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