Flashcards in anti-bacterials Deck (25):
what are two cefalosporins that have coverage against pseudomonas?
cetazidime (3rd gen)
cefepime (4th gen)
what gram negatives are covered by ceftriaxone?
what type of antibiotic should not be combined with a loop diuretic due to the risk of ototoxicity?
remember "mean GNATS caNNOT kill anaerobes"
nephrotoxicity, neuromuscular blockade,
what antibiotic causes grey baby syndrome?
chloramphenicol - especially in premature infants because they lack liver UDP-glucoronyl transferase
what antibiotic is known for causing pseudomembranous colitis (C. diff) along with fever and diarrhea?
clindamycin - used for anaerobic aspiration infections such as bacteroids or clostridium perfringens
what type of antibiotic causes discoloration of teeth and inhibition of bone growth in children?
what antibiotic cuases both dose dependent anemia and dose INDEPENDENT aplastic anemia as a potantial side effect?
Does TMP-SMX have activity against pseudomonas?
but DOC for pneumocystis jiroveci, toxoplasma gondii, nocardia
what should be given to alcoholic with pneumonia?
clindamycin - covers bacteroides, prevotella, fusobacterium and peptospreptococcus - anaeobic oral flora
also covers strep pneumoniea
binds 50S ribosomal subunit thereby inhibiting protein sysnthesis
what drugs act on the 50s ribosmal subunit?
chloramphenicol, clindamycin, linezolid and macrolides (e.g. azythromycin)
where do macroles and clindamycin bind what is the mechanisms?
23S rRNA of the 50S subunit - block trranslocation of the ribosome on mRNA and inhibit protein synthesis
what is the resistance to macrolides?
bacterial aquisition of genetic material encoding methylation of the 23S sRNA inhibits macrolide binding
how is resistance to cephalosporins accomlished?
hydrolize the drug with cephalosporinases
what is the mechanism of doxy/tetracycline?
bind to 30S, block aminoacryl-tRNA binding to the A site of on the ribosome and inhibit ELONGATION
how is resistance to tetracyclines accomlished?
decreased uptake and increased transport out of the cell, chemical modification of the drug
what is the mechanism for fluoroqinolones (e.g. moxifloxacin)?
inhibit DNA replication by binding to and stabilizing DNA-DNA gyrase (topo II) complex
how is resistance to fluoroquinolones accomlished?
mutations that alter binding to DNA gyrase
what is the mechanisms for vancomycin?
inhibit cell wall synthesis by binding to the D-alanyl-D-alanine bacterial cell wall
how is resistance to vancomycin accomlished?
replacement of D-alanine with D-lactate
what drug must travel through porin channels in bacterial out membrane and require and energy dependent mechanism to cross the bacterial inner membrane before binding to the 30S subunit?
what is the mechanism of resistance for aminoglycosides?
decreased drug penetration or altered ribosomal binding sites
penecilins can increase aminoglycosides ability to penetrate in resistant bacteria
what is the mechanism of resistance for trimethoprim or suylfamethoxazole?
decreased permeability, modified enzyme binding
imipenem is given along with another drug. What is it and how does it work?
functions to prevent proximal renal tubular brush boarder hydrolysis of imipenem by dehydropeptidases (depeptidase) which prolongs imipenems antimicrobial effects in the URINE
pt has a postive FTA-ABS result and is gen what two drugs? One is for the infection. What is the purpose and mechanism of the second drug?
Penicillin G and probenecid
FTA-ABS = fluorescent treponemal antibody absoption assay aka positive for syphalis
probenecid is given to prevent renal tubular secretion of penecillin. It works by inhibiting organic anion transper (OAT) in the renal proximal tubule
probenecid also blocks the urate transporter in the same cells, which decreases reabsoption of uric acid