Update on Antimicrobial Agents (Antifungals & Antivirals) PDF

Update on antimicrobial agents (Antifungals & Antivirals) Ahmed Sherif Attia, Ph.D. Professor of Microbiology & Immunology Faculty of Pharmacy, Cairo University, Cairo, Egypt [email protected] 1  Antifungals Outline Antiv...

Update on antimicrobial agents (Antifungals & Antivirals) Ahmed Sherif Attia, Ph.D. Professor of Microbiology & Immunology Faculty of Pharmacy, Cairo University, Cairo, Egypt [email protected] 1  Antifungals Outline Antivirals 2  Antifungals https://www.youtube.com/watch?app=desktop&v=YhQu-ZgNs8g 3 How do they work? Direct killing Preventing growing They target structures or functions that are necessary in fungal cells but not in human cells Fungal cell membrane Fungal cell wall Upon compromise, the cell bursts and dies. 4 Routes of Administration Oral Topical Intravenous Factors The drug The type of infection The severity of infection 5 1- Azoles Inhibit cytochrome P450-dependent enzymes involved in the biosynthesis of cell membrane sterols “ergosterol” Imidazoles Ketoconazole, Clotrimazole, & Miconazole Triazoles Fluconazole, Itraconazole, Posaconazole, & Voriconazole 6  2- Polyenes Bind to ergosterol and inhibit its cellular functions with (amphotericin B) or without (natamycin) permeabilizing the fungal membrane. Amphotericin B: various formulations are available to treat aspergillosis, blastomycosis, cryptococcosis, mucosal or invasive Candida infections, and coccidioidomycosis Nystatin: Candida infections of the skin and mouth 7 3- Allylamines Competitive inhibition of squalene epoxidase, blocking the conversion of squalene to lanosterol, leading to squalene accumulation and ergosterol depletion in the cell membrane Terbinafine: often used to treat fungal infections of the skin. 8  4- Echinocandins Inhibiting beta-(1,3)-D-glucan synthase, an enzyme that is necessary for the synthesis of an essential component of the cell wall “Glucan” of several fungi. Anidulafungin & Micafungin for mucosal and invasive Candida infections Caspofungin for mucosal and invasive Candida infections & aspergillosis 9  Miscellaneous Flucytosine It is metabolized to 5-fluorouracil within fungal organisms. The 5-fluorouracil is extensively incorporated into fungal RNA and inhibits the synthesis of both DNA and RNA. Treat systemic infections with Candida or Cryptococcus species. https://www.researchgate.net/publication/355706649_Molecular_Mechanisms_of_5- Fluorocytosine_Resistance_in_Yeasts_and_Filamentous_Fungi/figures?lo=1&utm_source=google&utm_medium=organic 10 Miscellaneous Griseofulvin Fungistatic action by inhibition of microtubule assembly; Thus, affecting the formation of the mitotic spindle, causing abnormal chromosomal rearrangements and, as a final consequence inhibits fungal replication It can be used to treat infections of the skin, hair, and nails 11  In summary 12 https://www.lecturio.com/concepts/echinocandins/  Antivirals https://www.freepik.com/premium-vector/doctor-full-antiviral-protective-equipment-wearing- 13 superhero-red-cape-triumphs-coronavirus_29281969.htm Steps of viral replication 15