Antibiotics for Infective Endocarditis Flashcards
Antibiotics that block peptidoglycan cross-linking (block PBPs)
B-lactams: Penicillin, Cefazolin, Ceftriaxone
Resistance to B-lactams
mutations in PBPs that prevent binding of B-lactam antibiotic
Peptidoglycan inhibitor that binds D-ala-D-ala at end of peptide side chain in peptidoglycan precursors
Glycopeptides: Vancomycin
Resistance to glycopeptides
Modification of antibiotic target–bacteria acquire genes encoding machinery to produce altered peptidoglycan structure that lacks D-ala-D-ala groups –> vanco is unable to bind
Associated with Enterococci in hospital setting
Lipopeptide antibiotic, binds and disrupts cytoplasmic membrane, possible via loss of mem. potential, leading to death
Daptomycin
Binds to and inhibits RNA pol to prevent gene expression
Rifampin
Resistance to Rifampin
Point mutations in RpoB subunit of RNA pol
Protein synthesis inhibitors– targeting 30S function, causing misreading and premature release of ribosome from mRNA
Aminoglycosides–Gentamicin
SE of aminoglycosides
Ototoxic and nephrotoxic
Resistance to Gentamicin
Enzymatic modification of antibiotic to prevent binding to ribosome
Treatment of Strep endocarditis
Penicillin susceptible
Penicillin of ceftriaxone x 4-6 wks
Vancomycin x 4-6 wks
Treatment of Strep endocarditis
Penicillin intermediate
Pen or ceph x 4-6 wks w/ Gent x 2-6 wks
Vanco x 4-6 wks
Treatment of Enterococci
Pen or amp x 4-6 wks with Gent x 2-6 wks
Vanco w/ Gent x 6 wks
Treatment of Staph endocarditis
Native valve
6 wks:
Nafcillin or Oxacillin (+/- Gentamicin x 3-5 days)
Cefazolin (+/- Gentamicin x 3-5 days)
Vancomycin
Treatment of Staph endocarditis
Prosthetic valve
6 wks:
Nafcillin or oxacillin + Rifampin (+/- Gent x 2 wks)
Vancomycin + Rifampin (+/- Gent x 2 wks)
