1. Introduction to antibacterial agents
Aims: To discuss the mechanisms of action, antimicrobial spectra and adverse event
profiles of the major classes of antimicrobial agents.
Objectives: Be able to provide examples of antibacterial agents in common use;
Be able to describe the mechanisms of action of the major classes of antibacterial
agents at a basic level;
Be able to describe the common adverse events of the major classes of
antibacterial agents at a basic level.
BACKGROUND
Antibiotics -Chemical products of microbes that inhibit or kill other organisms
Antimicrobial agents (antibacterial, antifungal, antiviral)
– Antibiotics
– Synthetic compounds with similar effect
– Semi-synthetic i.e. modified from antibiotics
• Different antimicrobial activity/spectrum, pharmacological
properties or toxicity
Bacteristatic -Inhibit bacterial growth (Protein synthesis inhibitors)
Bactericidal -Kill bacteria (Cell wall-active agents)
Minimum inhibitory concentration – MIC- Minimum concentration of antibiotic at
which visible growth is inhibited
Some antibiotics are bacteristatic at low concentrations and bactericidal at high
concentrations
Synergism -Activity of two antimicrobials given together is greater than the sum of
their activity if given separately
Antagonism -One agent diminishes the activity of another
Indifference -Activity unaffected by the addition of another agent
Clinical relevance -Synergism
-β-lactam/aminoglycoside combination therapy of streptococcal
endocarditis
Aims: To discuss the mechanisms of action, antimicrobial spectra and adverse event
profiles of the major classes of antimicrobial agents.
Objectives: Be able to provide examples of antibacterial agents in common use;
Be able to describe the mechanisms of action of the major classes of antibacterial
agents at a basic level;
Be able to describe the common adverse events of the major classes of
antibacterial agents at a basic level.
BACKGROUND
Antibiotics -Chemical products of microbes that inhibit or kill other organisms
Antimicrobial agents (antibacterial, antifungal, antiviral)
– Antibiotics
– Synthetic compounds with similar effect
– Semi-synthetic i.e. modified from antibiotics
• Different antimicrobial activity/spectrum, pharmacological
properties or toxicity
Bacteristatic -Inhibit bacterial growth (Protein synthesis inhibitors)
Bactericidal -Kill bacteria (Cell wall-active agents)
Minimum inhibitory concentration – MIC- Minimum concentration of antibiotic at
which visible growth is inhibited
Some antibiotics are bacteristatic at low concentrations and bactericidal at high
concentrations
Synergism -Activity of two antimicrobials given together is greater than the sum of
their activity if given separately
Antagonism -One agent diminishes the activity of another
Indifference -Activity unaffected by the addition of another agent
Clinical relevance -Synergism
-β-lactam/aminoglycoside combination therapy of streptococcal
endocarditis
