Anti-Microbial Agents Flashcards
Gram stained gram+ color
purple
Gram stained gram- color
pinkish
bacteriostatic agents…
prevent growth
bactericidal agents
kill
4 classes of antibiotics
- cell wall synthesis inhibitors
- protein synthesis inhibitors
- folic acid synthesis inhibitors
- DNA synthesis inhibitors
cell wall synthesis inhibitors
Beta-lactam antibiotics
cephalosporins
other drugs
protein synthesis inhibitors
Tetracyclines
macrolides
other drugs
folic acid synthesis inhibitors
sulfonamides
trimethoprim
DNA synthesis inhibitors
quinolones
principle of antibiotic therapy
harm the parasite, not the host
Penicillins are
beta-lactam antibiotics
Penicillins inhibit bacteria by
impeding cell wall synthesis
Penicillins are unstable
in acidic pH
Penicillin is the drug of choice for infections caused by
streptococcus meningococcus anthrax clostridium etc
Hypersensitivity to penicillin can lead to
anaphylactic shock
semi-synthetic penicillins
ampicillin
amoxicillin
methicillin
penicillins are administered
oral or IM - never IV!
penicillins are susceptible to destruction by
beta-lactamase (penicillase)
cephalosporins are similar to penicillins in what way(s)
chemically
mechanism of action
toxicity
Cephalosporins are _________ ___________ compared to penicillins
broader spectrum
Cephalosporin generations 1 & 2 are for
gram+
Cephalosporin generations 3 & 4 are for
gram- (cross BBB)
Side effects of antibiotics are more likely if you…
use multiple antibiotics together
Other beta lactams, beta-lactamase inhibitors and cell-wall synthesis inhibitors
clavulonic acid
carbapenems
vancomycin
bacitracin
How tetracycline works
accumulates inside bacterial cell & binds to ribosomes, impeding formation of new protein
Tetracyclines should be avoided for
young horses or pregnant mares
Tetracyclines can’t be ingested with
calcium
Tetracyclines work on
gram+, gram-, reckettsia, anaerobes, protozoa, etc. (broad spectrum)
Macrolides
erythromycin
clarithromycin
azythromycin
Macrolides can cause
diarrhea
light sensitivity
fever
Macrolides are not to be used in horses
over a year old
Macrolides are used in conjunction with _________ to treat _____________
Rimfampin
Rhodococcus equi pneumonia in foals
Other protein synthesis inhibitors
aminiglycosides streptomycin neomycin gentamicin amikacin trobramycin
They are used against ______ bacteria
enteric
Triple antibiotic ointment contains
bacitracin
neomycin
polymyxin b
protein synthesis inhibitors are extremely
ototoxic and nephrotoxic (ear, kidney)
sulfonamides (sulfas) reversibly block
folic acid synthesis
Sulfas are bacteri_______
-ostatic
bacteriostatic drugs stop
multiplication
PABA
para-aminobenzoic acid - some microorganisms require it to form folic acid - for nucleic acid synthesis
Trimethoprim is used in conjunction with
SMZ (sulfamethoxazole)
sulfa+trimethoprim =
bactericidal
Fluoroquinolones: floxacins are _________ _________
broad spectrum
floxacins are useful against
E coli, great for gram-, newer also good for gram+