BACTERIAL PATHOGENESIS 1 Flashcards
what is the major threat related to bacterial pathogens?
antimicrobial resistance
what are two modern big bacterial killers?
tuberculosis and pneumonia
how was the bacterial cause of ulcers determined?
people thought that ulcers were caused by stress or spicy food
dr marshall knew that it was caused by infection, but people were skeptical
attempts to culture the bacteria fro ulcers were unsuccessful
dr marshall drank the cultures and got ulcers
he treated himself and got a nobel prize
the bacteria is Helicobacter
characteristics of Helicobacter pylori
how do you define a pathogen with Koch’s postulates?
what are some caveats of koch’s postulates?
what is an infection
when pathogen becomes established in the body
what is a disease?
infection which produces signs and symptoms
what is a symptom vs a sign?
what is asymptomatic carriage?
infection without disease
how does Pseudomonas aeruginosa infect people with cystic fibrosis?
what is a secondary infection?
an infection that develops in an individual who is already infected with a different pathogen
example: tuberculosis kills people with HIV at more than 50%
how does microbiome impact susceptibility?
gut microbiome protects us from potentially harmful bacteria
when people are treated with antibiotics, you kill the good bacteria and you get a blood of the bad bacteria
an example of this is C. difficile infection following antibiotic treatment
what are the required steps of pathogenesis of bacterial diseases?
how do bacteria maintain a reservoir?
the reservoirs are specific for each pathogen
what are some common reservoirs for human pathogens?
who is typhoid mary
what are two methods of transport of pathogen to the host?
direct or indirect
what are methods of direct transport of the bacterial pathogen to the host?
droplet= short range, short lived
airborne=longer lived, suspended in the air
what are methods of indirect transport of the bacterial pathogen to the host?
how do bacteria carry out adherence/colonization/invasion?
what are types of bacteria adhesins?
what do adhesins do?
how can 1 amino acid in receptors make all the difference
how can invasion of bacterial pathogen be an active penetration into host cell
salmonella loves to live inside host cell
type 3 secretion system: injects bacterial proteins into host cell
zombifies actin cytoskeleton
actin rearranges and brings salmonella inside the host cell
how can invasion of bacterial pathogen be an active penetration between host cells
tight junctions are relatively impenetrable, but bacteria have ways to chew through those junctions to move between cells
how can invasion of the bacterial pathogen be passive?
how do bacteria multiply/complete their life cycle in the host
suitable environment varies a lot from pathogen to pathogen
intracellular/extracellular pathogens
sme bacteria invade specific cells and have adapted strategies to live inside
how do bacteria evade host defenses?
bacteria must have mechanisms to resist hose defenses: complement system, phagocytosis and specific immune responses
bacteria have ways of neutralizing ROS
what is the bacterial capsule?
composed of chemicals not recognised as foreign, slippery and difficult for phagocytes to engulf
how do bacteria leave the host?
