class #7- more bacterial diseases Flashcards
what is virulence
the ability to cause damage to host cell
what is a virulence factor
how bacteria reach eukaryotic cell to help cause disease
what are the 5 bacterias studied in this lecture
Listeria monocytogenes
Staphylococcus aureus
Yersinia pestis
Escherichia coli
Salmonella typhi
what are the characteristics of Yersinia pestis
gram negative rod
causes the plague
spread through zoonosis
what are the 2 types of Yersinia pestis
Bubonic plague and Pneumonic plague
what is the Bubonic plague
acquired from animals (flea)
Y. pestis moves into the lymph nodes and results in necrosis and “buboes”
what happens when someone gets the Bubonic plague
death of tissue in hands, turn black
what is the Pneumonic plague
person-person transmission (inhalation)
replicates in lungs
what are the symptoms of the pneumonic plague
chest pain, fever, cough
what is the black death
outbreak of Y. pestis in 1300s in Europe (pandemic of 50 million dead)
what are the characteristics of Listeria monocytogenes
gram positive rod
causes Listeriosis
a big issue in the food industry b/c it can grow at 4 degrees celsius
how is Listeria monocytogenes spread
by contaminated food: meats, unpasteruized cheeses
who is most at risk for Listeriosis
pregnant women, elderly, immunocompromised
how does Listeria enter the epithelium
listeria are taken up into epithelial cells inside a phagocytic vacuole
what happens once listeria is in a cell
they escape the vacuole using lipase (Listeriolysin-O)
then they use ActA to polymerize actin to move around cell
what is Escherichia coli
E. coli, gram-negative bacteria
where are E.coli virulence factors located
on pathogenicity islands within their genome
what is the most common E. coli strain
O:157 serotype
What is a pathogenicity island
large pieces of DNA that encode virulence factors
what is E. coli O:157
associated with cattle, they carry O:157 but don’t get sick
E.coli O:157 symptoms
bloody diarrhea and Hemolytic Uremic Syndrome (HUS)
E.coli O:157 virulence?
T3SS and Shiga Toxin (AB toxin)
what is the role of the Shiga Toxin (AB toxin)
the receptor for B subunit is on kidney cells
A subunit inactivates ribosomes
=results in reduced anemia and kidney failure
how does E. coli O:157 spread
associated initially with ground beef
spreading maure on crops now means O:157 outbreaks can happen in green leafy veggies
what are the food safety regulations
keep food out of danger zone: 4.4 and 60 C
cook beef to internal temp 60F/71.1C
what are the characteristics of Staphylococcus aureus
gram positive bacteria on skin, respiratory tract and vagina
what are some common diseases from S. aureus
food poisoning
skin infections
toxic shock syndrome
what are some characteristics of S. aureus food poisoning
probs the most common FP
it is intoxication
causes vomiting an diarrhea
what is the virulence factor of S. aureus food poisoning
enterotoxin
what is the SpA protein
it binds to Fc region of antibodies and prevents phagocytosis
binds to Bcell receptors and causes cell death
what are some common skin infections caused by S. aureus
Impetigo: crusty lesions on face
Carbuncle: abcesses
what is TSS
when absorbant tampons create an environment with increased oxygen levels , results in TSST1
symptoms of TSS
high fever
low blood pressure
rash
what are some characteristics of Salmonella typhi
“typhoid fever”
gram negative
aquired from contaminated food or water
what is the virulence of Salmonella typhi
T3SS and AB toxin
what does S. typhi result in
a severe systemic disease
-fever, chills, headache, muscle pain
what are carriers of S. typhi
when people recover from Typhoid but continue to be colonized, it can persist within the gall bladder
