C.17. Glycopetides. Fusidans, Lipopetides. Bacitracin. Mupirocin. Pharmacotherapy of skin and soft tissue infection. Flashcards
what is the mechanism of action of Glycopeptides Ab?
- Bactericidal effect
- interfere with cross-linking. GP’s Binds at the D-ala-D-ala terminal –> inhibits the elongation of peptidoglycan chains
list the Glycopeptide antibiotics
Vancomycin
Teicoplanin
Oritavancin
Mupirocin
how are vancomycin, teicoplanin and Oritavancin given?
Parenterally
*not absorbed orally –> benefit in bacterial colitis treatment
what strains are resistant to Vancomycin, teicoplanin and Oritavancin. what is the mechanism of resistance?
VRSA -vancomycin-resistant S. aureus
VISA- vancomycin intermediate S.aureus
VRE-vancomycin resistant Enterococci
most β-lactamases
alteration of the terminal D-ala to D-lactate
what is the spectrum and clinical uses of Vancomycin and Teicoplanin? (6)
Narrow spectrum:
- gram + bacteria
- MRSA and PRSP
- Clostridium difficile (2nd line)
- empiric treatment: endocarditis, meningitis (with 3 gen’ cephalosporins)
- osteomyelitis
- prosthetic joint infection
what is the spectrum and clinical uses of Oritavancin?
narrow spectrum:
- gram + bacteria, anerobic and aerobic
- severe skin infection
what is the T1/2 of Vancomycin and teicoplanin?
6 hours
do vancomycin and Teicoplanin require monitoring of drugs plasma concentrations?
yes, have a narrow therapeutic index
adverse effects of Vancomycin and Teicoplanin?
chills, fever
injection site phlebitis
ototoxicity
nephrotoxicity (when given with aminoglycosides)
DRESS syndrome
diffuse flushing–>’red man syndrome’ when given rapid IV administration due to histamine release
how do we avoid ‘red man syndrome’ when giving Vancomycin and Teicoplanin?
slow injection
what is more toxic- vancomycin or Teicoplanin?
vancomycin
side effects of Oritavancin?
GI symptoms
elevated liver enzymes
elevated CK
what is the mechanism of Mupirocin
inhibits bacterial protein synthesis by selectively binding to isoleucyl-tRNA synthetase
when do we give Mupirocin?
- gram +cocci
- impetigo caused by staph (MRSA), S.pyogenes
- nasal carriage of S. Aureus (intranasal ointment)
who do we give intranasal ointment Mupirocin for S. aureus nasal carriage?
medical workers
how do we give Mupirocin?
topically (not absorbed)
side effects of Mupirocin
local itching and burning
rash, erythema, contact dermatitis
what is Daptomycin?
Lipopeptide Ab
depolarization agent
what is the mechanism of action of Daptomycin
Bactericidal effect
enters the cytoplasmic membrane (irreversibly)–> disrupts ionic gradients and membrane depolarization
what has a more rapid effect- daptomycin or vancomycin?
daptomycin
what is the spectrum of daptomycin?
narrow
gram +
MRSA,VRSA ,VRE
How is daptomycin given?
parenterally
how is daptomycin eliminated in the body?
renal
what inhibits daptomycin and when it shouldn’t be given?
pulmonary surfactant
cannot be used to treat pneumonia
side effects of daptomycin
myopathy (additive with statins)–> monitor creatine phosphokinase
Rhabdomyolysis (rare)
pneumonitis (therapy >2 w’)
what Ab are polypeptides?
bacitracin and fusidic acid
is Bacitracin bacteriostatic or bactericidal?
both (depends on the concentration)
how is Bacitracin given?
topically (wounds)
too toxic for systemic use –> nephrotoxicity
what does bacitracin do?
inhibits the precursor translocation across the bacterial membrane
what is Neomycin-Bacitracin- Polymyxin B?
ointment preparation, over the counter drug (Neosporin)
prevent and treat minor skin infection
how is fusidic acid given?
topical/parenteral
when do we give systemic fusidic acid (fusidans)?
MRSA infection
when do we give topical fusidic acid?
skin infection (cellulitis, impetigo), conjunctivitis
what other indications are there for fusidic acids, other than skin infections are MRSA?
gram +
aerobes and anaerobes
corynebacterium endocarditis
what is the mechanism of fusidic acids (fusidans)?
bacteriostatic effect
inhibitor of bacterial protein synthesis (inhibits translocations-elongation factor G)
what side effect does fusidic acid cause in systemic use?
hepatotoxicity
what is the 1st line topical treatment for Cellulitis &impetigo?
fusidic acid
Mupirocin
Polymyxin E (colistin)
what is the 1st line treatment for Cellulitis &impetigo in case of staphylococcal or streptococcal infection?
Nafcillin IV or Oxacillin IV
what is the alternative treatment for Cellulitis &impetigo in case of staphylococcal or streptococcal infection?
Cefazolin IV or
Ampicillin/Sulbactam IV
what is the 1st line treatment for Cellulitis &impetigo in case of MRSA infection?
vancomycin IV
what is the alternative treatment for Cellulitis &impetigo in case of MRSA infection?
Linezolid IV
what is the 1st line treatment for Necrotizing fasciitis?
Clindamycin IV and Penicillin-G IV
what is the 1st line treatment for gas gangrene (C.perfringes)?
Clindamycin IV and Penicillin-G IV
what is the alternative treatment for Necrotizing fasciitis?
Clindamycin IV and Cephalosporin IV
what is the alternative treatment for gas gangrene (C.perfringes)?
Clindamycin IV and Cefoxitin IV
