24 terms

Quinolones, Macrolides, Vanc, Bacitracin, Clinda, Metro, and Polymyxins

Vancomycin: indications
only serious g(+) infections--MRSA, staph meningitis, C.diff
Vancomycin: mechanism and side effects (four)
similar to pens--inhibits peptidoglycan construction-->bactericidal

side effects: nephrotoxic, ototoxic, thrombophlebitis, "red man syndrome"
Bacitracin: indications and route of admin
gram (+) cocci eye and skin infections-->topical admin
Bacitracin: mechanism
similar to pens; interferes with regeneration of lipid carriers in peptidoglycan synthesis by blocking dephosphorylation
3 members of quinolone family
ciprofloxacin, norfloxacin, and ofloxacin
Quinolones: mechanism, route of admin
inhibits DNA gyrase (topoisomerase II)-->bactericidal
given PO
Quinolones: side effects (two) and contraindications (what type of pts)
side effects: n/v/d, can have suprainfections with streptococci and candida
Contraindicated in pts < 18 yrs and > 60 yrs for cartilage damage (tendinitis and tendon rupture); also in preg and nursing mothers
Quinolones: 2 mechanisms for drug resistance
1. gyrase mutation
2. decreased permeability of drug through porins
Quinolones: 8 indications
1. UTI by multi-drug resistant bacteria
2. gastroenteritis (by shigella, salmonella, E.coli, helicobacter)
3. osteomyelitis and soft tissue infections (not routine)
4. intraabdominal and respiratory tract infections (not routine)
5. gonococcal infections
6. chlamydia
7. prophylaxis for traveler's diarrhea
8. pseudomonas
Which quinolone is particularly anti-pneumoncoccal?
ofloxacin--has closely related levofloxacin and moxifloxacin which are also "respiratory" quinolones
Macrolides: 4 members
erythromycin, azithromycin, clarithromycin, and spectinomycin
Macrolides: mechanism
binds to 50S ribosome to inhibit aminoacyl translocation-->bacteriostatic
Macrolides: drug resistance
plasmid-mediated gene encodes alternate protein on 50S ribosome
Erythromycin: indications (ten)
1. DOC in community-acquired pneumonia (includes S. pneumoniae, Legionella, M. pneumoniae)
2. Treponema if pens allergy
3. Ureaplasma
4. Chlamydia (esp during preg)
5. Helicobacter
6. Listeria
7. Neisseria
8. Bordetella pertussis
9. Campylobacter
10. Gram pos: Pneumococci, Streptococci, Staphylococci, C. diphtheriae (eliminate carrier state)

Similar spectrum as pen G
Azithromycin: indications (two)
1. chlamydia
2. H. influenzae
Clarithromycin: indications (two)
1. H. pylori (in combo with amoxicillin + PPI)
2. H. influenzae
Spectinomycin: indications
GU gonorrhea if pens allergy or if gonorrhea is pens-resistant
Clindamycin: indications
B. fragilis infections, also Strep, Staph, and pneumococcal infx
Clindamycin: mechanism and route of admin
inhibits protein synthesis
Clindamycin: side-effects (two)
1. suprainfection by C. difficile
2. hepatotoxicity
Metronidazole: indications (three)
Bacteriodes, Clostridia, and Pseudomembranous colitis
Metronidazole: mechanism and route of admin
inhibits DNA synthesis-->bactericidal
oral; IV available
Metronidazole: side effects (two)
1. minor GI and CNS disturbances
2. Interferes with EtOH metabolism--disulfram-like effect-->decreases activity of aldehyde dehydrogenase, so aldehyde toxicity
Polymyxins: indications and mechanism
topical for eye and ear with bacitracin or neomycin
binds to phosphatidyl ethanolamine--detergent-like activity