The surgical equipment used during a craniectomy is sterilized using pressurized steam at 121°C for 15 minutes. Reuse of these instruments can cause transmission of which of the following pathogens?
ANon-enveloped viruses
BSporulating bacteria
CPrions
DEnveloped viruses
EYeasts
An 8-year-old girl is brought to the emergency room for a 6-hour history of fever, sore throat, and difficulty swallowing. Physical examination shows pooling of oral secretions and inspiratory stridor. Lateral x-ray of the neck shows thickening of the epiglottis and aryepiglottic folds. Throat culture with chocolate agar shows small, gram-negative coccobacilli. The patient's brother is started on the recommended antibiotic for chemoprophylaxis. Which of the following is the primary mechanism of action of this drug?
AInhibition of the 50S ribosomal subunit
BInhibition of prokaryotic topoisomerase II
CInhibition of DNA-dependent RNA-polymerase
DInhibition of the 30S ribosomal subunit
EInhibition of peptidoglycan crosslinking
A stool sample was taken from a 19-year-old male who presented with profuse watery diarrhea. He recently returned from a trip to Central America. A microbiologist identified the causative agent as a gram-negative, oxidase-positive, comma-shaped bacteria that is able to grow well in a pH > 8. Which of the following is a mechanism of action of the toxin produced by this bacteria?
AOveractivation of adenylate cyclase by inhibition of Gi subunit by ADP-ribosylation
BInactivation of the 60S ribosomal subunit by cleaving an adenine from the 28S rRNA
COveractivation of guanylate cyclase
DOveractivation of adenylate cyclase by activation of Gs subunit by ADP-ribosylation
EDegradation of cell membranes by hydrolysis of the phospholipids
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