A 70-year-old woman is brought to the emergency department due to persistent fever and increase confusion. The patient has a history of Alzheimer dementia and lives in a nursing home. Temperature is 38.4 C (101.1 F), blood pressure is 104/74 mm Hg, pulse is 110/min, and respirations are 18/min. Suprapubic tenderness is present on physical examination. Urinalysis shows numerous bacteria and leukocytes, and urine culture grows Pseudomonas aeruginosa. Further analysis reveals that the isolated organism produces an enzyme that is located on the cytoplasmic surface of the cell membrane and that catalyzes the transfer of acetyl groups to exogenous substances. The bacteria are most likely resistant to which of the following antibiotics?

Question

A 70-year-old woman is brought to the emergency department due to persistent fever and increase confusion.  The patient has a history of Alzheimer dementia and lives in a nursing home.  Temperature is 38.4 C (101.1 F), blood pressure is 104/74 mm Hg, pulse is 110/min, and respirations are 18/min.  Suprapubic tenderness is present on physical examination.  Urinalysis shows numerous bacteria and leukocytes, and urine culture grows Pseudomonas aeruginosa.  Further analysis reveals that the isolated organism produces an enzyme that is located on the cytoplasmic surface of the cell membrane and that catalyzes the transfer of acetyl groups to exogenous substances.  The bacteria are most likely resistant to which of the following antibiotics?

Quizplus · Accepted Answer

Eductional Objective: Pseudomonas aeruginosa is a gram-negative, opportunistic pathogen with multiple mechanisms of antibiotic resistance, including beta-lactamases, efflux pumps, and antibiotic-modifying enzymes. Antibiotic-modifying enzymes add chemical groups (eg, acetyl, adenyl, phosphate) to a target drug and are the most common mechanisms of aminoglycoside (eg, gentamicin) resistance. Altered aminoglycosides have a reduced ability to bind to the 16S ribosomal RNA within the 30S ribosomal subunit, leading to increased minimum inhibitory concentrations and reduced bactericidal effects. Most antibiotic-modifying enzymes arise via transfer of plasmids or transposons rather than chromosomal mutations.

A 70-Year-Old Woman Is Brought to the Emergency Department Due