SESIÓN 09 STAPHYLOCOCCUS Y COCOS GRAM POSITIVOS RELACIONADOS. Flashcards
•Mencionará la clasificación de las especies de importancia médica. •Mencionará las características fisiológicas y estructurales. •Describirá los factores de virulencia que intervienen en la patogenia e inmunidad. •Mencionará los aspectos epidemiológicos.
What type of bacteria are staphylococci?
G (+) cocci that grow in patterns that resemble clusters of grapes.
What are the medically relevant species of Staphlylococcus?
SALE: S. saprophyticus, S. aureus, S. lugdunensis, S. epidermidis
What is special about S. aureus that separate it from other staph species?
Only species in human body that produces coagulase (coagulase-postive staphylococcus)
What serotypes of S. aureus are associated with with the majority of infections in humans?
Serotypes 5 and 7.
What is in the surface of S. aureus strains that coagulase-negative staphlycocci don’t have and what does it do?
.
Protein A. Inhibitis antibody-mediated clearance by binding IgG1, 2, and 4 Fc receptors; leukocyte chemoattractant; anticomplementary
What are the toxins that S. aureus produces? (16)
5 cytolitic, 2 exfoliative, 8 enterotoxins, and toxic shock syndrome-1.
Which cytotoxin of S. aureus is responsible for disease in humans and animals?
Beta toxin (aka sphingomyelinase C). Heat liable protein.
What do the exfoliative toxins of S. aureus do that are important diagnostic tools?
Serine proteasese that split the intercellular bridges in the stratum granulosum epidermis. The toxins are not associated w/ cytolysis or inflammation, so neither staphylococci nor leukocytes are typically present in the involved layer of the epidermis.
Which staphylococcal enterotoxin is most commonly associated with food poisoning?
Enterotoxin A
Which staphylococcal enterotoxin is most commonly associated with contaminated milk products?
Enterotoxin C and D
Which staphylococcal enterotoxin is most commonly associated with pseudomembranous enterocolitis?
Enterotoxin B
