergosterol.
Midwives and nurses play a vital role in patient management. This includes educating patients on completing the full course of topical creams to prevent recurrence, monitoring liver function tests during long-term oral azole therapy, and observing patients receiving intravenous Amphotericin B for infusion-related fevers and chills.