STAPH Flashcards
What kind of pathogen is staphylococcus?
bacteria
Is staph gram positive or gram negative?
Gram positive
What would Staph look like on a microscope slide?
Purple stained grapelike clusters (cocci)
What is the portal of entry for staph into the body?
Skin
What are the five strains of staph we are focusing on in ID?
-Staph epidermis
-Staph aureus
-Staph saprophyticus
-MSSA (Methicillin Sensitive Staph aureus)
-MRSA (Methicillin Resistant Staph aureus)
What is the epidemiology/distribution of Staph epidermis?
human skin (colonizes here naturally!)
How does Staph epidermis infect the host (pathogenesis)?
Usually will infect foreign materials like catheters/IV’s/shunts
How does a Staph epidermis infection present?
Not likely to infect wounds, but will have an infection in the places of foreign objects like artificial joints, central lines, catheters
(Pneumonic: you inject an EPI pen and it will break the skin, EPIdermis is caused by foreign objects that enter skin like catheters/IV’s)
What test would you use to determine an infection may be caused by Staph epidermis? What would the result be?
Coagulase test, result would be negative
What is coagulase? What is a coagulase test?
Coagulase: an enzyme produced by certain bacteria which will coagulate (clump/solidify) plasma/blood
Coagulase test: bacterial sample will be used on test media (if a clump is present=coagulase positive, if still liquid=coagulase negative)
What is the treatment for a Staph epidermis infection?
-Empiric treatment usually IV Vancomycin for 7 days (if infection invasive)
-Remove any foreign material infected by the bacteria
-Often will be resistant to beta-lactam antibiotics like penicillin, but if susceptible, may use these
What is the epidemiology/distribution of Staph aureus?
Moist areas (like nasal)
*can tansmit/be spread to other areas/wounds
30% of people are carriers of S. aureus
How does Staph aureus infect its host (pathogenesis)?
-It will infect blood, skin, wounds, joints, and the respiratory tract
-Suppurative disease (will cause/produce pus)
-Toxin mediated, s.aureus will produce toxins (toxins can be transmitted in food): food poisoning, toxic shock, scalded skin syndrome, etc.
What is the presentation of a Staph aureus infection?
TSS: Toxic Shock Syndrome: toxin is released and will cause a generalized skin reaction, could result in shock
SSS: Scalded Skin Syndrome: Top layer os the skin may peel off (Niloski sign), and release toxin (can happen in infants-infected umbilical stump)
-Suppurative infection: pus may be present in skin, mouth, and really can occur anywhere
-Tissue damage may occur
Staph aureus is very pathogenic!!!
How would you diagnose a Staph aureus infection with tests?
-Culture the affected area (wound)
-Perform a coagulase test (positive!)
