Culture Results and Antimicrobial Susceptibility

Minimum Inhibitory Concentration (MIC)

  • The MIC is the lowest concentration of antimicrobial that prevents visible growth (inhibits bacterial growth) in body tissues and fluids (measured visually)

  • Organism and antimicrobial specific

Susceptibility Reporting

Report organism(s) and susceptibilities to antimicrobials:

  • Susceptible (S) - The antimicrobial will be effective at achievable concentrations
  • Intermediate (I) - The antimicrobial may be effective at higher concentrations
  • Resistant (R) - The antimicrobial will not be effective at achievable concentrations

Important Considerations

Note: Drug must inhibit microorganism at lower concentrations than those that produce toxic effects in humans.

  • MBC = Minimum Bactericidal Concentration - the lowest concentration of antibiotic that kills bacteria (bactericidal effect)