Candida albicans is a part of the human microbiome that inhabits the gastrointestinal tract (GI tract), oral cavity, and vagina of an individual. It is an opportunistic pathogen that causes fungal infections– under favorable conditions.
Candida albicans is a dimorphous, gram-positive, commensal yeast-like fungus. When observed under the microscope, the yeast may appear as; either smooth colonies containing white patchy-round cells or grey-coloured flat colonies comprising opaque rod-shaped cells. These two phenotypic forms are known to express different antigenic properties and have different affinities for various parts of the body. This phenotypic variation of C. Albicans permits it to be exceptionally adaptive to the changes in the environment.
Infections caused by Candida albicans
Candida albicans are known to cause numerous infections, but urinary yeast infections, genital yeast infections, oral thrush, mucocutaneous candidiasis, and deadly invasive candidiasis are some quotidian infections, to name a few. It remains as a commensal yeast under normal health conditions but may become pathogenic in immunocompromised individuals.
Invasive Candidiasis (IC)
Invasive candidiasis (IC) is a life-threatening fungal infection in contrast with various infections caused by C. albicans. The yeast gains entry into the bloodstream–infects blood, eyes, brain, bones, heart and various body parts. The bloodstream infection of yeast is termed as candidemia. IC is not contagious and does not spread from person to person. It is most prevalent in hospitalized patients; is transmissible by health care staff, or via tainted medical devices.
- Symptoms: An individual suffering from IC is heretofore are ailing with various morbid conditions, as such, symptoms may be undetectable. However, the most typical symptoms are fever and chills which may remain unchanged even after treatment with antibiotics. Moreover, the symptoms pertaining to IC may involve low blood pressure, stomach pain, muscle pain, skin rash, and fatigue to name a few.
- Treatment: IC can be treated with antifungal medications. To impede IC, individuals suffering from cancer, organ or bone marrow transplants may be administered with antifungal medications. The dosage and type of antifungal medication applicable for the treatment of IC can be determined by factors such as severity and location of the infection, immune status, and age of the patient. The majority of adults are prescribed echinocandin antifungal drugs like anidulafungin, caspofungin, or micafungin; either of them is administered via veins (intravenously or IV). In certain circumstances, treating an individual with amphotericin B, Fluconazole, and various antifungal drugs/medications may be the opposite.
Pathogenicity of Candida albicans
- albicans is a polymorphic yeast commensal that has the ability to grow either as:
- an elliptical budding fungus with elongated and ellipsoid cells showing septal constrictions (pseudohyphae), or
- as true hyphae, showing parallel-walled structures.
Moreover, during the transition state, C. albicans may form white, opaque cells or spore-like structures with thick walls. These structures are known as chlamydospores. During infection, hyphae and yeasts are the typical forms that are to be observed; these forms are distinct in their properties.
The yeast–hyphal transition is referred to as dimorphism; it is suggested that both of these dimorphic forms are essential for the pathogenicity of C. albicans.
Drugs used for the treatment of infections by Candida albicans
Antifungal drugs used for the treatment largely include:
- Azole drug variants such as fluconazole and miconazole. These drugs are known to restrain the activities of ergosterol by hindering the enzyme responsible for its synthesis.
- Echinocandins act by hindering the activities of an enzyme glucan synthase responsible for the osmotic lysis of the fungal cell.
- Polyenes contrarily interrupt the flucytosine and ergosterol; disrupt the enzyme thymidine kinase (TK).
- Ally amines are known to cause disruptions of the cell membrane.
- Griseofulvin prevents apoptosis by hindering the formation of the microtubule.
Candida albicans is a commensal yeast that may become pathogenic in immunocompromised individuals. Several factors are known for the virulence of the yeast-like proteases secretion, invasins and adhesins expression, and dimorphism. Recent studies have shown that heat shock responses which include the usage of small and major heat shock proteins, have transpired as propitious drug targets.
Recent findings also suggest that morin utilization might be considered a potential therapeutic drug for candidiasis, an infection caused by Candida albicans.