1. Overview of Antimicrobials
Dr W.D. Colby
Microbiology & Immunology

2. Classes of Antimicrobials
ß-lactams
Aminoglycosides
Extended macrolide family
Glycopeptides
Quinolones
Tetracyclines
Miscellaneous

3. ß-lactams
Inhibit cell wall synthesis by blocking peptidoglycan cross linking enzymes (PBPs)
Penicillins
Cephalosporins
Cephamycins
Carbapenems (thienamycins)
Monobactams

4. Penicillins Natural Aminopenicillins
Penicillinase-resistant semisynthetic penicillins
Antipseudomonal penicillins

5. Cephalosporins 1st generation 2nd generation 3rd generation
4th generation

6. Carbapenems Very broad spectrum ß-lactamase resistant
Imipenem/cilastatin
Meropenem

7. The Extended Macrolide Family
Bind to 50 S ribosomal subunit and inhibit protein synthesis
Macrolides
Azalides (azithromycin)
Ketolides (telithromycin)
Oxazolidinones (linezolid)
Quinupristin/dalfopristin
Clindamycin

8. Tetracyclines
Bind to 30 S ribosomal subunit and inhibit protein synthesis
Tetracycline
Doxycycline
Minocycline

9. Aminoglycosides Drugs of fear: ototoxic, vestibulotoxic, nephrotoxic
Bind to 30 S ribosomal unit
Gentamicin
Tobramycin
Amikacin

10. Glycopeptides
Inhibit synthesis of cell wall phospholipids and peptidoglycan polymerization
Effective against Gram positives
Vancomycin
Teichoplanin

11. Quinolones Bind to DNA gyrase and topoisomerase II 1st generation
2nd generation
3rd generation
4th generation

12. Evolution of Quinolones
Increasing activity vs
Gram +ve,
atypicals
and
anaerobes
Moxifloxacin is a new generation quinolone. Early quinolones had excellent gram-ve coverage, but little gram+ve, atypical or anaerobic coverage. As the quinolones evolved, the gram+ve coverage, atypical and anaerobic coverage increased, while maintaining gram-ve coverage. Unfortunately the newer generation quinolones are less active against Pseudomonas spp as Cipro.
Moxifloxacin has comparable gram-ve coverage to Cipro and Levo, with superior Gram+ve coverage. Moxifloxacin also has activity against all of the common atypical respiratory pathogens.

13. Miscellaneous
Co-trimoxazole
Metronidazole
Fusidic acid