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 65-year-old man presents with low-grade fever and malaise for the last 4 months. He also says he has lost 9 kg (20 lb) during this period and suffers from extreme fatigue. Past medical history is significant for a mitral valve replacement 5 years ago. His temperature is 38.1°C (100.6°F), respirations are 22/min, pulse is 102/min, and blood pressure is 138/78 mm Hg. On physical examination, there is a new onset 2/6 holosystolic murmur loudest in the apical area of the precordium. Which of the following organisms is the most likely cause of this patient’s condition?
AEnterococcus
BCandida albicans
CCoagulase-negative Staphylococcus spp.
DEscherichia coli
EPseudomonas aeruginosa
A microbiology student was given a swab containing an unknown bacteria taken from the wound of a soldier and asked to identify the causative agent. She determined that the bacteria was a gram-positive, spore-forming bacilli, but had difficulty narrowing it down to the specific bacteria. The next test she performed was the Nagler's test, in which she grew the bacteria on a plate made from egg yolk, which would demonstrate the ability of the bacteria to hydrolyze phospholipids and produce an area of opacity. Half the plate contained a specific antitoxin which prevented hydrolysis of phospholipids while the other half did not contain any antitoxin. The bacteria produced an area of opacity only on half of the plate containing no antitoxin. Which of the following toxins was the antitoxin targeting?
AAlpha toxin
BExotoxin A
CTetanus toxin
DDiphtheria toxin
EBotulinum toxin
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