Antibiotics — Flashcards

Flashcard 551: What is the initial treatment of choice for most patients with early localized Lyme disease? _____

Answer: Oral doxycycline

Flashcard 552: What is the treatment for **prosthetic valve endocarditis** caused by methicillin-susceptible staphylococci? _____

Answer: Nafcillin (or oxacillin, cefazolin) + Rifampin + Gentamicin

Flashcard 553: What drug regimen is most commonly used to treat active tuberculosis? _____

Answer: (1) Rifampin (2) Isoniazid (3) Pyrazinamide (4) Ethambutol (And Vitamin B6)

Extra:  https://onlinemeded.org/spa/infectious-disease/tb/acquire?ref=anki 

Flashcard 554: Tazobactam, sulbactam, and clavulanic acid are _____ that can be added with amoxicillin, ampicillin, or piperacillin to extend their activity to cover gram (+) and (-)

Answer: β-lactamase inhibitors

Extra:  https://onlinemeded.org?ref=anki 

Flashcard 555: Meningitis is treated empirically with _____ and _____; add ampicillin if Listeria is suspected

Answer: ceftriaxone

Extra:  https://onlinemeded.org?ref=anki 

Flashcard 556: What is the recommended treatment for spontaneous bacterial peritonitis? _____

Answer: Broad-spectrum antibiotics (e.g. cefotaxime)

Extra:  https://onlinemeded.org/spa/gastroenterology/cirrhosis/acquire?ref=anki 

Flashcard 557: What is the mechanism of action of Nitrofurantoin?

Answer: Bacterial enzymes (flavoproteins) reduce it to reactive intermediates that damage bacterial DNA

Extra: Nitrofurantoin is primarily used for uncomplicated urinary tract infections (cystitis). It is bactericidal and achieves high concentrations in the urine. It is contraindicated in patients with significant renal impairment (CrCl < 60 mL/min) because it won't reach therapeutic concentrations in the urine and may cause systemic toxicity.

Flashcard 558: What is the mechanism of action of **Metronidazole**?

Answer: Forms toxic free radical metabolites that cause **DNA strand breakage** and loss of helical structure.

Extra: Metronidazole is a pro-drug that is reduced by the enzyme ferredoxin in anaerobic organisms. The resulting reactive metabolites damage bacterial DNA. Clinical use (mnemonic **GET GAP**): - **G**iardia - **E**ntamoeba - **T**richomonas - **G**ardnerella vaginalis - **A**naerobes (Bacteroides, C. difficile) - **P**ylori (H. pylori)

Flashcard 559: What is the susceptibility of monobactams (aztreonam) to beta-lactamases?_____

Answer: Resistant

Flashcard 560: Reversible inhibition of growthBacterio-_____

Answer: static