A 62-year-old woman presents to the emergency department for evaluation of a spreading skin infection that began from an ulcer on her foot. The patient has type 2 diabetes mellitus that is poorly controlled. On examination, there is redness and erythema to the lower limb with skin breakdown along an extensive portion of the leg. The patient’s tissues separate readily from the fascial plane, prompting a diagnosis of necrotizing fasciitis. What is the exotoxin most likely associated with this patient’s presentation?
AStreptococcal pyogenic exotoxin A
BTSST-1
CDiphtheria toxin
DExfoliative toxin
EStreptococcal pyogenic exotoxin B
A 4-year-old boy is presented to the clinic by his mother due to a peeling erythematous rash on his face, back, and buttocks which started this morning. Two days ago, the patient’s mother says his skin was extremely tender and within 24 hours progressed to desquamation. She also says that, for the past few weeks, he was very irritable and cried more than usual during diaper changes. The patient is up to date on his vaccinations and has been meeting all developmental milestones. No significant family history. On physical examination, the temperature is 38.4°C (101.1°F) and the pulse is 70/min. The epidermis separates from the dermis by gentle lateral stroking of the skin. Systemic antibiotics are prescribed, and adequate fluid replacement is provided. Which of the following microorganisms most likely caused this patient’s condition?
AClostridium sp.
BStaphylococcus aureus
CNeisseria meningitidis
DBacillus anthracis
EStreptococcus sp.
A 69-year-old woman is brought to the emergency department by her husband because of a 1-day history of fever, shortness of breath, dizziness, and cough productive of purulent sputum. Six days ago, she developed malaise, headache, sore throat, and myalgias that improved initially. Her temperature is 39.3°C (102.7°F) and blood pressure is 84/56 mm Hg. Examination shows an erythematous, desquamating rash of the distal extremities. A sputum culture grows gram-positive, coagulase-positive cocci in clusters. The most likely causal organism of this patient's current symptoms produces a virulence factor with which of the following functions?
ABinding of Fc domain of immunoglobulin G
BInactivation of elongation factor 2
COverstimulation of guanylate cyclase
DDestruction of immunoglobulin A
EDegradation of membranous phospholipids
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