If the genetic material were isolated and injected into the cytoplasm of a human cell, which of the following would produce viable, infectious virions?
ALassa fever virus
BRabies virus
CRhinovirus
DMumps virus
EInfluenza virus
A team of intensivists working in a private intensive care unit (ICU) observe that the clinical efficacy of vancomycin is low, and proven nosocomial infections have increased progressively over the past year. A clinical microbiologist is invited to conduct a bacteriological audit of the ICU. He analyzes the microbiological reports of all patients treated with vancomycin over the last 2 years and takes relevant samples from the ICU for culture and antibiotic sensitivity analysis. The audit concludes that there is an increased incidence of vancomycin-resistant Enterococcus fecalis infections. Which of the following mechanisms best explains the changes that took place in the bacteria?
ADecreased number of porins in the bacterial cell wall leading to decreased intracellular entry of the antibiotic
BProduction of an enzyme that hydrolyzes the antibiotic
CProtection of the antibiotic-binding site by Qnr protein
DIncreased expression of efflux pumps which extrude the antibiotic from the bacterial cell
EReplacement of the terminal D-Ala in the cell wall peptidoglycan by D-lactate
An 18-year old college freshman presents to his university clinic because he has not been feeling well for the past two weeks. He has had a persistent headache, occasional cough, and chills without rigors. The patient’s vital signs are normal and physical exam is unremarkable. His radiograph shows patchy interstitial lung infiltrates and he is diagnosed with atypical pneumonia. The patient is prescribed azithromycin and takes his medication as instructed. Despite adherence to his drug regimen, he returns to the clinic one week later because his symptoms have not improved. The organism responsible for this infection is likely resistant to azithromycin through which mechanism?
AMutation in topoisomerase II
BMethylation of ribosomal binding site
CPresence of a beta-lactamase
DDecreased binding to RNA polymerase
EInsertion of drug efflux pumps
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