staph stre Flashcards
most common cause of septic abortion
staph aureus
function of hyaluronidase
digest extracellular ground substance and enhance their ability to spread
hylaurinodiase used by
s. auerus, s pyogens, c. perfringens
suppurative parotitis in adults is what
acute viral or bacterial infection of parotid gland
firm erythematous pre/postauricular swelling: extends to mandible; elevated amylaee
most common cause of suppurative parotitis
Staph aureus(can also be cauesd by anaerobes)
a superantigen that binds to MHC II and T cell receptor resulting in polyclonal activation. also interacts w macs
TSST
coagulase + cocci in clusters
staph auerus
Function of staph aureus Protein A
virulence factor; binds Fc-IgG, inhibit complement activation and phagocytosis; prevents oposonization
commonly colonizes anterior nares, axilla, groin
staph auerus
Staph auerus is what color pigment
golden-yellow pigment
staph auerus causes
skin infections, organ abscesses, pneumonia (often after influenza virus infection). skin + soft tissue abscess
staph auerus heart
right sided endocaridtis (IV)
most common cause of staph auerus
septic arthritis, osteomyelitis
staph auerus enterotoxin
rapid food poisioning: think precooled foods, dairy products, custards, mayonnaise based salads (chicken salads; preformed, heat stable ennterotoxin
Scalded skin syndrome: what toxin
exfoliative exotoxin; acts as proteases and cleaves desmoglein in desmosomes
What is nikolsky’s sign and where is it seen
Nikolsky’s sign (SSS) (skin slipped off w gentle pressure, epidermal necrolysis, fever, pain assoc w skin rash)
fever, vomiting, rash, desqumation, shock, end organ failure. increase AST, ALT, bilirubin
Toxic shock syndrome
how do staph and strep pyogenes TSS are different
strep pyogenes TSS assoc w painful skin infection
Staph aureus enterotoxin is not destroyed by cookign. this means it is
heat stable. also is a preformed toxin
abscess caused by staph auerus : explain
forms fibrin clot around self
how is tracheitis different than epiglottis
similar but no swollen epiglotis; this is caused by staph auerus
S. auerus spreads
hematogenously
R sided endocarditis sends emboli to
lung
for staph aeurus why are recurrent infections common
bc oral antbiiotics do not eliminate colonization of nares + skin
how are s. auerus and s. epidermidis different (think fermentation
s. auerus is a mannitol f ermenter
Infects prosthetic devices (hip implant, heart valve) and IV catheters by producing adherent biofilms
Staph epidermidis
most common cause of endocartitis in pt’s w prostehetic valves and also septic arthrisit in pt’s with prostehteic joints
staph epidermidis
Staph epidermidis is in the nnormal flora of the
skin
once introduced into body, foreign bodies become coated w layer of host proteins, including fibrinogen and fibronectin. serve as binding site for
s. epidermidis
after attachment of s. epidermidis occurs; bacteria multiply and communicate to induce syntehsis of
extracellular polysaccharide matrix
biofilm does what
barrier to antiboitioc penetration and host defenses
infects foreign bodies * ; contaminates blood cultures
s. epidermidids
ventriculoperitoneal shutns
s. epidermidis (also is ureas +, cocci in clusters
what is MRSA
methicillin resistant S . auerus: impto cause of serious nosocomial and community acquired infectiosn
why are MRSA resistant to methicillin and nafcillin
because of altered penicillin binding protien
all staph are cocci in clusters
true
S. saprophyticus. is in the normal flora of
female genital tract and perineum
2nd most common cause of uncomplicated UTI in young women
S. saprophyticus (urease +)
gram + lancet shaped diplococci in pairs
strep pneumoniae
MOBS: strep pneumonia most common cause
meningitis
otitis media (in children)
bacterial pneumonia
sinusitis
most common cause of community acquired pneumonia in both HIV infected and HIV uninfected individulas
s. pneumoniae
what are virulence factors for strep pneumoniae
adhesins (adhesion to epithelial cells)
pneumolysin (cytotoxin that causes pores in cell membranes and cell lysis
IgA protease
encapsulated
describe strep capsule
thick polysaccharide: encases organisms and prevent phagocytosis + complement binding
pneumococcus associated with
rusty sputum, sepsis in pt’s w sickle cell disease, asplenic pt’s
is there a pneumococcal vaccine
yes; against capsule
quellung reaction is
S. pneumonia capsule swells and appears as halo around blue srand bacterial cells when anti capuslar antiboides and methylene blue dye are added
normal flora of oropharynx
Viridans group streptococci
Viridans includes
Strep mutans, S. mitis. S. sanguinis
which viridans cause dental caries
strep mutans and mitis
subacute bacterial endocaritis at damaged heart valves
S. sanguinis
what do s. sanguinis makes: these bind to fibrin platelet aggregates on damaged heart valves
dextrans
insoulble extracellular polysaccharides that use sucrose as substrate that adhere to
dextrans adhere to both enameland fibrin platelt aggregates
n. meningitiids colonizes the
nasopharynx.; goes through bloodstream
pyogenic- pharyngitis, cellulitis, impetigo (honey crusted lesions, erysipelas
strep pyogenes
toxigenic: scarlet fever, TSST, necrotizing fasciitis
strep pyogenesi
strep pyogenic immunolicagl cause
rheumatic fever, glomerulonephritis (PSGN)
which s. pyogenes capule inhibits phagocytosis
hyaluronic acid capsule
antbiodies to M protine enhance host defenses against S. pyogenes butc ccan vgive rise to
can give rise to rheumatic fever
you see acute rheumatic fever after GAS pharynigits or GAS skin infection
GAS pharyngitis
you see glomerulonephritis after GAS skin infection
what does s. pyogenes bind to
factor H: prevents opsoniziation
pyrogenic extoxin acts as a
superantigen; inducing fever and shock; assoc w scarlet fever; strep tTSS
M protein is an alpha helicalc coiled coli protein that shares structural homology w
other coiled protiens such as tropomyosin and myosin
antigen mimicry
antibodies against M protein in cuate infection may cross recat with epiptopes of mysoni ion heart = rheumatic carditis
blanching, sandpaper like body rash, strawberry tongue, circumoral pallor
scarlet fever: erythrogenic toxin +
you see ASO titer or anti dNase B antibodies in
recent S. pyogenes infection
Group B strep is for
BaBIES
group b strep (strep agalactiase) causes what in babies
pnuemona, sepsis, meningits
produces CAMP factor
strep agalactiase
purpose of CAMP factor
enlarges area of hemolysis for s. auerus
universal screening of pregnant women at 35-37 weeks for what
strep agalactiae
if you have a + culture during prennacy receive
intrapartum penicllin (or ampicilin) prophylaxis
is there a vaccine to strep agalacitae
NO
THIS COLONIZES THE GUT
S. bovis
S. gallolyticus (s. bovis type I) can cause
bacteremia and subacute endocarditis
colon cancer
s bovis
why is s. bovis endocardiits unique
no preexisting valuvlar abnomralite
what differenteiates non enteroccoucs and neteroccocus
enteroccous is PYR +
PYR stands for
pyrrolidonyl arylamidase
normal colonic flora that are penicllin G resistant
Enterococci
cause UTi, biliary tract infections, subactue endocarditis (following GI/GU procedures)
enterocci
variable hemolyssi
enterococci
what is VRE
vancomycin resistant enteroccoi: impt cause of noscomial infection
think of a recently undergone cystocopy or colonsocpy: endocarditis
enterocci (e. faecalis, and E. faecium
