antibiotics Flashcards
clavulanic acid and sulbactam
B lactamase inhibitors. can combine with b lactam antibiotics to resist bacterial B lactamase.
What are the four groups of B-lactam antibiotics?
1) Penicillin
2) Cephalosporins
3) Carbapenems
4) Monobaactams
Which B lactam undergoes active secretion in the kindey, causing high concentrations of unchanged drug in the urine?
Penicillins
Don’t use penicillin orally in which species?
Ruminants, horses, guinea pigs, and chinchillas
SO YOU CAN use it orally in dogs, cats, pigs, etc
Penicillin G
- natural NARROW spectrum (lg animal)
- USE PARENTERALLY
1) Penicillin G K/Na = IV or IM
2) Penicillin G Procaine = IM only NOT IV - use in gram pos/neg cocci, clostridium, lepto
Ab drugs that are nephrotoxic (damage renal tubular epithelial cells) (3)
1) aminoglycoside
2) polymixins
3) tetracyclines
(TAP) tap into the tubes
(bacitracin has potential)
these same drugs interfere with neuromuscular blockade (esp in combo with anesthetics)
AB drugs that are nephrotoxic (damage the collecting ducts)
sulfonamides (crystalluria)
AB that are Hepatotoxic (3)
1) tetracyclines
2) erythromycin
3) TMPS
tetracyclines damage both liver and kidney ! TET
ototoxicity can be a side effet in which group?
aminoglycosides
which can lead to CNS excitment, causing it to only be used IM in large animals most commonly?
Penicillin G
cartilage damage in growing dogs
floranquinalones
bone marrow toxicity ( anemia and leukopenia) (3)
1) chloramphenicaol
2) sulfonamides
3) trimithoprim
GI upset (3)
1) ampicillin, linocmycin, clindamycin
CAL me if you have GI upset
Natural penicillin
Penicillin G-> G+ aerobes/anerobes
Semisynthetic penicillin
amoxicillin/ampicillin-> moreG-, slightly less G+
B lactamase resistant penicillin
Cloxacillin-> staph/strep B lactamases
-im gonna CLOX those B lactamase resistant bacteria
Anti- pseudomonas penicillin
Ticarcillin-> imma “ tic cara that pseudomonas”
which antibiotic is not supposed to mixed with B lactams ABs INVITRO?
aminoglycosides-> they have a synergsitic efffect INVIVO
Amoxicillin/ampicillin
seminsynthetic with broader range than PenG
- use in small animals, equine, and MASTITIS in cattle
- ampicillin -> is amped to get to work give it parenterally
- amoxicillin -> ORALLY
Amoxicillin-Clavulanic acid (clavamox)
C acid binds to Blactamase to increase afficacy of amoxicillin
-only use if B lactamase (resiistance) is suspected or confirmed!)
Cloxacillin
B lactamase stable penicillin
hes gonna clox that resisitant bacteria
Ticarcillin
pseudomonas fighting !
Cephalexin
1st generation
FIRST LINE ANTIOBIOTIC in small animals
ORALLY
can dose higher for gram neg sometimes (recall first gen more Gram pos than neg)
cefazolin
first generation
same spectrum as cephalexin but PARENTERAL use NOT ORAL
use in small animals and horses
*used prophylactically in surger (as you ‘zol’ into surgery)
cephapirin
first generation
similar spectrum as cephalexin
MASTITS in cattle -> intramammary infusion
“whats hapirin” with that udder ?!”
cefoxitin
second generation
ANAEROBES
given IV to treat serious infections
ceftiofur
third generation
LG animal - FOOT ROT, MASTITIS, RESP dz
‘Fur’ = Foot root, Udder inflammation, Resp dz
cefovecin
third generation 99% protein boud -> REALLY LONG duration of action dosed q7-14 days injectable DOGS: PYODERMA due to staph and strep CATS: pasteurella
cefpodoxime
third generation
small animal GRAM NEG infection (third generation!! )
prodrug ester (cefpodoxime proxetil) converted to active after GI absorption
which of the b lactam ABS classes is lease prone to being affected by resistance ?
Carbapenems
about carbapenems
- less prone to resistance
- TREAT PSEUDOMONAS
- last resort for extendeded spectrum beta lactamase bacterial infxn
- LONGER PAE that other beta lactam ABs
- PARENTERAL ONLY!!!!(IV SQ)
- imipenem - IV infusion only
- meropenem -SUB Q
- DO CROSS THE BBB
- greater toxic potential than other B lactams
imipenem
uncommonly used in small animals for hihg resistant gram - bacteria
- DILUTE IV SLOW INFUSION - risk of seizures, phlebitis
- ALWAYS combo with CILASTIN to delay metabolism and reduce renal toxicity
meropenem
same indication as imipenem
CAN be used SUB Q
fewer side effects
Glycopeptide AB of vet interest
vancomycin
MoA of vancomycin
its a glycopeptide -> so it bnids to PEPTIDEoGLYCan ‘ends’ and prevents formation of long polymers needed to form the cell wall as stops corss linking. leads to structural instabolity and osmotic pressure susceptibilty(like B lactams)
T or F:
vancomycin is useful against both Gram pos and Gram neg bacteria like other cell wall synthesis inhibotrs (B lactams, Bacitracin, and polymixin B)
FALSE: Vancomycin (glycopeptide), bacitracin, and Polymixin B (cell membrane inhibition) are not able to act on both Vancomycin = GRAM POS ONLY Polymixin B = GRAM NEG ONLY Bacitracin = GRAM POS ONLY
Vancomycin
-last resort against MRSA in humans use carefully
-works on any gram pos
-b lactam resistant infxn
-not abosrbed orally! -> can be used to fight C. difficile in the GI tract
-USE IV ONLY
-does not cross the BBB (only cell wall synthesis AB that does are carbapenems)
-some synergy seen with aminoglycosides (UNLIKE B LACTAMS)
-BANNED IN FOOD PRODUCTION
-
can you use all of the cell wall synthesis ABs in food production?
VANCOMYCIN IS NOT PERMITTED TO BE USED IN FOOD ANIMALS
Bacitracin MoA
bind to isoprenyl pyrophosphate enzyme which transports building blocks to make polymer chains in the cell wall.
Bacitracin
GRAM POS ONLY
bacteriocidal or static
-NEPHROTOXIC -> so use orally or topically only
-complexed with zinc
-part of the ‘triple antibiotic’ ointment (Neosporin, polymixin B, bacitracin)
resisance not a problem despite being used in food production
Polymixin B MoA
ACTS ON THE CELL MEMBRANE (so gram Neg duh)
- acts as a CATIONIC DETERGENT to the phospholipid cell membrane and breaks it down (binds to LPSs endotoxin)
- cytoplasm leaks out-> rapid cell death
polymixin B
gram neg only
- including PSEUDOMONAS
- resisance aquired is rare
- MoA makes it viable to attack mammalian cells -> TOXIC-> only use topically
- using other than topical would lead to nephro and ototoxicity
- available as part of the triple antibiotics (with bacitracin and neomycin)
what should you be aware of about BNP ointments?
fatal anaphylactic resposes in cats has been reported
Cell wall synthesis drugs that DO treat pseduomonas
polymixin B
ticarcillin
carbapenems
MoA of tetracyclines
binds charged transfer RNA (which would normally bind to 30s ribosimal subunit nRNA complex)
Tetracycline binds T RNA
about tetracyclines
generally ORALLY abosorbe(except oxytetracycline)
large spectrum (gram pos and neg, spirochetes -> lepto and borrelia, rickettsila -> ehrlicia and anaplasma, mycoplasma, chlamidophila, anaerobes
-bacteriostatic
-GOOD PENETRATION IN HARD TO REACH TO REACH TISSUES (csf, bone, prostate)
-ANTAGONSITIC TO PENICILLINS
-YELLOWING OF TEETH in growing animals
-GI ISSUES-anoerxia (small animal), esophageal stricture (cats), superinfection in horses, bitter tasting
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