Antibiotics for Cardiovascular Infections Flashcards
Acute rheumatic fever is a _______ reaction to infection with ___________, due to molecular mimicry; ARF is primarily found in children age 5-14
Autoimmune; Group A streptococcus
Who is at increased risk of exposure to streptococcal infections?
Children and adolescents, parents of young children, teachers, physicians, nurses, day-care workers, military recruits, individuals living in crowded situations (i.e., college dorms)
Empiric tx for ARF
Penicillin G + gentamycin
[Also give NSAIDs like ASA or ibuprofen for joint pain and fever]
Tx of ARF in pt with penicillin allergy or hypersensitivity to beta lactams
Macrolides: erythromycin, azithromycin, clarithromycin, or clindamycin
When it comes to concern for prophylaxis of recurrent ARF in a pt hypersensitive to beta lactams, what macrolide is avoided?
Clindamycin due to the chance of eliciting opportunistic infection of the GI tract by C.diff
Drugs that can still be used = erythromycin, azithromycin, clarithromycin
MOA of aminoglycosides
Protein synthesis inhibitors
AEs of aminoglycosides
Nephrotoxicity (reduced by not combining with vancomycin)
With high risk use (>75 days, high doses, elderly pt, pre-existing renal insufficiency, etc.), can lead to ototoxicity and auditory damage
Macrolides MOA
Protein synthesis inhibitor [stops tRNA at A site, conformational change in 50S, disruption of 50S formation]
4 resistance mechanisms associated with macrolides
Active drug efflux pumps
Methylase enzymes modify binding site
Degradation by esterases from enterobacter sp (cannot be used to tx infection with this etiology!)
Mutation of binding site itself
AEs associated with macrolides
GI distress (n/v/anorexia) — most frequent with erythromycin
Prolonged erythromycin use —> hepatotoxicity
Hypersensitivity —> eosinophilia, fever
T/F: macrolides should never be given with other abx
False — they are often combined with other abx for wide spectrum coverage
Prototypic lesion associated with IE
Vegetation
Oral cavity, skin, and upper respiratory tract organisms associated with IE
Oral cavity = streptococcus viridans
Skin = staph
Upper respiratory = HACEK
Empiric tx for IE
Vancomycin (must be given IV) + ceftriaxone
What drug options are utilized in IE d/t streptococcus viridans if highly penicillin susceptible organism?
Penicillin G or ceftriaxone
What drug options are utilized in IE d/t streptococcus viridans for shorter drug course, and if pt has no renal dz?
Gentamycin + Pencillin G
Gentamycin + ceftriaxone
What drug options are utilized in IE d/t streptococcus viridans if pt has mild penicillin allergy?
Ceftriaxone
Gentamycin + ceftriaxone
What drug options are utilized in IE d/t streptococcus viridans if pt has severe penicillin allergy?
Vancomycin, or perform penicillin desensitization (preferred)
How does penicillin desensitization work?
Small dose of drug that is gradually increased until the therapeutic dose is achieved [1 unit of drug is given IV and pt observed for 15-30min]
If no reaction —> dose gradually increased every 15-30 min (tenfold or doubling, depending)
Once 2 million units is reached, the remainder of the dose can be given
The sensitivity is d/t IgE-mediated allergic reaction, but slow exposure allows IgG to compete. Note that drug must be physically present to maintain desensitization (meaning this process must be repeated each time the pt gets PCN)
Drug(s) utilized for IE d/t S.aureus that is methicillin-susceptible
Nafcillin or oxacillin
Drug(s) utilized for IE d/t S.aureus in pt with mild beta lactam sensitivity
Cefazolin
Drug(s) utilized for IE d/t S.aureus in pt with severe beta-lactam hypersensitivity
Vancomycin or daptomycin
Drug(s) utilized for IE d/t S.aureus in pts with complication of a brain abscess
Nafcillin
Drug(s) utilized for IE d/t MRSA
Vancomycin or daptomycin (alternative)
Daptomycin is a new abx with similar spectrum of activity as vancomycin. It works on ________ organisms including MRSA
Gram positive
MOA of daptomycin
Not completely understood
Binds to cell membrane via Ca-dependent insertion of its lipid tail leading to depolarization, K+ efflux, and rapid cell death
Drug(s) utilized for IE d/t S.epidermidis and other coagulase negative staphylococci
Vancomycin
Drug(s) utilized for IE d/t HACEK infection
Ceftriaxone
Drug(s) utilized for IE d/t enterococci (mostly e.faecalis)
[penicillin G or ampicillin or vancomycin] + gentamycin
[note that vanco is chosen in pts with PCN allergy]
Pericarditis tx in immunocompetent pts
NSAID (i.e., ASA or naproxen) + colchicine
What lab test is important to order to track treatment of pericarditis?
CRP
_______ may be used to treat pericarditis in severe or refractory cases, but carry the risk of prolonging illness or increasing the chance of relapse
Corticosteroids (i.e., prednisone)
Colchicine has anti-inflammatory action mediated by binding to ______, preventing its polymerization and leading to inhibition of _____ migration and phagocytosis
Tubulin; leukocyte
AEs with colchicine
Diarrhea and occasional nausea, vomiting, and abd pain
No longer approved for IV use, but when it was used IV it carried risk of hair loss, bone marrow depression, peripheral neuritis, and myopathy
A 42-year-old patient presents to clinic complaining of a fever and unintentional weight loss. A diagnosis of infective endocarditis is made and blood cultures point towards infection with S. epidermidis.
Which pharmacologic agent would specifically target S.epidermidis in the setting of acute IE?
A. Penicillin G B. Moxifloxacin C. Aztreonam D. Methicillin E. Vancomycin
E. Vancomycin
What is the MOA of vancomycin?
Cell wall synthesis inhibitor; indirectly damages cell wall
A 54-year-old male patient was admitted to the hospital with fever (100.6 ºF, 38.1 ºC), joint pain, night sweats, and 15 lb (6.8 kg) of unintentional weight loss. Past history was significant for rheumatic fever at the age of 9 and for dental surgery 1 month ago. The symptoms started about 2 weeks after the dental procedure. Physical examination was significant for mitral regurgitation. Three blood cultures were ordered, and an empiric therapy was started.
Which of the following would be appropriate for the pt at this time?
A. Ampicillin and erythromycin B. Piperacillin C. Aztreonam D. Penicillin G and gentamicin E. Ciprofloxacin
D. Penicillin G and gentamicin
Why are penicillin G and gentamycin considered synergistic?
Cell wall active agents like penicillin G and ceftriaxone increase uptake of aminoglycosides like gentamicin
A 32-year-old female heroin addict was admitted to the hospital with a 2-day history of fever, shaking chills, rigors, and night sweats. Her vital sign were: blood pressure 100/60 mm Hg, pulse 120 bpm, respirations 24/min, temperature 102.2 ºF (39 ºC). Two-dimensional echocardiography revealed three small vegetations on the tricuspid valve. Three blood cultures were drawn and empiric therapy was initiated.
What drugs were initiated as empiric therapy?
A. Ceftriaxone and vancomycin
B. Gentamicin
C. Ciprofloxacin
D. Piperacillin and ceftriaxone
A. Ceftriaxone and vancomycin
A 32-year-old female heroin addict was admitted to the hospital with a 2-day history of fever, shaking chills, rigors, and night sweats. Her vital sign were: blood pressure 100/60 mm Hg, pulse 120 bpm, respirations 24/min, temperature 102.2 ºF (39 ºC). Two-dimensional echocardiography revealed three small vegetations on the tricuspid valve. Three blood cultures were drawn and empiric therapy was initiated. The patient does not respond to vancomycin and the blood cultures later reveal MRSA. What alternative drug could be used in this case?
A. Piperacillin B. Daptamycin C. Clindamycin D. Gentamicin E. Aztreonam
B. Daptamycin
