Resistance to antibiotics
Considerable importance as it renders current antimicrobials ineffective.
Organisms can become less susceptible or loose sensitivity to drug over time.
Mechanisms of microbe drug resistance:
• microbes may synthesis enzymes that metabolise the antibiotic (eg increased synthesis of pencillinase)
• microbes do not take up the antibiotic if mechanism of action is intracellular (eg resistance to tetracyclines)
• receptors on surface of microbe undergo changes(s)
• microbes may synthesise compounds to antagonise drug actions
Mechanisms by which resistance is acquired:
• spontaneous mutation (random changes in microbes DNA)
Antibiotic use and development of drug resistant organisms:
If a drug resistant organism is present, antibiotics create the environment in which selection favours that organism.