Microbial Pathogens

Microbial Pathogens

1. Definitions

   • infection = site where it is normally absent
   • Pathogenicity = ability
   • Virulence = measure ^
   • colonisation = established and growing in a host
     • Virulence helps colonisation
   • Disease = damage done by the pathogen or your bodys responce
   • Parenteral = skin penetration
   • conjunctiva = muscus lining eyball
   • skin flora = skin microbe help fight
   • Attenuation = decrease of virulence

2. General Process

   • pathogens use various strategies to cause disease
   • general process of pathogenesis is similar

3. Toxins

   • Endotoxins
     • Part of the cell
   • Exotoxins
     • Secreteod frm pathogen
     • Cytolytic
       • attacks membrane causes cell lyses
         • a = partial
           • b= fully
             • y=non
             • Inactivation of protine function
           • Formes pores in membrane
     • AB toxin
       • Block release of neurotransmitters
       • Botulinum toxin
         • blocks relese of Acetylecholine so inhibits contraction
     • Entertoxins
       • Affect small intestine
       • causes secretion on ions
         • causes water to go to lumen
   • Superantigens

4. Adherence

   • Attach to tisue
     • must gain access to host cell
   • invasion
     • Virulence factors = molecules produced by pathogens that contribute to pathogenicity
       • Kochs postulates used to confirm
     • Spread
       • produce enzymes
         • breaks down cell
       • use cells defence mechanism eg slime
   • Highly specific