Antimicrobial Pharmacology PDF

PHARMACOLOGY AND TOXICOLOGY ANTIMICROBIAL PHARMACOLOGY WO N G C H U N K E U N G 21 OCT 2024 1 WHAT IS THE DIFFERENCE BETWEEN ANTIBIOTICS AND ANTIMICROBIAL DRUGS? Antimicrobials – A group of agents aim of reducing the possibility of infection and sepsi...

PHARMACOLOGY AND TOXICOLOGY ANTIMICROBIAL PHARMACOLOGY WO N G C H U N K E U N G 21 OCT 2024 1 WHAT IS THE DIFFERENCE BETWEEN ANTIBIOTICS AND ANTIMICROBIAL DRUGS? Antimicrobials – A group of agents aim of reducing the possibility of infection and sepsis Antibiotics – Derived from moulds – Or are made synthetically – A group of agents aim of killing bacteria (bactericidal) or preventing their multiplication (bacteriostatic) https://www.tasnimnews.com/en/news/2018/01/31/1643315/for-children-with-respiratory- infections-antibiotics-with-narrower-targets-are-better 3 BASIS OF ANTIBIOTICS ACTION Various antibiotics act by interfering with: – Cell wall synthesis – Plasma membrane integrity – Nucleic acid synthesis – Ribosomal function and – Metabolic pathways of bacteria, such as folate synthesis 6 β-LACTAM ANTIBIOTICS Examples are the penicillin, cephalosporin, and carbapenem, etc Antibiotics all contain a β- lactam ring Work by inhibiting the last step in bacterial cell-wall peptidoglycan synthesis https://en.wikipedia.org/wiki/Beta-lactam_antibiotics 9 MODE OF ACTION FOR BACITRACIN Bacitracin is a complex polypeptide produced by Bacillus subtilis (Gram-positive bacilli, catalase-positive, normally present in the environment, considered non-pathogenic for humans) It inhibits peptidoglycan synthesis in a step of bacterial cell wall synthesis Peptidoglycan is an envelope surrounds the cytoplasmic membrane of most bacterial species 16 Short question ANTIBIOTICS ACT BY INTERFERING WITH FUNCTION OF PLASMA MEMBRANE Polymyxins - Such as Polymyxin B and colistin (Polymyxin E) – Disrupts the outer cell membrane – Binds and neutralizes lipopolysaccharide – Inhibits respiration of Gram-negative bacterial cells Lipopeptide (Such as Daptomycin) – Bind to bacterial membranes – Leading to a rapid depolarization of the membrane potential. – Loss of membrane potential causing the inhibition of DNA, RNA and protein synthesis – Daptomycin treats infections caused by Gram- positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin- https://onlinelibrary.wiley.com/doi/full/10.1002/jppr.1435 resistant Enterococci (VRE). 19 ANTIBIOTICS ACT BY INTERFERING WITH FUNCTION OF RIBOSOMES https://open.oregonstate.education/microbiology/chapter/14-2mechanisms-of-antibacterial-drugs/ 23 ANTIBIOTICS ACT BY AFFECTING THE DNA AND RNA OF BACTERIA DNA Synthesis (Fluoroquinolones) Ciprofloxacin Levofloxacin Moxifloxacin RNA Synthesis Rifamycin 31 WHAT IS RIFAMYCIN? Antibiotics act by affecting the RNA Synthesis of bacteria Particularly effective against mycobacteria Treat tuberculosis, leprosy, and mycobacterium avium complex (MAC) infections Common side effects of rifamycin may include: Constipation and headache 38 WHAT IS RIFAMYCIN? Synthesized either artificially or naturally by the bacterium Amycolatopsis rifamycinica Includes the "classic" rifamycin drugs as well as the Rifamycin derivatives rifampicin (or rifampin), rifaximin, rifabutin, rifapentine and rifalazil 39 ANTIBIOTICS ACT BY INTERFERING WITH METABOLIC PATHWAYS OF BACTERIA Folic acid synthesis Sulfonamides Sulfones Trimethoprim Mycolic acid synthesis Isoniazid 40 SIDE EFFECTS OF TOPICAL ANTIFUNGAL AGENTS The following side effects may occur: Burning Stinging Swelling Irritation Redness 47 & Short ROUTES OF ADMINISTRATION FOR ANTIVIRALS Most antivirals are oral drugs Other common routes of administration for antiviral medications includes: – Topical (skin) creams – Eye drops – Small-particle aerosol https://foto.wuestenigel.com/wp-content/uploads/api/herpes-on-the-lower-lip-of-a-man.jpeg – IV into a vein, etc DRUGS FOR COMMON VIRAL SKIN INFECTION https://open.oregonstate.education/app/uploads/sites/8/2019/06/Fig.-16.21.png 54