Bacterio Flashcards
Peripheral neuropathy is caused by INH by?
Increasing the urinary excretion of vit B6 → defective synthesis of neurotransmitters like GABA
Seizures in isoniazid are refractory to?
Benzodiazepines
INH resistance?
- ↓ Kat G expression
2. Genetic modification of INH binding site on mycolic acid synthesis enzymes
Why rifabutin preferred over rifampin in HIV patients?
Due to less stimulation of cyp 450
Meningitis treatment coverage?
Ceftriaxone
Vancomycin :For resistant Strep. Pneumo
Ampicillin in old and child for listeria
Role of CYP450 in excretion of penicillin?
No role
it is excreted renally
Organisms not covered by 1-4 cephalosporins?
LAME listeria (resistant PBP)--- Ampicillin atypicals (chlamydia, mycoplasma)--- [no cell wall] MRSA (resistant PBP)---5th Gen Enterococci (resistant PBP)-----5th Gen
Monobactams include?
Clinical use?
Aztreonam
- Aerobic Gram -ve rods only
- Penicillin allergic patients
- Renal insufficiency patients who can’t tolerate aminoglycosides
Monobactams used synergistic with?
Aminoglycosides
Cilastatin MOA?
Inhibitor of renal dehydropeptidase 1
Difference in MOA of vancomycin and penicillin?
Penicillins are D-Ala D-Ala analogs that binds PBP and inhibit cross linking of peptidoglycan (last step)
Vancomycin binds to D-Ala D-Ala directly and inhibit peptidoglycan synthesis. (a step before the last step) making MRSA PBP ineffective
Vancomycin has activity against _____ only?
gram +
Disrupts cell MEMBRANE integrity?
Daptomycin gram +
Polymyxin gram -
Peptidoglycan synthesis inhibition?
Vancomycin
Bacitracin
Polymyxin adverse effects:
- neurotoxic
- respiratory failure
- nephrotoxic
Macrolides adverse effects?
Rash. Eosinophilia
↑ conc of theophylline and oral anticoagulants
Erythro, clarithro → CYP450 inhibitor
mechanism of Resistance to macrolides?
Methylation of 23s rRNA-binding site
