w7 skin infections Flashcards
what are the 3 major genera of disease causing gram + cocci
staphylococcus
streptococcus
enterococcus
3 clinically significant straphylococcus species
staphylococcus aureus
staphylococcus epidermidis
staphylococcus saprophyticus
what infections can staphylococcus have
skin, soft tissues, bone, urinary tract
where is staph aureus commonly found
anterior nares (nostrils)
what does the capsule (rigid) in staphylococcus
inhibits phagocytosis by WBCs
what does the slime layer (loose) do in staphylococcus
facilitates adherence to tissues and foreign bodies such as catheters
what is the important of teichoic acid in staph
mediate ATTACHMENT to MUCOSAL surfaces by binding to fibronectin in ECM
(species specific [antigenic determinant] )
protein A present in what and function in staph
staph AUREUS , but not staph epidermis or staph saprophyticus
binds to Fc region of IgG, preventing ANTIBODY MEDIATED IMMUNE CLEARANCE
function and mechanism of clumping factor in staph species
binds fibrinogen and converts it to insoluble fibrin, causing staph to clump aggregate
protects microbe from being PHAGOCYTIZED by WBCS (WBCs penetrate fibrin clots poorly)
where is staph aureus mainly found
-anterior nares (nostrils)
-skin
-mucous membranes
where is staph epidermidis mainly found
skin
where is staph saprophyticus mainly found
-female genital tract
-perineum
what staph as a lot of viruelnce factors
staph auereus
what is the most virulent of the staphs, most common cause of bacterial infections, important cause of toxic shock syndrome
staph aureus
staph aureus virulence factors enzymes (6)
catalase (catalase +), coagulase, hyaluronidase (breaks down hyaluronic acid [spreading factor]), lipase, penicillinase (B-lactamase), penicillin-binding protein [transpeptidase])
treatment for community acquired-methicillin resistant staphylococcus aureus (CA-MRSA)
treatment for hospital acquired (HA-MRSA)
ciprofloxcain or clindamaycin
vancomycin
what is a common cause of catheter or prosthetic device infections
staph epidermis
what is part of the normal vaginal microbiota and an important cause of urinary tract infection (UTI)
staph saprophyticus
what produces a green pigment and has a fruity smell
pseudomonas aeruginosa
strep gram (- or +), catalse (- or +)
gram +
catalse -
what plate do you need to grow strep (bc they are fastidious)
blood agar plate (BAP)
most strep are what kinda for oxygen requirement
aerotolerant anaerobes (do not use oxygen but can tolerate it)
which hemolytic streptococci has a greenish zone around the colony
alpah-hemolytic
beta-hemolytic, alpha-hemolytic, gamma-hemolytic (non-hemolytic) strep RBC lyze status
beta - RBCs completely lyzed
alpha - RBCs incompletely lyzed
gamma - no action on RBCs
what is the most common type of strep. pyogenes (group A) infection
PHARYNGITIS (sore throat)
what causes scarlet fever (red skin rash on body)
S. pyogenes (group A)
what is impetigo and what causes it
S. pyogenes (group A)
localized superficial, spreading crusty skin lesion on face on children
symptoms of erysipelase and what causes it
S. pyrogenes
fiery red, advancing erytherma, esp on face or lower limb
symptoms of cellulitis and what causes it
appears red, hot, shiny, and swollen
S. pyogenes (group A)
symptoms of necrotizing faciitis and what causes it
group A (S. pyrogenes)
deep local invasion of the skin w necrosis (flesh eating disease)
rheumatic fever (rheumatic heart disease) symptoms and what causes it
following pharyngeal infection only
fever, rash, carditis, arthritis
s. pyogenes (group A)
acute glomerulonephritis symptoms and what causes it
group a (s .pyrogenes)
puffy face, darker urine, hypertension
peptostreptococci (anaerobic strep) causes what and found where
causes endometritis and lung abscesses
normal oral and vaginal flora
