Bacterial I - Morgan's Qs

Question 1

CA-MRSA virulence factor

Answer 1

panton-valentine leukocidin

Question 2

If pt is resistant to erythromycin, what other antibiotic should you also check with the D-test

Answer 2

clindamycin

Question 3

name for superficial bacterial folliculitis and MCC

Answer 3

Bockhart’s impetigo

MCC: staph aureus

Question 4

T/F: one way to distinguish sycosis vulgaris from tinea barbae is that it affects the upper lip

Answer 4

true: tinea barbae rarely affects upper lip

Question 5

what are the defects (AD & AR) of Job syndrome? what Ig levels will be elevated and depressed?

Answer 5

AD: STAT3 (regulates osteoclast activity)
AR: DOCK8 (seen w/ viral infections)
IgE increases, IgD decreases

Question 6

what are the defects (XLR & AR) for chronic granulomatous ds

Answer 6

XLR: gp91-phox
AR: p67-phox
defect in NADPHX oxidase enzyme complex –> inability to produce respiratory burst –> defective killing of catalase positive organisms

Question 7

causitive agent in chronic pyogenic paronychia

Answer 7

candida

Question 8

causative agent of abscess formation in pyogenic paronychia? erythema and swelling?

Answer 8

abscess formation: staph aureus

erythema & swelling: strep pyogenes

Question 9

MCC botryomycosis? sinuses discharge?

Answer 9

staph aureus

sulfur granules

Question 10

pyomyositis… MC site in children in tropics? MC site in temperate areas in immunosuppressed?

Answer 10

kids in tropics: thigh

immunosuppressed in temperate: deltoid, quad

Question 11

cause of acute glomerulonephritis in impetigo

Answer 11

strep pyogenes M type 2, 49, 55, 57, 60

Question 12

bullous impetigo site in kids? in adults? what causes extracellular cleavage of Dsg1?
T/F culture is positive for bullae.

Answer 12

kids: face and hands
adults: axillae and groin
cleavage of Dsg1: staph aureus exfoliative toxins A & B group 2 phage types 55 & 71
true - culture positive

Question 13

toxin in SSSS? where do you culture? what do you see in adults? T/F: SSSS affects palms/soles, mucous membranes.

Answer 13

toxin: exfoliative toxins A & B group 2 phage types 55 & 71
culture: conjunctiva, nasopharynx, feces, pyogenic foci
adults: immunosuppression, renal ds
false: does not affect palms/soles or mm

Question 14

cause of staph toxic shock syndrome? acute systemic symptoms?

Answer 14

exotoxin TSST-1 superantigen
acute febrile illness with pharyngitis, scarlatiniform exanthem first on trunk, erythema of palms and soles with desquamation

Question 15

cause of strep toxic shock syndrome? MC initial symptoms?

Answer 15

M types 1 & 3 produce exotoxins A, B, C

initial sxs: severe local pain in extremity

Question 16

toxic shock syndrome superantigen binding site? causes release of what cytokines?

Answer 16

binds to V-beta region on T-cells

stimulates T cell release of TNF-alpha, IL-1, IL-6, TLR 2 & 4

Question 17

T/F: scarlatiniform eruption is more common in strep TSS than staph TSS

Answer 17

False

scarlatiniform eruption more common in staph

Question 18

cause of ecthyma? initial morphology of the lesion? cause in HIV/IVDA pts?

Answer 18

cause: strep pyogenes
start as vesiculopustule –> crust –> saucer-sharped ulcer with raw base and elevated edges on shins/dorsal feet
cause in HIV/IVDA: staph aureus

Question 19

cause of scarlet fever? where does blanchable erythema start?
T/F: the palms and soles peel 2 wks after illness for up to 6 wks

Answer 19

cause: strep pyogenes types A, B, & C
neck –> chest & axillae –> trunk –> extremities
true

Question 20

staph scarlatina refers to?

Answer 20

mimic of scarlet fever except no strawberry tongue

Question 21

Job syndrome major findings

Answer 21

deficient neutrophil chemotaxis - cold abscesses, cellulitis, carbuncles, eczematous dermatitis, pneumatoceles, bronchitis

Question 22

major findings of chronic granulomatous disease

Answer 22

recurrent pyoderma, perioral dermatitis, lymphadenopathy, pneumonia with abscesses, empyema, osteomyelitis (serratia marcescens)

Question 23

Schultz-Carlton phenomenon

Answer 23

blanching erythema secondary to exotoxin

Question 24

bacteria that causes scarlatiniform exanthem and pharyngitis in young adults

Answer 24

Arcanobacterium haemolyticum

Question 25

cause of erysipelas? lab abnormalities? predisposing factors?

Answer 25

strep pyogenes leukocytosis >20,000 venous insufficiency, lymphedema

Question 26

three types of necrotizing fasciitis

Answer 26

I - polymicrobial II - strep pyogenes III - clostridial myonecrosis or gas gangrene

Question 27

progression of colors in necrotizing fasciitis

Answer 27

red-purple-gray-blue

Question 28

Meleney's gangrene is a complication of

Answer 28

surgical trauma

Question 29

MCC blistering distal dactylitis? can you culture

Answer 29

``` strep pyogenes (occ staph aureus) blister fluid of volar fat pad can be cultured ```

Question 30

cause of perianal dermatitis? in neonates?

Answer 30

``` strep pyogenes (occ staph aureus) neonates: group b strep ```

Question 31

Jones criteria: 2 skin signs and 3 other signs

Answer 31

skin: subcutaneous nodules & erythema marginatum other: polyarthritis, carditis, chorea

Question 32

fish pathogen causing cellulitis of hands

Answer 32

strep iniae

Question 33

cause of erysipeloid of Rosenbach

Answer 33

erysipelothrix rhusiopathiae

Question 34

erysipeloid purplish swelling of the hands involves the __ but spares the __

Answer 34

involves finger webs, spares phalanges

Question 35

pediatric presentation of pneumococcal cellulitis? in IVDA/DM pts?

Answer 35

peds: facial and periorbital edema and cellulitis IVDA/DM: extremity see fever, leukocytosis, septicemia

Question 36

in anthrax, what inhibits phagocytosis? | T/F: abx therapy does not alter progression from painless carbuncle --> vesicle --> ulcer --> eschar

Answer 36

polyclutamic acid capsule | true, progression not altered

Question 37

anthrax exotoxins and affects

Answer 37

``` edema toxin (edema factor + protective antigen): increases cAMP levels lethal toxin (lethal factor + protective antigen): release of TNF-alpha and IL1-beta ```

Question 38

treatment of listeria

Answer 38

ampicillin or bactrim

Question 39

name of ulcer caused by corynebacterium diptheria? what must be ruled out before giving IM antitoxin

Answer 39

ecthyma dipthericum | must rule out hypersensitivity to horse serum via conjuctival test first

Question 40

3 infections caused by cornyebacterium

Answer 40

erythrasma = cornyebacterium minutissimum pitted keratolysis = kytococcus sedentarius trichomycosis axillaris = cornyebacterium tenuis

Question 41

what causes coral red fluorescence in erythrasma

Answer 41

coproporphyrin III (woods lamp 365 nm)

Question 42

kytococcus sedentarius release __ that destroy the stratum corneum

Answer 42

serine proteases K1 and K2 in pitted keratolysis

Question 43

color produced with woods lamp on trichomycosis axillaris

Answer 43

pale yellow

Question 44

two membrane toxins produced by clostridium perfringens in gas gangrene? lab abnormalities?

Answer 44

``` alpha toxin (like sphingomyelinase) and perfringolysin leukocytosis and hemolytic anemia ```

Question 45

cause of tropical ulcer/jungle rot

Answer 45

bacteroides vincentii

Question 46

cause of desert sore in Australia with grouped vesicles --> rupture into ulcers on shins and knees

Answer 46

corynebacterium diphtheriae, staph and strep

Question 47

MC location of actinomyces israelii

Answer 47

cervicofacial - lumpy jaw caused by sulfur granules

Question 48

DOC for actinomyces israelii

Answer 48

penicillin G

Question 49

T/F: norcardia asteroides is most commonly caused by pulm ds that disseminates. cutaneous form caused by what species? DOC?

Answer 49

true nocardia brasiliensis bactrim