Formatted_Prophylactic_Antimicrobial_Use.docx

### Antibiotic Classification and Mechanisms of Action 1. ### Antibiotic Classifications - ### Narrow-spectrum antibiotics: Effective against a limited range of species. - ### Broad-spectrum antibiotics: Effective against various microbes, preferred for urgent or emergent treatment....

### Antibiotic Classification and Mechanisms of Action 1. ### Antibiotic Classifications - ### Narrow-spectrum antibiotics: Effective against a limited range of species. - ### Broad-spectrum antibiotics: Effective against various microbes, preferred for urgent or emergent treatment. - ### Bacteriostatic agents: Inhibit bacterial growth. - ### Bactericidal agents: Directly kill bacteria. 2. ### Resistance to Antibiotics - ### Microbial causes of resistance: Selection pressure favors resistant organisms. - ### Broad-spectrum agents: Most likely to contribute to drug resistance. - ### Genetic basis of resistance: DNA mutations and microbial genome changes. ### ### Key Antibiotic Drug Classes and Prototypes 1. ### Penicillin Class - ### Amoxicillin (Moxatag) - ### Spectrum: Broad (Gram-positive & Gram-negative) - ### Uses: Pharyngitis, tonsillitis, otitis media, H. pylori, endocarditis prophylaxis with dental procedures. - ### Adverse Effects (AE): Increased risk of rash with allopurinol or mononucleosis. 2. ### Cephalosporin Class - ### Cephalexin (Keflex) - ### Spectrum: Broad, bactericidal, first-generation. - ### Uses: Staph and strep infections, surgical prophylaxis, bone and skin infections. - ### Contraindications (CI): Severe allergy to penicillin. - ### AE: Rash, diarrhea, rare C. difficile infection. 3. ### Carbapenem Class - ### Imipenem & Cilastatin (Primaxin) - ### Spectrum: Broad (Gram-positive & Gram-negative). - ### Uses: Mixed infections, bloodstream infections, bone and joint infections. - ### CI: Use with Valproate increases seizure risk. - ### AE: Superinfection risk; IV only. 4. ### Glycopeptide Class - ### Vancomycin (Vancocin) - ### Spectrum: Gram-positive bacteria only. - ### Uses: C. difficile, MRSA, penicillin-resistant pneumococci. - ### CI: Renal impairment, nephrotoxicity with aminoglycosides. - ### AE: Redman syndrome; IV (oral for C. difficile). 5. ### Tetracyclines - ### Example: Doxycycline - ### Spectrum: Bacteriostatic, second-line agents. - ### Uses: Acne, periodontal disease. - ### CI: Children under 8 (tooth discoloration), pregnancy, breastfeeding. 6. ### Macrolides - ### Erythromycin - ### Spectrum: Broad (Gram-positive & Gram-negative). - ### Uses: Diphtheria, H. pylori, pertussis, alternative for penicillin allergy. - ### CI: QT prolongation. - ### AE: GI symptoms (take with food). 7. ### Lincosamide - ### Clindamycin (Cleocin) - ### MOA: Inhibits protein synthesis. - ### Uses: Anaerobic infections, severe group A streptococcal infections, gas gangrene. - ### CI: Discontinue if C. difficile is diagnosed; AE: Colitis & C. difficile infection (black box warning). 8. ### Oxazolidinone Class - ### Linezolid (Zyvox) - ### Spectrum: Aerobic, Gram-positive bacteria. - ### Uses: VRE, hospital-associated pneumonia by S. aureus. - ### CI: MAOI use within 2 weeks; risk of serotonin syndrome with SSRIs. - ### AE: Optic and peripheral neuropathy with prolonged use. ### ### Special Use Cases 1. ### Sulfonamides - ### Trimethoprim/Sulfamethoxazole (Bactrim) - ### Spectrum: Broad, Gram-positive & Gram-negative. - ### Uses: UTIs, otitis media, pneumonia, E. coli, shigellosis. - ### CI: Nursing mothers, G6PD deficiency, folate deficiency. - ### AE: Renal impairment, rash. 2. ### Aminoglycosides - ### Gentamicin - ### Spectrum: Aerobic, Gram-negative bacilli. - ### Uses: Serious infections, E. coli, pseudomonas. - ### CI: Hearing problems, renal disease. - ### AE: Neurotoxicity, nephrotoxicity (black box warning). ###