Micro-organisms of disease Flashcards
Define pathogenicity
the capacity of a micro-organism to cause an infection
What are the 4 requirements of a pathogen?
transmissibility, establishment in or on host, harmful effects, persistence
What are the 6 stages of the chain of infection?
pathogenic organism, resevoir, exit source, transmission, entry into host, susceptible host…
Define virulence
degree to which a micro-organism is able to cause disease (interchangable with pathogenicity)
Give some examples of routes of transmission (4)
faecal-oral, blood bourne, respiratory, direct contact
Define infectivity
the ability of a micro-organism to become established on/in a host
What is the ligand-receptor interaction between E. coli and human uroepithelial cells?
fimbriae on E. coli and glycolipids on uroepithelial cells
Define virulence factors
components of micro-organisms that result in harmful effects
What are adhesins, aggresins, interferins and modulins examples of?
virulence factors
Describe an endotoxin
component of the gram-negative bacterial cell wall, released from damaged/dead cells
What term is lipopolysaccharide (LPS) often interchangable with?
endotoxin
What 3 uncontrolled reactions are part of systemic inflammatory response syndrome?
uncontrolled T-lymphocyte response, uncontrolled activation of clotting cascade, uncontrolled activation of complement
What is neisseria menigitidis?
endotoxin-induced increase in vascular permeability causes loss of protein, fluid and plasma into tissue
What are exotoxins?
proteins produced by living bacteria, usually with quite specific effects on host
What bacteria causes botulism?
Clostridium botulinium
