Antibacterial agents intro Flashcards
Define bacteristatic
Inhibit bacterial growth
Protein synthesis inhibitors
Define Bactericidal
Kill bacteria
Cell wall-active agents
Define Minimum inhibitory concentration – MIC
Minimum concentration of antibiotic at which visible growth is inhibited
Define Synergism
Activity of two antimicrobials given together is greater than the sum of their activity if given separately
Define Antagonism
One agent diminishes the activity of another
Define Indifference
Activity unaffected by the addition of another agent
What are the 2 main antibacterial mechanisms?
Inhibition of critical process in bacterial cells (Enzymes, molecules or structures)
Selective toxicity
(Target not present in human host or target significantly different in human host)
What are 5 main antibiotic targets in a bacterial cell?
Cell wall Protein synthesis DNA synthesis RNA synthesis Plasma membrane
What is the major component of bacterial cell walls?
Peptidoglycan
made up of NAM and NAG
Which 2 types of antibiotics are cell-wall synthesis inhibitors?
β-lactams
Glycopeptides
Name 4 β-lactam antibiotics categories
Penicillins
Cephalosporins
Carbapenems
Monobactams
Name 2 glycopeptide antibiotics
vancomycin, teicoplanin
What are the 4 main groups of protein synthesis inhibiting antibiotics?
Aminoglycosides
MLS (macrocodes, lincosamides, steptogramins)
Tetracyclines
Oxazolidinones
What are some examples of aminoglycosides?
Gentamicin, amikacin
What are some MLS antibiotics?
Erythromycin, clarithromycin
Clindamycin
Give an example of an oxazolidinone
Linezolid.
What are some DNA synthesis inhibitor antibiotic categories?
Trimethoprim, Sulfonamides,
Quinolones and fluoroquinolones
What are examples of quinolones?
nalidixic acid, ciprofloxacin, levofloxacin
What is Colistin?
Plasma membrane agent. Absolute last resort gram-negative antibiotic.
What is an RNA synthesis inhibitor?
Rifampicin
What are the antibiotic-specific adverse effects of aminoglycosides?
Reversible renal impairment on accumulation
Irreversible ototoxicity
Therapeutic drug monitoring indicated
What are the antibiotic-specific adverse effects of Β-lactams?
Main problems are allergic reactions
Generalised rash 1-10%
Anaphylaxis approx. 0.01%
What is the antibiotic-specific adverse effect of Linezolid?
Bone marrow depression
Which 4 antibiotics commonly precipitate C.Diff infection?
Co-amoxiclav (amoxicillin-clavulanate)
Cephalosporins
Ciprofloxacin (fluoroquinolone)
Clindamycin (MLS)
What is the key antibiotic combination for:
flucloxacillin?
Staphylococcus aureus (not MRSA)
What is the key antibiotic combination for:
benzylpenicillin?
Streptococcus pyogenes
What is the key antibiotic combination for:
cephalosporins?
gram-negative bacilli
What is the key antibiotic combination for:
metronidazole?
anaerobes
What is the key antibiotic combination for:
vancomycin?
Gram-positives (MRSA)
What is the key antibiotic combination for:
meropenem?
most clinically-relevant bacteria
When is combination therapy appropriate?
to increase efficacy
to provide adequately broad spectrum
to reduce resistance
