BIOL4823 Antibiotics

nalidixic acid

1st gen quinolone 

used to treat UTI

G-

narrow spectrum

ciprofloxacin

F derivative of nalidixic acid

F makes compound more soluble

fluoroquinolone

G- and G+

rifampin

used to treat TB

can enter phagocytes

chloramphenicol

broad spectrum

can enter phagocytes

binds to 50s (prevents protein elongation)

fluoroquinolones

broad spectrum

2nd gen quinolones

G- and G+

inhibit DNA gyrase

bactracin

interferes with dephosphorylation and recycling of bactoprenol

topical only

inhibits cell wall synthesis

vancomycin

glycoprotein

binds to PG precursors

narrow spectrum

G+

methicillin

semisynthetic penicillin

b-lactamase resistance

narrow spectrum

G+

no longer produced

oxacillin

semisynthetic penicillin

b-lactamase resistant

narrow spectrum

G+

ampicillin

semisynthetic penicillin

b-lactamase resistant

broad spectrum

G- and G+

carbenicillin

semisynthetic penicillin

b-lactamase sensitive

ineffective orally

broad spectrum

very effective for G-

penicillin G

b-lactamase sensitive

narrow spectrum

G+

binds PBP

aminoglycosides

broad spectrum

G-

bind to 30S subunit so 50S cannot bind

toxic

last resort

tetracyclines

prevent tRNA from binding in 30S subunit

easy to add derivatives

low toxicity

G+ and G-

macrolides

narrow spectrum

(broader than penicillin)

binds to 50S preventing protein elongation

G+ and G-

erythromycin

binds to 50S

used when penicillin allergies

G+ and G-

clindamycin

aerobic G+

G-

binds to 50S

quinolones

interacts with DNA gyrase

can penetrate macrophages

G+ and G-

broad spectrum

metronidazole

requires activation (flavodoxin and ferrodoxin)

interferes with DNA synthesis by making breaks in DNA

narrow spectrum

anaerobic bacteria

G+ or G-

azithromycin (macrolide)

binds to 50S ribosomal subunit

broad spectrum

G+ and G-

2nd and 3rd gen cephalosporins

broad spectrum

G+ (mostly) and G-

binds to PBP