staph infections

Question 1

before answering this question draw the diagram for the gram positive bacteria

where is staph aureus usually found
what is the associated pigment
and what type of hemolysis is associated ?

Answer 1

normally found in the nose
yellow pigment
beta hemolytic

Question 2

what is the virulence factor for staph aureus ?

Answer 2

protein A
binds Fc portion of the IgG antibody
has a lipid a core
antigen O

Question 3

what are the toxin associated disease staph aureus ?

Answer 3

TSS toxic shock syndrome (TSST-1)
food poisoning ( staph enterotoxin )
scalded skin syndrome

Question 4

what toxin is associated with scalded skin syndrome ?

Answer 4

exfoliative toxin

Question 5

how would you be able to tell the difference between sepsis and toxic shock syndrome ?

Answer 5

resembles a sunburn may be associated with diarrhea and associated with desquamation

Question 6

what is the classic scenario of staph food poisoning ?

Answer 6

food left in the sun for a long time
usually associated with potato or egg salads

Question 7

what is the classic presentation of scalded skin syndrome ?

Answer 7

associated with newborns
positive nikolsky sign

Question 8

what is the mechanism associated with scalded skin syndrome ?

Answer 8

staph aureus exfoliative toxin
only damages the keratinocytes in stratum granulosum

Question 9

what is the causative organism in bullous impetigo vs impetigo ?

Answer 9

bullous - staph aureus
impetigo - group A Strep

Question 10

what is the causative organism in subacute vs acute endocarditis ?

Answer 10

subacute - strep viridans needs prior valve abnormality
acute - staph aureus

Question 11

what is the best prevention for staph bacteremia ?

Answer 11

proper sterile techniques

Question 12

why are MRSA resistant to b lactams ?

Answer 12

they have altered penicillin binding proteins

Question 13

what is the treatment for MRSA ?

Answer 13

vancomycin or daptomycin

Question 14

where is staph epidermidis usually found ?

Answer 14

found in the normal skin flora

Question 15

what are the 2 main linical implications of staph epidermidis ?

Answer 15

blood culture contamination
infections of prosthetics

Question 16

what is the mechanism of infection that is assocated with staph epidermidis in prosthetics ?

Answer 16

allows for the formation of a biofilm

Question 17

what is the most common cause of honeymoon cystitis ?

Answer 17

staph saprophyticus

Question 18

which bacteria that cause UTI are associated with negative nitrites ?

Answer 18

enterococcus and staph saprophyticus

Question 19

what antibiotic is used for the mtreatment of UTI ?

Answer 19

fluroquinolones
nitfurantoin

Question 20

what is the classic cause of osteomyelitis in children ?

Answer 20

staph aureus

Question 21

what is the classic cause of osteomyeloitis in sickle cell anemia patients ?

Answer 21

salmonella

Question 22

what is the classic cause of osteomyelitis in TB patients ?

Answer 22

potts disese

Question 23

what layers of the skin are affected by cellulitis ?

Answer 23

infection of the deep dermis and subcutaneous fat

Question 24

what gene is responsible for the MRSA resistant factor ?

Answer 24

mecA gene

Question 25

what is the virulence factor associated with community acquired MRSA ?

Answer 25

PVL

Question 26

how would you differentiate between staph aureus and staph apidermidis in lab testing ?

Answer 26

s aures ferments mannitol whilst epidermidis doesnt

Question 27

what type of immune response is associated with the TSST toxibnn ?

Answer 27

binds to MHC II and T cell receptor resulting in polycloonl t cell activation

Question 28

what colour msputum is associated nwith pneumococcal pneumonia ?

Answer 28

rusty sputum