Gram Positive Bacteria Flashcards
S.aureus is salt tolerant on?
Mannitol Salts Agar
Gram positive cocci in grape clusters
Staphylococcus aureus
S.aureus gold color is due to?
Staphyloxanthin
Common habitat of S.aureus
Anterior nares - and sometimes on skin
Virulence factor: prevents complement activation
Protein A
Virulence factor: detoxifies hydrogen peroxide
Catalase
Virulence factor: specific for white blood cells
PV Leukocidin
Virulence factor: builds an insoluble fibrin capsule
Coagulase
Virulence factor: inactivates penicillin derivatives
Penicillinase
Virulence factor: toxic to hematopoietic cells
Hemolysins - cytotoxins
Virulence factor: dissolved fibrin clots
Fibrinolysin - staphylokinase
Virulence factor: spread in fat containing areas of the body
Lipase
Virulence factor: causes SSSS
Exfoliatin - causes epidermal separation
Valve involve in IV drug abusers having acute endocarditis
Tricuspid valves
Virulence factor: superantigens causing food poisoning
Enterotoxins
Virulence factor: causes marked necrosis of the skin and hemolysis
Alpha toxin
Sequestered focus of osteomyelitis arising in the metaphyseal area of a long bone
Brodie abscess
Virulence factor: superantigen leading to toxic shock syndrome
Toxic shock syndrome toxin (TSST-1)
Scalded skin syndrome is also known as what diseae?
Ritter disease
With Ritter disease, exfoliatin cleaves the ____ in desmosomes
Desmoglein
With SSSS, separation of epidermis is at _____
Stratum granulosum
Disease entity where separation occurs at dermo-epidermal junction
TEN (Lyell disease)
Drug of choice for MRSA
Vancomycin
Drug of choice for VRSA
Linezolid
Also known as S.albus
Staphylococcus epidermidis. - positive catalase, coagulase negative, novobiocin sensitive
Patient came in with an infected prosthetic joints. What would be the possible organism on culture?
S.epidermidis - glycocalyx adheres well to foreign bodies and form biofilms
Condition that may show strawberry tongue:
Scarlet fever
Kawasaki disease
Toxic Shock syndrome
Second most common cause of UTIs in sexually active women
Staphylococcus saprophyticus
E.coli in the Philippines
Treatment of choice for S.saprophyticus infection
TMP-SMX, quinolones
Most common cause of bacterial pharyngitis
Streptococcus pyogenes - habitat: skin and oropharynx
Virulence enzyme: that degrades DNA in exudates or necrotic tissue
DNase (streptodornase)
Virulence enzyme: inactivates complement C5a
C5A peptidase
Toxin: that causes necrotizing fasciitis
Exotoxin B
Used for to document antecedent pharyngitis
Anti-Streptolysin O (ASO)
Titers to document antecedent skin infection
Anti-DNAse B
Most likely to progress or cause glomerulonephritis
Pyoderma
Pyogenic infection with perioral blistered lesions with honey-colored crust. Accumulation of neutrophils beneath stratum corneum.
Impetigo contagiosa - while Bullous impetigo is caused by S.aureus
Pyogenic superficial infection extending into dermal lymphatics, painful
Erysipelas
Pyogenic deeper infection involving subcutaneous/dermal tissues.
Cellulitis - facilitated by hyaluronidase
Pyogenic rapidly progressive infection of deep subcutaneous tissues facilitated by Exotoxin B
Necrotizing fascitis
Postpharyngitic due to erythrogenic toxin seen in lysogenized strains.
Scarlet Fever
Postpharyngitic cross-reacting antibodies to M proteins and antigens of joint, heart and brain tissues. Patient presents with pancarditis, erythema marginatum, Sydenham chorea and migratory polyarthritis
Acute Rheumatic Fever - due to molecular mimicry
Criteria used for Rheumatic fever
Jones Criteria
Polyarthritis, Chorea, Carditis, Subcutaneous nodules
M protein incites immune complex deposition on the glomerular basement membrane. SSX: hypertension, periorbital edema and hematuria
Glomerulonephritis - mc common is post-impetigo