antibiotic therapy and resistance

• commensal bacteria 


  work in synergy with humans to make life possible
• pathogenic bacteria


  cholera, typhoid, tuberculosis, legionnaire's disease
• toxigenicity 


  bacteria produce toxins which damage specific tissue of the host (food poisoning or cholera)
• invasiveness


  multiply rapidly at sight of infection (pneumonia)
• secondary infection 


  bacteria invade bloodstream and set up other sites of infection
• bacteriostatic 


  inhibits growth of bacteria
• bactericidal 


  inhibits survival of bacteria
• inhibitors of cell wall synthesis 


  penicillins, cephalosporins, glycopeptides
• inhibitors of protein synthesis 


  tetracyclines, macrolides, amino-glycosides
• inhibition of DNA/RNA synthesis 


  quinolones
• inhibition of DNA/RNA precursor synthesis

  sulfa drugs
• mechanisms of antibiotic resistance

  1. pump out the antibiotic 2. modify the target of the antibiotic 3. destroy or neutralise the antibiotic
• origins of resistance 


  large number and short generation time, genetic versatility, horizontal gene transfer