Antibiotics and Anti-infectives Overview

Antibiotics - Anti-infectives

• Learning outcomes include knowing different therapeutic classifications, gaining knowledge of various drugs, identifying mechanisms of action, and actively participating in identifying market drugs.

Historical Background

• Sir Alexander Fleming discovered penicillin in 1929.
• Florey and Chain introduced penicillin therapy in 1938.
• Antibiosis means "against life".
• An antibiotic/antibiotic substance is a substance made by microorganisms that inhibits or destroys other microorganisms.

Anti-infective Agents

• Anti-infectives are designed to act selectively on foreign organisms that invade and infect the body.
• Anti-infectives range from antibiotics to antifungals, antiprotozoals, anthelmintics, antivirals, and antimycobacterials.

Characteristics of Antibiotics

• Antibiotics should possess selective toxicity.
• Antibiotics should have chemical stability.
• Antibiotics should have a slow rate of biotransformation and elimination.

Spectrum of Activity

• Narrow spectrum
• Broad spectrum
• Bacteriostatic drug
• Bactericidal

General Mechanisms of Action of Anti-infective Agents

• Some interfere with bacterial cell wall biosynthesis.
• Some inhibit protein synthesis.
• Some inhibit DNA/RNA synthesis.
• Some alter cell membrane permeability.

Common Adverse Reactions of Anti-infective Therapy

• Nephrotoxicity
• Gastro-intestinal
• CNS toxicity
• Hypersensitivity
• Superinfections

B-Lactam Antibiotics (Structure/Examples)

• Includes Penicillins, Cephalosporins, Carbapenems, and Monobactams
• Have a beta-lactam ring structure
• Inhibits cell wall synthesis

Penicillins (Examples/Classification)

• Narrow/Intermediate spectrum penicillins (Penicillin G, Penicillin V, Amoxicillin, Ampicillin)
• Broad spectrum penicillins (Aminopenicillin- Amoxicillin, Ampicillin, Bacampicillin)
• Penicillinase-resistant Penicillin /Narrow Spectrum (Cloxacillin, Nafcillin, Methicillin, Dicloxacillin, Oxacillin)
• Extended-spectrum penicillins (Carbenicillin, Mezlocillin, Piperacillin, Ticarcillin acid)
• Beta-lactamase inhibitors (Clavulanic, Sulbactam, Tazobactam)

Beta-Lactamase Inhibitors

• Class I inhibitors (Clavulanic acid, Sulbactam, and tazobactam)
• Class II inhibitor (Carbapenem derivative imipenem)

Cephalosporins

• Similar to penicillins in mechanism of action, chemical structure, and toxicities.
• Target bacterial cell wall transpeptidases and penicillin-binding proteins (PBPs) to cause cell wall lysis.
• Varying generations based on discovery time
• Oral: Cephalexin, Cephradine, Cefadroxil, Cefaclor, Cefprozil, Loracarbef, Cefuroxime axetil, Cefpodoxime proxetil, Cefixime
• Parenteral: Cephalosphorin containing cef; Cephradine, Cefuroxime, and Cefixime (oral and parenteral)

Classification

• First Generation (Cefalexin, Cephradine, Cefadroxil, Cephalothin, Cephapirin, Cefazolin)
• Second Generation (Cefaclor, Cefmetazole, Cefonicid, Cefotetan, Cefoxitin, Cefuroxime, Cefpodoxime, Cefprozil, Loracarbef, Cefamandole)
• Third Generation (Cefixime, Cefoperazone, Cefotaxime, Ceftazidime, Ceftibuten, Ceftizoxime, Ceftriazone)
• Fourth Generation (Cefepime, Cefpirome)
• Fifth Generation (Ceftaroline, Ceftobiprole)

Monobactams (Examples)

• Aztreonam Disodium (Azactam)
• Tigemonam

Polypeptides (Examples)

• Vancomycin Hydrochloride (Vancocin, Vancoled)
• Teicoplanin (Teichomycin A2, Targocid)
• Bacitracin

Membrane-Active Agents (-Polymixin, -Gramicidir)

• Polymixin
• Gramicidir

Agents Affecting Bacterial Protein Synthesis

• Aminoglycosides
• Macrolides
• Lincosamides
• Tetracyclines
• Chloramphenicols

Aminoglycosides (History/Examples)

• Discovered in 1939 from Streptomyces
• Kanamycin, Neomycin, Paromomycin, Gentamicin, Tobramycin, Netilmicin
• potent broad-spectrum activity
• Examples include Gentamicin (Garamycin), Tobramycin, Amikacin (Amikin), Netilmicin (Netromycin), Kanamycin (Kantrex), Streptomycin, Neomycin, Paromomycin, Spectinomycin

Macrolides (Examples)

• Clarithromycin (Klaricid, Klaz)
• Erythromycin
• Diritromycin (Dynabac)
• Azithromycin (Zithromax)

Lincosamides (Examples)

• Lincomycin Hydrochloride (Lincocin)
• Clindamycin Hydrochloride (Dalacin)
• Clindamycin Palmitate Hydrochloride (Cleocin Pediatric)
• Clindamycin Phosphate (Cleocin Phosphate)

Tetracyclines (Types/Examples)

• Short-acting (Tetracycline, Oxytetracycline)
• Intermediate acting (Demeclocycline, Methacycline)
• Longacting(Doxycycline)
• Includes Tetracycline, Oxytetracycline, Demeclocycline, Methacycline, Doxycycline, Minocycline, Rolitetracycline

Chloramphenicols

• MOA: Inhibits protein synthesis by binding to 50S subunit of bacterial ribosome.
• Broad spectrum
• Pharmacokinetic: Orally and IV; metabolized in liver; crosses placenta and blood-brain barrier.
• ADR: Bone marrow toxicity

Other Antibiotics (Types/Examples)

• Novobiocin Sodium
• Quinupristin/Dalfopristin (Synercid)
• Mupirocin (Bactroban)
• Linezolid (Zyvox)

Agents Affecting Bacterial DNA

• Quinolones (Nalidixic acid, Cinoxacin, Norfloxacin, Uritracin, Enoxacin, Ciprofloxacin, Ofloxacin, Lomefloxacin, Sparfloxacin)

This quiz explores antibiotics and their therapeutic classifications, mechanisms of action, and historical context. You will learn about various anti-infective agents, their characteristics, and the significance of antibiotics in modern medicine. Join us to test your knowledge on these vital substances that combat infections.