Antimicrobial modes of resistance Flashcards
(18 cards)
How do bacteria inactivate B lactam antibiotics?
Production of B lactamases - break open B lactam ring.
What is clauvulanic acid?
B lactamase inhibitor
What is tazobactam?
B lactamase inhibitor
What is sulbactam?
B lactamase inhibitor
How does resistance to vancomycin occur?
Altered target site. Change in terminal AA of peptide side chain.
D-ala-D-ala becomes D-ala-D-lactate.
Change to NH leads to the formation of 5 H bonds (instead of 4) and so a stable complex is formed and vancomycin is less effective.
What are gram negative bacteria intrinsically resistant to vancomycin?
Cannot penetrate the cell membrane
What % of gram positive bacteria are resistant to vancomycin?
10%
What is AcRAB/TolC?
Antimicrobial multi-antibiotic resistance efflux. in e.coli.
What type of penicillin is benzylpenicillin?
B lactamase sensitive
How is benzypenicillin (Pen G) administered?
IV or IM
What type of penicillin is Flucloxacillin?
B lactamase resistant
What is the standard dose of benzylpenicillin?
1.2g fours times a day
What is the dose of benzylpenicillin used for endocarditis?
2.4g every 4 hours
What antibiotic should be used immediately if meningitis is suspected?
Benzylpenicillin
What is the oral BA of amoxicillin?
70-90%
What are the side effects of penicillins?
Hypersensitivity
Neurotoxicity
Renal failure
Diarrhoea, c.diff
What causes c.diff?
Oral broad spec AB kills gut bacteria
Resistant pathogenic gut bacteria causes superinfection
Where do we isolate Cephalosporins from?
Cephalosporin acremonium
