Antibiotics Flashcards
Penicillin MOA
Block transpeptidation by beta lactam ring binding penicilin binding proteins
ampicillin drug class
penicillin
good to treat gram-negative bacteria
methicillin drug class
penicillin
good for treating penicillin resistant Staph aureus
list 2 anti-pseudomona penicillins
carbenicillin
piperacillin
these are able to reach in pseudomonas tight pores
penicillin structure
beta lactam ring and thiazolidine ring
cephalosporin structure
beta lactam ring and dihydrothizine ring
cefazolin drug class
cephalosporin
cefotaxime drug class
cephalosporin
cefpodoxime drug class
cephalosporin
cephalosporins vs penicillins
cephalosporins are less susceptible to beta lactamases
carbapenems structure
beta lactam ring
carbapenems vs penicillins and cephalosporins
carbapenems are more resistant to beta lactamases and should be used as a last resort
active against broad spectrum
monobactams structure
monocyclic beta lactam
aztreonam drug class
monobactam
monobactams vs other beta lactams
resistant to most beta lactamases
active against many gram negative bacteria
vancomycin drug class
glycopeptide
teicoplnin drug class
glycopeptide
glycopeptide MOA
inhibits transpeptidation by binding NAG-NAM
weakly inhibit transfer of NAG-NAM disaccharide to peptidoglycan chains (transglycosylation)
use of glycopeptides
last resort for MRSA and antibiotic resistant strains of E. faecalis, S. pneumoniae, and S. epidermidis
broad spectrum for gram positives but not gram negatives since it is a large molecule (hard to cross gram -)
bacitracin MOA
binds undecaprenyl pyrophospate –> no recycling –> no NAG-NAM –> no peptidoglycan
bacitracin administration
topical (large so cannot be absorbed)
often combined with neomycin and polymyxin B
polymyxin B and E MOA
destabilize bacterial cell membranes by binding as detergents –> leakage
polymyxins B and E use
topical (significant toxicity)
active against most gram negatives and pseudomonas
Sulfamethoxazle drug class
sulfonamide
sulfonamide MOA
PABA analog
competitively inhibits synthesis of dihydrofolic acid (precursor for tetrahydrofolic acid: required for DNA synthesis)
thus, blocks bacterial DNA synthesis
trimethoprim (antifolate) MOA
DHF analog
competitively inhibits synthesis of tetrahydropholic acid which is required for bacterial DNA synthesis
fluoroquinolone MOA
bind/inhibit gyrase –> block DNA synthesis
ciprofloxacin drug class
fluoroquinolone
levofloxacin drug class
fluoroqinolones
fluoroquinolone use
broad spectrum
useful against pseudomonas auruginosa
Rifampin MOA
binds RNA polymerase –> inhibits protein synthesis
rifampin use
commonly used to trat mycobacterium tuberculosis
bacteria easily becomes resistant so often used in combo
macrolides/ketolides MOA
blocks peptide exit tunnel of 50S ribosomal subunit –> blocks protein synthesis
macrolide/ketolide use
broad spectrum
widely used resistance is common
erythromycin drug class
macrolide
telithromycin drug class
macrolide/ketolide
puromycin-like MOA
bind A-site of 50S subunit–> block tRNA access –> inhibit protein synthesis
clindamycin drug class
puromycin-like
clindamycin use
anaerobic bacteria
linezolid drug class
puromycin-like
linezolid use
MRSA, VRE, and penicillin resistant strep pneumoniae
tetracyclines/glycyclines MOA
binds A-site of 30S subunit (blocks tRNA access) –> inhibits protein synth
tigecycline drug class
tetracycline/glycyclines
aminoglycoside MOA
interfere with 30S ribosome subunit A site causing frequent mispairing –> synthesis of faulty proteins –> bactericidal
streptogramins MOA
block peptide exit tunnel of 50S ribosomal subunit streptogramin A (quinupristin) and B (dalfopristin) are bacteriostatic on their own but if used together they are bactericidal
streptogramins use
MRSA and most gram positives
which 2 drug classes that imhibit protein synthesis are bactericidal
aminoglycosides and streptogramins (when both A and B are used)
quinupristin drug class
streptogramin A
dalfopristin drug class
streptogramin B
Oxazolidimones MOA
Bind to 50s ribosome subunit to block protein synthesis
Fluoroquinolones: cidal or static?
Cidal
Block DNA gyrase
Metronidazole MOA
Block DNA gyrase
Metronidazole: static or cidal?
Cidal
Blocks DNA gyrase
Imipenem drug class
Carbapenems
Meopenem drug class
Carbapenem
Endopenem drug class
Carbapenem
When is use of bactericidal antibiotic use indicated?
Invassive infection: endocarditis and meningitis
List cidal antibiotics (7) used to treat endocarditis and meningitis
Beta lactams Fluoroquinolones Vancomycin Daptomycin Aminoglycosides Rifampin Metronidazole
What indicates use of bacteriostatic antibiotic drug use
Non invassive infections such as skin infections
Chloramphenicol: static or cidal?
Static except cidal for:
H. Influenzae
S. Pneumoniae
N. Meningitides
Linezolid: static or cidal?
Cidal against most strep
Static against MRSA and VRE
Trimethoprim-sulfamethoxazole (Bactrim) use against MRSA?
It is rapidly cidal against MRSA in vitro but not a lot of data on it so not a drug of choice
What is drug of choice for skin infections due to strep
Penicillins
No strep resistant to penicillins
What is not covered by penicillins
S.aureus
Gram negatives
Bacteroides
What is oxacillin’s coverage?
Gram positives, including S. Aureus
When treating intra-abdominal infections, what species are important to cover?
Gram negatives and anaerobes
What penicillin/beta lactamase inhibitor combo covers pseudomona
Piperacillin/tazobactam
What carbapenems cover pseudomona
Meropenem and imipenem
What is the contraindication of meropenem and imipenem use
It lowers the seizure threshold so not indicated for use in patients susceptible to seizures
How does 1st generation cephalosporins differ from other generations
Covers all gram positives including staph aureus
Ceftriaxone drug class and coverage
3rd generation cephalosporin
Covers all gram positives except s.aureus
Covers all gram negatives including pseudomonas
Ceftaroline drug class and coverage
Extended spectrum cephalosporin
Good for MRSA
Does not cover anaerobic or bacteroides or pseudomona
In penecillin allergies what two drug options can be used for pseudomona coverage
Azteronam
Aminoglycosides
What are the side effects of aminoglycosides
Stay in system a long time following administration which causes a threat of causes:
Nephrotoxicity: reversible
Ototoxicity: non reversible
Fluoroquinolone coverage
All aerobic gram neatives including pseudomona
Gram positives except s. Aureus
Ciprofloxacin drug class
Fluoroquinolone
Levofloxacin drug class
Fluoroquinolones
What are some side effects of fluoroquinolones
Can cause tendon rupture (especially weight bearing tendons such as achilles) Decreased mental status in elderly Prolonged Q-T syndrome C. Diff. (Vitamins can decrease its absorption)
What two fluoroquinolones are good for atypical organism use such as mycoplasma and legionella
Levoflaxicin and moxifloxacin
When treating mouth infections, what coverage is important
Strep and oral anaerobes
Clindamycin coverage
Good for above the diaphragm
Gram positive and anaerobe coverage including s. Aureus and MRSA but can induce MRSA resistance
Metronidazole coverage
Anaerobes
Good for below the diaphragm (G.I. And G.U.)
(Patients cannot drink alcohol)
Side effects of tetracyclines
Nausea/vomitting
Pill-induced esophaitis
Tetragenic (dont use in prenancy)
Photosensitivity
Doxyccline uses
Lyme disease Malaria prophylaxis Mycoplasma chlamydia MRSA infections Acne
Bactrim (TMP-SMX; sulfa drug) sideeffects
Skin rash
Contraindicatedin pregnancy
What are treatment obstions for initial episoides of non severe C. Diff
Oral vancomycin
FDX
What treatment is indicated in fulminant C. Diff. Infections
IV metronidazole (Fulminant= sick)
Daptomycin use
MRSA and VRE