A 54-year-old woman comes to the physician because of lower back pain, night sweats, and a 5-kg (11-lb) weight loss during the past 4 weeks. She has rheumatoid arthritis treated with adalimumab. Her temperature is 38°C (100.4°F). Physical examination shows tenderness over the T10 and L1 spinous processes. Passive extension of the right hip causes pain in the right lower quadrant. The patient's symptoms are most likely caused by an organism with which of the following virulence factors?
AProteins that bind to the Fc region of immunoglobulin G
BProtease that cleaves immunoglobulin A
CPolysaccharide capsule that prevents phagocytosis
DSurface glycolipids that prevent phagolysosome fusion
EPolypeptides that inactivate elongation factor 2
A 68-year-old man comes to the physician because of headache, fatigue, and nonproductive cough for 1 week. He appears pale. Pulmonary examination shows no abnormalities. Laboratory studies show a hemoglobin concentration of 9.5 g/dL and an elevated serum lactate dehydrogenase concentration. A peripheral blood smear shows normal red blood cells that are clumped together. Results of cold agglutinin titer testing show a 4-fold elevation above normal. An x-ray of the chest shows diffuse, patchy infiltrates bilaterally. Treatment is begun with an antibiotic that is also used to promote gut motility. Which of the following is the primary mechanism of action of this drug?
AInhibition of bacterial RNA polymerase
BInhibition of folic acid synthesis
CFree radical creation within bacterial cells
DInhibition of transpeptidase cross-linking at the cell wall
EInhibition of peptide translocation at the 50S ribosomal subunit
An investigator is studying the chemical structure of antibiotics and its effect on bacterial growth. He has synthesized a simple beta-lactam antibiotic and has added a bulky side chain to the molecule that inhibits the access of bacterial enzymes to the beta-lactam ring. The synthesized drug will most likely be appropriate for the treatment of which of the following conditions?
AFolliculitis
BNocardiosis
CAtypical pneumonia
DErythema migrans
EOtitis media
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