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How do B-lactams work?

Blocks transpeptidase cross-linking of peptidoglycan in cell wall (weakened cell wall --> osmotic lysis)

Note: these are D-ala-D-ala analogs, thus blocking transpeptidase


Which drugs are B-lactams?

Penicillin, amox/ampicillin, cephalosporins, carbapenems, monobactams


How do bacitracin and vancomycin work?

Similar to B-lactams, but they block peptidoglycan synthesis (as opposed to blocking the cross-linking)

Mechanism: bind D-ala D-ala portion of cell wall precursors (pay back 2 D-alas for van-dalizing)


Protein synthesis inhibitors (buy AT 30, CCEL at 50)

30S inhibitors: Aminoglycosides = irreversible (genta, neomycin, amikacin, tobra, strepto) and Tetracyclines = static (tetra, doxy, mino

)50S inhibitors: Chloramphenicol, Clindamycin, Erythromycin (macrolides, azithro, clarithro), Linezolid


Aminoglycosides special things to know (side effects, uptake)

Side effects: nephro, ototoxicity, teratogen

Requires O2 for uptake, therefore can't use for anaerobes (Nocardia, Pseudomonas, myco TB)


Tetracyclines things to know

Doxy is used in renal failure pts

Don't give with divalent cations (Fe, Ca, Mg), they decrease absorption of the drug


Anaerobic infection tx

Above diaphragm: clindamycin (aspiration pneumo, lung abscesses, oral infxns)

Below diaphragm: metronidazole


Macrolides special factsside effects (MACRO)

Bind 23S subunit of 50S, block translocation

Motility issues
Cholestatic hepatitis


Folate synthesis inhibitors (Bactrim)

Trimethoprim - inhibit DHF reductase, TMP - treats marrow poorly (lots of -penias)

Sulfonamide - metabolites inhibit dihydropteroate synthase, watch out in G6PDH, can displace warfarin


Fluoroquinolones (levofloxacin, cipro, xacin)

inhibit DNA gyrase and topoisomerase IV

- hurt attachments to your bones! tendon problems in elderly and steroid pts



forms toxic free radicals in the bacterial cell wall

disulfiram-like with alcohol

metallic taste


Anti-mycobacterial (red body fluids, B6, optic neuropathy)

R: rifampin (4 R's = RNA pol inhibitor, Ramps up p-450, Red/orange urine, Rapid resistance alone

)I: isoniazid = decreased mycolic acid (cell wall), requires bacterial activation, used as solo ppx, give with B6 (INH hurt Neuron and Hepatos)

P: pyrazinamide

E: decreased cell wall polymerization, optic neuropathy (color blindness)!



Amphotericin B/Nystatin - forms pores by binding ergosterol

Flucytosine - used with Ampho, inhibit DNA/RNA synth

Azoles - inhibit p450, which makes ergosterol

Terbanifine - inhibit squalene epoxidase


Chloroquine resistance mech

Blocks detox of heme in hemozoin (heme is toxic to malaria)

resistance arises due to membrane pump that decreases [drug]i


Antiviral therapy

release of progeny virus
nucleic acid synthesis
protein synthesis

release of progeny - oseltamivir (inhibit influenza neuraminidase)

nucleic acid synthesis - guanosine analogs, inhibit viral DNA polymerase by chain termination (acyclovir: HSV, VZV) (ganciclovir: CMV) (last line: foscarnet: binds to polymerase)

protein synthesis - IFN-a, -B (MS), -y (CGD)


HIV medsProtease inhibitorsNRTIs (nucleoside reverse transcriptase inhibitor)NNRTIsintegrase inhibitorfusion inhibitor

HAART (3 drugs total)
2 NRTIs + NNRTI/protease inhib/integrase inhib

Navir = protease inhib (prevents HIV-1 protease from cleaving mRNA), don't give with rifampin (induces accel p450 metab!)

Vudine = nucleosides (cause bone marrow suppression, give G-CSF or EPO)


Hep C therapy

ribavirin - inhibit synthesis of guanine nucleotides (also used in RSV)

simeprevir - HCV protease inhibitor

sofosbuvir - inhibit HCV RNA-depndent RNA pol


M. tuberculosis virulence

Cord factor - in virulent strains, inhibit macrophage maturation, induces release of TNF-a (forms serpentine cords)

Sulfatides - inhibit phagolysosomal fusion


Resistance mechanisms

Decreased uptake - fluoroquinolones, aminoglycosides

Altered binding proteins/target - penicillins, sulfonamides, rifampin