Aim: To compare and contrast how different antifungal medicines affect fungal infections.
Hirona (Kate) Kato
Sitanun (Winnie) Sae-Seung
A fungus (plural: fungi) is an eukaryotic organism. Examples of fungi include yeasts, moulds and mushrooms. Fungi are among the most widely distributed organisms on Earth and are found free-living in soil or water, while others form parasitic or symbiotic relationships with plants or animals.
The study of fungi is known as mycology, and although fungi have more in common with animals than plants, mycology is considered to be a branch of botany. Like animals and most bacteria, fungi derive energy from the consumption of organic substances, opposed to gaining energy from light as plants do through photosynthesis.
Most fungi are large enough to be seen with the naked eye. However, some fungi are microscopic organisms and studied within the field of microbiology. Some microscopic fungi such as yeast are used in the food and drink industry in order to produce bread, beer and wine. Other fungi are important in the pharmaceutical and biotechnology industries and are used in the production of antibiotics and various enzymes.
This project is primarily focusing on fungi within the medical world.
Fungi are microbes that exist in nature as one-celled yeasts or as branching filamentous molds. Only about 20 to 25 species of fungi are common causes of infection. Fungal tests detect infections and sometimes identify the fungus and help guide treatment. Fungal infections range from superficial skin infections to serious deep tissue, blood, lung, or systemic diseases.
Many pathogenic fungi are parasitic in humans and are known to cause diseases in humans and other animals. Human diseases caused by fungi include athlete’s foot, thrush, ringworm, and coccidioidomycosis. Fungal infections (or mycotic infections) in humans and domesticated animals are caused when fungus invades the tissues causing superficial, subcutaneous, or systemic disease and may affect the skin surface or the internal organs:
The common yeast infections are not actually caused by yeast, but a yeast-like fungus called Candida albicans. C. albicans normally inhabits the human mouth, throat, colon, and reproductive organ, but does not cause disease when in ecological balance with other microbes within the digestive system. However, age or hormonal changes can cause an uncontrollable manner of growth that cannot be controlled by the body’s defense systems. Yeast infections on the skin are called cutaneous candidiasis. They cause yeast on the skin to grow more actively and this affects many different people. Yeast rash often occurs in warm, moist areas, and causes a rash on the afflicted area. However, they are not contagious. People who have diabetes, are obese, or are taking antibiotics are more at risk of contracting a yeast infection.
Factors that should be considered when choosing Anti-microbial drugs:
In current Antifungal drugs, there are different classes of drugs that target different aspects of fungi and yeast including: the plasma membrane, sterol biosynthesis, DNA biosynthesis, and β-glucan biosynthesis. Human enzymes are different enough from fungal enzymes such as sterol biosynthetic enzymes that the drugs will target the fungus/yeast without targeting human cells. As fungi make β-glucan but humans don’t, drugs that target the biosynthesis of β-glucan only have minor side effects.
Fluconazole is an antifungal medication that can treat a variety of fungal infections: including but not limited to, candidiasis, blastomycosis, coccidioidomycosis, cryptococcosis, histoplasmosis, dermatophytosis, and pityriasis versicolor. In certain cases, Fluconazole can be used a preventative measures in high risk patients. It is one of the most effective and safe medicines, as stated in the World Health Organization (WHO) List of Essential Medicines.
Usage and Side Effects:
Fluconazole is both an oral medication and an injection.
Common Side Effects:
The Drug Fluconazole causes damage to the membrane of yeast and fungal cells by stopping cell growth and multiplication. This either removes the infection or stops the development of infections. However, it is possible that some of the yeast or fungus will remain after the infection is gone. Therefore, prescribed doses of medicine are designed in order to ensure the complete removal of infection, and it is imperative to finish the dosage.
Echinocandins is an antifungal drug which acts to inhibit the β (1, 3)-D- glucan synthase. The β (1, 3)-D- glucan synthase is a necessary enzyme to the fungal cell wall. Without this enzyme the fungus is unable to have a cell wall which has a good structure. And without the fungus’s ability to synthesize the enzyme, this leads to osmosis instability which ultimately leads to cell death once the compound can not perform necessary exchanges. Fungal cell wall is different to mammals’ cell membrane as they are composed of different compounds, thus this drug will only target fungus.”Echinocandins are a group of semisynthetic, cyclic lipopeptides with an N-linked acyl lipid side chain.” (Grover) The drug is administered into the veins. The only fungus that has, thus far, shown a resistance to Echinocandins has been observed in C. glabrata and C. parapsilosis. However, this is not common.
Tioconazole is an imidazole, which is an organic compound with a formula of “C3N2H4” is an anti-fungal agent which stops the growth of human pathogenic yeasts. It does it by interfering with the production of enzymes and other substances which are needed to preserve the cell membrane. It inhibits the production of an enzyme called ergosterol, leading to increased cellular permeability. Cell permeability means the permitting of substances into and out of the cell. It will not work for bacterial or viral infections. Tioconazole may also inhibit endogenous respiration, the transformation of yeasts to mycelial forms and the uptake of calcium and potassium ions across the cell membrane by blocking the ion transport pathway known as the Gardos channel. This drug is effective only for infections caused by fungal organisms. The drug’s main use is to cure yeast infection, especially vaginal yeast infections.
What is Fungus?
What is a Fungal Infection?
What factors should be considered when choosing Antimicrobial drugs?
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