Unit 2: 15.2 Flashcards
Pathogenicity
Ability of microbial agent to cause disease
Virulence
The degree to which an organism is pathogenic
Lower number = more virulent
Do virulent pathogens almost always lead to disease?
Yes
ID 50
Number of pathogenic cells requires to cause active infection in 50% of inocculated animals
LD 50
Number of pathogens/toxins required to kill 50% of infected animals
Primary pathogen
Can cause disease in a host regardless of the hosts resident microbiota/immune system
Opportunistic pathogen
Can cause disease in people who are immunocompromised
Ex: Staphylococcus epidermidis
Stages of pathogenesis
- Exposure (contact)
- Adhesion (colonization)
- Invasion
- Infection
Portal of entry
An anatomic site through which pathogens can pass into host tissue
Major portals of entry
- Skin
- Mucous membranes
- Parental routes
Adhesins
Made of proteins or carbohydrates found on surface of certain pathogens and bind to specific receptors (glycoproteins) on host cells
Biofilm
Community of bacteria that produce a glycocalyx known as EPS
EPS
Allows biofilm to attach to a surface
-provides protection against the immune system and antibiotic treatments
Local infection
Confined to a small area of the body typically near the portal of entry
Focal infection
The toxins it produces can spread to a second location