SEARCH RESULTS FOR: Vancomycin

Antibiotics Classes and Mechanisms

Antibiotics: Overview of classes and mechanisms of action Nucleic acid synthesis inhibitors Cell wall synthesis inhibitors Protein synthesis inhibitors Nitroimidazoles (e.g. metronidazole) Antibiotic is activated by bacterial pyruvate:ferredoxin oxidoreductase system (only active in anaerobic bacteria) Fluoroquinolones** (e.g. ciprofloxacin) Drug binds & inhibits bacterial DNA topoisomerases (enzymes that cut & re-ligate DNA to stabilize helix) β-lactam antibiotics Penicillins (e.g. amoxicillin) Cephalosporins (e.g cefazolin) Carbapenems (e.g meropenem) Drug binds & inhibits penicillin binding proteins (enzymes involved in peptidoglycan cross-linking & cell wall synthesis) β-lactam with β- lactamase inhibitor (e.g. amoxicillin- clavulanate) β-lactamase inhibitor irreversibly binds bacterial β-lactamases (enzymes that break β-lactam rings & contribute to β-lactam resistance) Glycopeptides (e.g. vancomycin) Drug binds to bacterial cell wall peptidoglycan precursors, interrupting cell wall synthesis Aminoglycosides (e.g. gentamicin) Drug irreversibly binds bacterial 30S ribosomal subunit Binding interferes with proofreading process in mRNA translation Macrolides (e.g. azithromycin) Lincosamides (e.g. clindamycin) Tetracyclines (e.g. doxycycline) Sulfonamides (e.g trimethoprim- sulfamethoxazole) Reactive nitrogen free radicals generated Single- & double- stranded DNA breaks form without re-ligation ↓ Bacterial cell wall cross-linkage Free radicals interact with and destroy bacterial DNA DNA fragments released into cell Autolysins weaken & lyse bacterial cell wall Author: Steven Quan Reviewers: Julia Fox, Emily J. Doucette, Brandon Christensen* *MD at time of publication Bactericidal (bacterial cell death) β-lactamases are unable to break β-lactam rings, allowing for β-lactam function Bacterial cell wall is incomplete & weakened Incorrect amino acids accepted into protein chain Bacteria undergoes lysis Nonfunctional proteins produced Metabolic pathway inhibitors Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Drug reversibly binds bacterial 50S ribosomal subunit Drug reversibly binds bacterial 30s ribosomal subunit Drug binds & inhibits bacterial dihydropteroate synthetases (enzymes involved in folate synthesis) Complications Binding physically inhibits addition of amino acids, preventing peptide elongation Binding inhibits tRNA from adding amino acids to protein chain Bacteria cannot produce folate (cofactor required for nucleotide synthesis) Protein synthesis not completed ↓ Nucleotide production Bacteriostatic (inhibition of bacterial growth & replication) **See corresponding Calgary Guide slide Published Sept 16, 2025 on www.thecalgaryguide.com

Vancomycin

Vancomycin: Mechanism of action and side effects Vancomycin Glycopeptide antibiotic that inhibits bacterial cell wall synthesis. Active against gram-positive organisms, such as Staphylococcus aureus (including MRSA), coagulase-negative Staphylococcus spp., Streptococcus spp., Enterococcus spp. (including E. faecium), & Clostridium difficile (when given orally). Often requires therapeutic drug monitoring due to risk of toxicity. Blocks cross-linking of peptidoglycan strands Drug binds to D-alanyl-D- alanine (D-Ala-D-Ala) terminal of peptidoglycan precursors Acquisition of van gene clusters (vanA/vanB) Transglycosylation & transpeptidation reactions are inhibited Target site changes from D-Ala-D-Ala to D-Ala-D-Lac or D-Ala-D-Ser Bacterial cell wall becomes osmotically unstable ↓ Binding affinity of drug to bacteria Bacterial cell lysis Development of vancomycin resistance Bacterial clearance on microbiological culture Legend: Primarily eliminated by glomerular filtration Presence of renal dysfunction impairs drug clearance ↑ Serum drug levels Oxidative stress & mitochondrial dysfunction of proximal tubular epithelium Direct proximal tubular cell injury Acute tubular necrosis** or acute interstitial nephritis ↓ Kidney function ↑ Serum creatinine & ↓ glomerular filtration rate (GFR) Prolonged therapy or prior exposure Rapid infusion, high dose or co- administration with anesthetics Possible direct damage to auditory branch of cranial nerve VIII (mechanism not well understood) Sensorineural hearing loss, tinnitus**, &/or balance disturbance Vancomycin- dependent antibodies are produced Antibodies bind to platelets &/or neutrophils Reversible cytopenia +/- bleeding Platelet &/or neutrophil destruction ↓ Platelets &/or ↓ neutrophils Activation of mast cells & basophils (non-IgE) Self-limited infusion reaction (not an allergy) Mast cell degranulation releases histamine & other vasoactive mediators Erythema of face, neck & torso ↓ Blood pressure Pruritus (itching) Author: Oleksandr Baran Reviewers: Trevor Low, Emily J. Doucette, Brandon Christensen* *MD at time of publication **See corresponding Calgary Guide slide Published Dec 7, 2025 on www.thecalgaryguide.com Pathophysiology Mechanism Pharmacologic Effects Side Effects