Bacterial Pathogenesis and Virulence Factors Flashcards
Breach of new host defenses
- infectivity
The degree of pathogenicity of a microorganism as indicated by its ability to invade the tissues of the host and cause disease
- Virulence
- > generally multifactorial
Endotoxins in small or large quantities activates febrile responses causing fever/vasodilation
- small quantities
What is the establishment of a population of bacteria on host’s mucosal surface?
- Colonization
What term is used to describe pathogens that cause disease in immune compromised animals?
- opportunistic pathogens
The process by which bacteria infects and causes disease in a host
- bacterial pathogenesis
What is the penetration of host cells and tissues?
- Invasion
Damage of host cells by toxins
- direct damage of bacteria to host
Staphylcoccus pseudintermedius
- opportunist pathogen and commensal pathogen
Organism that benefits from another organism, but does not affect this second organism positively or negatively
- Commensal bacteria
- > mutual relationship host and bacteria benefit
- > protective function - inhibit pathogens via competition
What is the process by which bacteria can cause disease?
- bacterial pathogenesis
Normally not a pathogen if host functioning normally, but can cause disease when given the opportunity
- Opportunist pathogen
- > during stress, immune suppression, etc
Exotoxins are produced by?
- gram positive and negative bacteria
In gram positive bacteria what elicits septic shock?
- peptidoglycan and teichoic acid
An organized community/aggregation of bacteria that exchange products
- biofilm
- > occurs during transition from planktonic growth to biofilm caused by environmental condition change
When are endotoxins released?
- during bacterial cell lysis and death
Organism that invades or establishes itself in tissues that have been infected by a primary agent
- secondary pathogen
Toxin that destroys nerve cells
- neurotoxin
Organism that must infect host in order to survive and spread from one host to another
- obligate pathogen
Stimulate host immune response
- indirect damage of bacteria to host
Toxin produced in and affects the intestines
- enterotoxin
Endotoxins in small or large quantities activates endotoxic shock
- large quantities
Are endotoxins or exotoxins proteinaceous/enzymes
- exotoxins
What step in bacterial pathogenesis is necessary to avoid innate host defense mechanism?
- Adhesion
What are the effects of exotoxins?
- most are potent toxins and cause acute illness
Ex: Anthrax, botulism and cholera
Prevents attachment of antibody to antigen and inhibits phagocytosis
- bacteria capsule
- > makes cell larger and harder to engulf
Toxin that destroys cells
- cytotoxin
The toxic component of LPS in endotoxins
- Lipid A
Toxin produced in and affects the kidney
- nephrotoxin
What are the essential nutrients for bacterial growth?
- IRON, oxygen and suitable temps
Endotoxins are a component of gram positive or gram negative bacteria?
- gram negative bacteria
- > component of the bacterial cell wall
What term is used to describe pathogens that cause disease in healthy animals?
- primary pathogens
What is commensal bacteria? Give examples
- mutual host/bacteria relationship where both benefit
Ex: E. coli and Staphylococcus pseudintermedius
Organism that can initiate disease on its own
- primary pathogen
When are exotoxins released?
- by intact living bacteria and are secreted into the surrounding environment, injected into host cell, or enter via invasion of host cell
What is the ability of a pathogen to harm the host?
- virulence
