Ch 85: Drugs That Weaken the Bacterial Cell Wall II: Cephalosporins, Carbapenems, Vancomycin, Telavancin, Aztreonam, and Fosfomycin Flashcards
The cephalosporins are beta-lactam drugs, but there are 3 exceptions. What are they?
Vancomycin, telavancin, and fosfomycin
p. 1025
What are beta-lactamases?
Enzymes that cleave the beta-lactam ring, rendering the drug inactive.
(p. 1025)
Which 5th generation cephalosporin has demonstrated activity against MRSA?
Ceftaroline (Teflaro)
p. 1025
What is the only 4th generation cephalosporin?
cefepime (Maxipime)
p. 1026
Cefepime is highly _________ to ____-__________, has a very _____ _____________ ________, and penetration to the ___ is ____.
Resistant to beta-lactamases
Broad antibacterial spectrum
CSF is good
(p. 1026)
Practically all cephalosporins are eliminated by…
One notable exception is…
…the kidneys.
…ceftriaxone (Rocephin).
(p. 1027)
Which two cephalosporins can cause bleeding tendencies?
By what mechanism do they do this?
Cefotetan and ceftriaxone
reduction of prothrombin levels through interference with vitamin K metabolism
(p. 1027)
What serious immune-mediated reaction can be induced by cephalosporins?
hemolytic anemia
p. 1027
Just as with penicillins, probenecid delays…
…renal excretion of some cephalosporins, prolonging their effects.
(p. 1027)
What combination of drugs can form a potentially fatal precipitate?
ceftriaxone (Rocephin) and IV calcium
p. 1027
What are the 2 prime rules of antimicrobial therapy?
Match the drug with the bug, and use a drug whose spectrum is no broader than required.
(p. 1028)
What 4 carbapenems are available?
imipenem, meropenem, ertapenem, and doripenem
p. 1029
Are any of the carbapenems active against MRSA?
No
p. 1029
What interaction occurs between imipenem and valproate?
Imipenem can reduce blood levels of valproate.
p. 1030
In general, how would you describe the class of carbapenems?
Carbapenems are beta-lactam antibiotics with a very broad antimicrobial spectrum.
(p. 1029)
Resistant organisms have emerged when P. aeruginosa is treated with imipenem alone, so it should be…
…combined with another antipseudomonal drug when used against this microbe.
(p. 1030)
What kind of microbe is Pseudomonas aeruginosa?
What should you know about it?
It’s an aerobic gram-negative rod
Most healthy people don’t get infected by this bug bc it has weak invasive abilities. In immunocompromised patients, it is a common cause of pneumonia.
(p. 81 of Clinical Microbiology Made Ridiculously Simple)
What mnemonic should you remember for Pseudomonas aeruginosa?
C BE PSEUDO
(corneal infections, burns, endocarditis, pneumonia, sepsis, external malignant otitis media, UTI, diabetic osteomyelitis)
(p. 82 of Clinical Microbiology Made Ridiculously Simple)
What kind of microbe is Clostridium difficile?
gram-positive, spore-forming, anaerobic bacillus
p. 1031
What is virulence?
the ability of an organism to cause disease
What is NAP1/BI/027?
A particularly virulent strain of C. diff.
p. 1031
Intensive use of ________________, such as ____________ [_____] and ____________ [________], is believed responsible for the rapid spread of the NAP1/BI/027 strain.
fluoroquinolones,
Ciprofloxacin [Cipro] and levofloxacin [Levaquin]
(p. 1031)
Vancomycin is active only against…
…gram-positive bacteria.
p. 1031
What is the cause of red man syndrome associated with rapid infusion of vancomycin and what are possible symptoms?
They result from histamine release.
Flushing, rash, pruritus, urticaria, tachycardia, and hypotension.
(p. 1033)
