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•  Experiments showing zone of inhibition of bacterial growth by bactericides in sterile bacterial cultures

Bactericides are substances which kill bacteria – they include certain types of disinfectants, antiseptics and antibiotics

  • Whereas bactericidal agents will kill bacteria, bacteriostatic agents function by slowing their growth and reproduction

The efficacy of a particular bactericide can be tested by examining its effect on bacterial growth in a sterile bacterial culture

  • If a bactericide is effective against a particular bacterial strain, there will be no growth around the agent (zone of inhibition)
  • The larger the zone of inhibition, the more effective the bactericidal agent is at killing the bacterial strain

The zone of inhibition will also be affected by the solubility of the bactericide (i.e. fast diffusion rate = large zone of inhibition)

  • This is an important consideration when testing multiple bactericides on the same growth medium

Effect of Bactericides on Bacterial Growth