pathogens and the host Flashcards
what are signs and symptms of clinical infection
inflammation pain pyrexia tachycardia rigors increased white cell count Increased C reactive protein (CRP)
whats a pathogen
organism which can cause disease
whats a commensal
an organism which is part of normal flora e.g. E. coli in the gut, Staph aureus in the nose, axilla
whats pathogenicity
The capacity of a micro-organism to cause an infection
whats infectivity
Ability to become established on or within a host
whats virulence
Capacity to cause harmful effects (disease) once established
what are microbial components of virulence
Invasiveness
Toxin production
Evasion of immune system
what is groupA streptococci
Streptococcus pyogenes
what colour does alpha- haemolytic turn agar
green
what colour does beta- haemolytic turn agar
clear
what does clostridium tetani cause
tetanus, uncotrollable muscle spasm
what does cholera do
is it an enterotoxin?
colonises small intestinen, increases cAMP levels ( inhibits uptake of na amd cl ions
causes deathbu dehydration
yes
what do superantigens do?
able to stimulate division of T cells in the abscence of specific antigens
what is an enterotoxin
toxin prduced in or affecting the intestines
whats the differece between endotoxins and exotoxis
Exotoxins are toxic substances secreted by bacteria and released outside the cell. Whereas Endotoxins are bacterial toxins consisting of lipids that are located within a cell
what are the cmpents of endotoxins
has lipids and oligosacchardide core with O antigen
gram negative bacteria cell wall
what does Neisseria meningitis cause
Neisseria meningitis causes meningitis
what does Neisseria gonorrhoeae cause
urethritis in men, pelvic inflammatory disease in females
what does Enterohaemorrhagic E.coli cause
bloody diarrhoea
Requirements of pathogenicity are
infectivity and virulence
what are the 3 types of vaccine
live attenuated and killed and toxoid
