Infection of Skin, Soft Tissue, Muscle, and Associated Systems Flashcards
Most common skin flora
Staphylococcus epidermidis
What are Langerhans cells?
Dendritic cells in the epidermis
Is S. epidermidis gram positive or negative? Catalase positive or negative?
Gram positive
Catalase positive
What is toxemia?
Bacterial infections release skin-damaging toxins through the blood
What is a macule?
Flat, red: Local inflammation immune response infiltrating leukocytes
What is a papule?
Raised, red: More marked inflammation (invasion of neighbouring tissue)
What is a vesicle?
Small blister (pus): Microbes invades epithelium (HSV, VZV)
What is an ulcer?
Epithelium ruptures, microbe discharged
What is a papilloma?
Microbe grows in epithelium which proliferates; microbes shed with epithelial cells (wart)
What is the difference between petechiae and purpura?
Petechiae is smaller skin bleeding
Purpura is larger skin bleeding
What are the properties of Staphylococcus aureus?
Gram positive Beta-hemolysis Gold colonies Catalase positive Coagulase positive
What does hemolysin do?
Lyses red blood cells
What is the difference between beta and alpha hemolysis?
Beta: complete destruction of the cell
Alpha: only partial destruction of the cells
What is a furuncle and a carbuncle?
Furuncle is a boil or deep folliculitis
Carbuncle is large fusion of many furuncles
What does staphylococcal exfoliative toxin (exfoliatin) do?
Digests cadherins in desmosomes causing the skin just below stratum granulosum to split
