Micro Drugs bacteria, virus

eesohbel's version from 2015-08-10 19:20

Penicillin Drugs

Question Answer
What is the mechanism of action of penicillin G, V?Binds penicillin-binding proteins (transpeptidases). Blocks transpeptidase cross-linking of peptidoglycan in cell wall. Activates autolytic enzymes
What is the clinical use of Penicillin G, V? Mostly used for gram positive organisms. Also gram negative cocci and spirocheters.
How does resistance develop to penicillin G, V? Pencillinase in bacteria cleaves B-lactam ring.
Mechanism of amoxicillin and ampicllin? Same as penicillin. WIder spectrum: penicllinase sensitive like penicillin
Clinical use of amoxicillin and ampicillin? grams +'s plus HHELPS (H. Flu, H. Pylori, E Coli, Listeria, Proteus, Salmonella, Shigella)
What is special about methicillin, nafcilllin, oxacillin?Only PENCILLIN TYPE THAT IS Penicillinase resistant because bulky R groups blocks access of B-lactamase to B-lactam ring. They are not active against MRSA however
What is the clinical use of piperacillin, tiracillin and carbenicillin? Pseudomonas and gram negative rods
What is the purpose of B-lactamase inhibitors?To protect the antibiotic from destruction by B-lactamase (penicillinase)
What happens if you give a patient amoxicillin with mono? Rash
Penicillins are structural analogs ofD-Ala-D-Ala
piper-tazogram negative rods


Question Answer
Mechanism of actionB lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinases.
What happens as you increase in generation of cephalosporinsyou increase gram - coverage and decrease gram + coverage
What are the first generation cephalosporinscefazolin and cephalexin
What bugs do first generation coverPEcK (Proteus, E. coli, Klebsiella)
What bugs do second generation coverHENS PECK (H. Flu, Enterobacter, Neisseria, Serratia, Proteus, E. coli, Klebsiella)
What are the second generation cephalosporinscefoxtin, cefaclor, cefuroxime
What are the third generation cephalosporinscerftriaxone, cefotaxime, ceftazidime
What bugs do third generation coverserious gram negative infections (ceftazidime has pseudo coverage). klebsiella pneumonia
What is the 4th generation cephalosporincefepime
What bugs do 4th generation cephalosporins covergram negative organisms increased activity against pseudomonas and gram positive organisms.
What is the 5th generation cephalosporincepftraloine- broad gram positive and gram negative, including MRSA; does NOT include pseudomonas
What bugs do cephalosporins not coverthey are LAME against (listeria, atypicals, MRSA and enterococci). Remember ceftaroline covers MRSA
A/E of cephalosporinsdisulfram like reactions, cross reactivitity with penicillins, increased nephrotoxicity of aminoglycosides
Mechanism of resistancechange in penicillin binding proteins and beta lactamases


Question Answer
Mechanism of action of carbapenemsimpinem is a broad spectrum, B-lactamse resistant carbapenem. Always administered with cilastin (inhibitor of renal dehydropeptidase I) to decrease inactivation of drug in renal tubules
What is the clinical use of carbapenemsgram positive cocci, gram negative rods and pseudomonas.
Toxicity of carbapenemsSignificant side effects limit to life threatening infections. CNS toxicity at high plasma levels
What is the mechanism of action of monobactams (aztreonam)less susceptible to B-lactamases. Prevents peptidoglycan cross linking by binding to penicillin binding protein 3. Synergistic with aminoglycosides
If someone has a penicillin allergy will they be allergic to aztreonamNO. There is no cross allergenicity with penicillins.
Clinical use of aztreonamgram negative rods only (including pseudomonas). No activity against gram-positive or anaerobes.
Mechanism of action of vancomycininhibits cell peptidoglycan formation by binding D-ala D-ala Portions of cell wall precursors. Not susceptible to B-lactamases.
Clinical use of vancomycingram positive bugs only
Toxicity of VancomycinRed man syndrome and remember NOT (Nephrotoxicity, Ototoxicity, Thrombophlebitis)
How can one prevent red man syndromeslow down infusion of vancomyci and pretreat with antihistamines
Mechanism of Resistance against VancomycinOccurs in bacteria via amino acid modification of D-ala D-ala to D-ala D-lac
What new carbapenem has less risk of seizuresmeropenem and is stable to dehydropeptidase I so do not need to administer cilastain like with imipenem
Do you need your kidneys to work to tolerate monobactamsNO!

Protein Synthesis Inhibitors

Question Answer
Mnemonic for the Protein Synthesis InhibitorsBuy AT 30, CCELL at 50. (aminoglycosides, tetracyclines) (chloramphenicol, clindamycin, erythryomycin (macrolides), linezolid, lincomycin)
Mechanism of action of aminoglycosidesirreversible inhibition of initiation complex through binding of 30S complex. Can cause misreading of MRNA. Requires O2 for uptake ineffective against anaerobes.
Clinical use of aminoglycosidessevere gram negative rods infections
Toxicity of aminoglycosidesNOT (nephrotoxicity, NMJ blockage, Ototoxicity, Teratogen) don't confuse with NOT of vancomycin
What are the aminoglycosidesgentamicin, neomycin, amikacin, tobramycin, streptomycin
How do bugs become resistant to aminoglycosidesBacterial transferase enzymes inactivate the drug by acetylation, phosphorylation or adenylation. Mutation of genes that encode ribosomal proteins nencause tehy modify the ribosomal binding sites for drugs.
MOA of tetracyclinesBind to 30S and prevent attachment of aminoacyl-tRNA; limited CNS penetration.
Do not take tetracyclines withmilk or antacids because divalent cations inhibit drug's absorption in the gut
Clinical use of tetracyclinesBorrelia, M. Pneumoniae, Rickettsia, Chlamydia, Acne
Toxicity of tetracyclinesDiscoloration of teeth and inhibition of bone growth in children and photosensitivity
Mechanism of resistance of against tetracyclinesdecreased uptake or increased efflux out of bacterial cells by plasmid encoded transport pumps
Chloramphenicol toxicitygray baby syndrome in premature infants because the lack liver UDP glucuronyl transferase. Can give phenobarbital. Also causes aplastic anemia
Clindamycin clinical useanaerobic infections above the diaphragm versus metro anaerobic infections below the diaphragm
Toxicity of clindamycinPseudomembranous collitis
LinezolidMechanism of action specifically binds to 23S portion of 50S subunit. Prevents formation of initiation complex
Linezolid clinical usegram positive species including MRSA and VRE
Linezolid toxserotonin snydrome, peripheral neuropathy
MOA of macrolidesinhibits translocation binds to 23S subunit of 50s subunit
Clinical use of macrolidesPUS (atypical Pneumonia, URI, STD)
Toxicity of macrolidesMACRO (gi Motlity, Arrhthymia, acute Cholestatic hepatisis, Rash, eOsinophilia)
Mechanism of resistance against macrolidesmethylation of 23S rRNA binding site


Question Answer
inhibits formation of initation complexaminoglycosides and linezolid
inhibits amino acid incorporation by blocking the attachemnt of aminoacyl tRNA to acceptor sitetetracyclines
inhibits formation of peptide bond by inhibiting activity of peptidyltransferasechloramphenicol
inhibits translocation of peptidyl RNA from acceptor to donor sitemacrolides and clindamycin

THF inhibitor pathway

Question Answer
MOA of trimpethopriminhibits bacterial dihydrofolate reductase
Toxicity of trimpethoprimmegaloblastic anemia
What drugs block dihydrofolate reductasetrimethoprim, methotrexate and primethamine
Mechanism of action of sulfonamidesinhibit folate synthesis. Inhibit dihydropteroate synthase.
Toxicity of sulfonamidesHemolysis if G6PD deficient, kernicterus, SJS, phototoxicity
What are the sulfa drugsSulfa Pills Frequently Cause Terrible Acute Symptoms (Sulfalazine, Probenecid, Furosemide, Celecoxib, Thiazides, Acetazolamide, Sulfonyureas)


Question Answer
Mechanism of fluroquinolonesinhibit prokaryotic enzyme topoisomerase II and topoisomerase IV
Toxicity of fluroquinolonesMay cause cartilage damage in children less than 18. May cause tendonitis in those over 60. Prolong QT interval
Mechanism of resistance against fluroquinoloneschromosome-encoded mutation in DNA gyrase, plasmid-mediated resistance, efflux pumps
Clinical use of daptomycinS. Aureus Skin infections
Toxicity of daptomycinmyopathy, rhabdomyolysis
Mechanism of Action of MetroForms toxic free radical metabolites in the bacterial cell that damage DNA.
Clinical use of metroGET GAP on the Metro (Giardia, Entamoeba, Trichomonas, Gardenerella, Anaerobes, h.Pylori)
Toxicity of metrodisulfram-like reaction with alcohol


Question Answer
High risk for endocarditis and undergoing surgical or dental proceduresamoxicillin, cephalexin, amoxicillin
exposure to gonorrheaceftraxione
history of recurrent UTISTMP-SMX, nitrofurantoin, amoxicillin, cephalexin
Exposure meningococcal infectionceftriaxone or ciprofloxacin or rifampin
Prevention gonococcal conjunctivitis in newbornerythromycin ointment
Prevention of postsurgical infection due to S. aureuscefazolin
prophylaxis of strep pharyngitis in child with prior rheumatic feverpenicillin G or oral penicillin V
exposure syphillispenicillin G
H. Flurifampin
pregnant women w GBSampicllin
MAI CD4 count less than 50azithromycin

Antimycobacterial drugs

Question Answer
IsoniazidDecreases synthesis of mycolic acids
Use: prophylaxis against TB (only drug used alone for TB ppx)
Neuro (prevented with B6), hepatotoxic, lupus
Inhibits P450
RifampinInhibits DNA-dependent RNA polymerase
Use: TB, leprosy, H. influenza, meningococcal prophlaysis
Tox: Revs up P-450, red/orange body fluids
Works within macrophage phagolysosomes - requires acidic environment
Tox: hyperuricemia, hepatotoxic
Ethambutol↓ carbohydrate polymerizaction of mycobacterium cell wall by blocking arabinosyltransferase
Tox: optic neuropathy (red-green color blindness)
streptomycinaminoglycoside that inhibits protein synthesis by inactivating the 30s ribosomal subunit.
resistance to isonazidnon-expression of catalse peroxidase enzyme or genetic modification of isoniazid binding site on mycolic acid synthesis enzymes
resistance to rifampinstructural alteration of enzymes involved in RNA synthesis
resistance to streptomycininhibits protein synthesis by inactivating 30S ribosomal unit

General antivirals

Question Answer
Zanamivir, oseltamivir mechinhibit influenza neuraminidase - decreasing the release of progeny virus
Zanamivir, oseltamivir clinical usetx and prevention of both influenza A and B
Ribavarin mechInhibits synthesis of guanine nucleotides by competitively inhibiting IMP dehydrogenase
Ribavarin clinical useRSV, chronic hepatitis C
Ribarvirin toxhemolytic anemia. Severe teratogen
Acyclovir mechMonophophorylated by HSV/VZV thymidine kinase
Guanosine analog
Preferentially inhibits viral DNA polymerase by chain termination
Acyclovir clinical useHSV & VZV + weak activity against EBV
Valacyclovirprodrug of acyclovir w better oral bioavailability
Famciclovirrelated to acyclovir
for herpes zoster
Acyclovir mechanism of resistanceMutated viral thymidine kinase
Ganciclovir mech5'-monophosphate formed by a CMV viral kinase
Guanosine analog
Preferentially inhibits viral DNA polymerase by chain termination
Ganciclovir clinical useCMV, esp in immunocompromised
Progdrug, valganciclovir, has better oral bioavailability
Ganciclovir toxLeukopenia
renal tox
more toxic to host enzymes than acyclovir
Ganciclovir mech of resistancemutated viral kinase
Foscarnet mechViral DNA\RNA polymerase inhibitor and HIV transcripitase inhibitor that binds to the pyrophosphate-binding site of the enzyme
Does not require activation by viral kinase
Foscarnet clinical useCMV retinitis in immunocompromised patients when ganciclovir fails
acyclovir-resistant HSV
Foscarnet toxnephrotoxic. Lead to symptomatic hypocalcemia and hypomagensia. Can promote seizures
Cidofovir mechpreferentially inhibits viral DNA polymerase
does not require phosphorylation by viral kinase
Cidofovir clinical useCMV retinitis in immunocompromised patients when ganciclovir fails
acyclovir-resistant HSV
Cidofovir toxicitynephrotoxic - coadminister with probenecid and IV saline to reduce toxicity
HSV-1 latent intrigeminal ganglia
HSV-2 latent insacral ganglia
VZV latent indorsal root ganglia

chronic Hep C therapy

Question Answer
ribavirininhibits synthesis of guanine nucleotides by competitively inhibiting inosine monophosphate dehydrogenase
simprevirHCV protease inhibitor
sofosbuvirinhibits HCV RNA dependent RNA polymerase acting as a chain terminator

Drugs to avoid in pregnancy

Question Answer
flurocartilage damage
tetracyclinesdiscolored teeth
chloramphenicolgray baby
metromutagenesis in 1st trimester

Kills spores

Question Answer
hydroxygen peroxideyes

Infection Control Technique

Question Answer
pressurized steam. may be sporicidialautoclave
denatures proteins and disrupts cell membranes. not sporicidalalcohols and chlorhexidine
free radial oxidation. sporicidalhydrogen peroxide
iodine and iodophorshalogenation of DNA, RNA and proteins. may be sporicidal.

Recent badges