Question #12 explained:
HG is a 64 year-old female who presents to her primary care doctor with complaints of dysuria and increased urinary frequency. She has a past medical history that includes osteoporosis. She has a sulfa allergy. She is post-menopausal. Due to the low-grade symptoms she is experiencing, the provider orders a urine culture with urinalysis, then tells the patient to increase her water intake and call if symptoms worsen. Two days later the results of the urine culture are back and show E. coli that is sensitive to all drugs it was tested against (see below). The urinalysis is positive for leukocyte esterase, has 9 RBCs and has 155 WBCs. The provider calls the patient and despite increasing water intake the symptoms have persisted. Which of the following would be the best drug to give to this patient?
E. coli sensitive to: amoxicillin-clavulanic acid, piperacillin-tazobactam, cephalexin, ceftriaxone, cefepime, ciprofloxacin, sulfamethoxazole-trimethoprim, nitrofurantoin, and tobramycin
A. Nitrofurantoin CORRECT
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- Nitrofurantoin shows as active against the organism, it is a lower UTI, the patient does not have any indication of renal impairment, and nitrofurantoin is widely considered a first-line agent for UTI. It is the best option for this patient.
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B. Sulfamethoxazole-trimethoprim
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- Due to the sulfa allergy, SMX-TMP should be avoided.
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C. Ampicillin
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- While the organism is sensitive to all listed drugs, sensitivity to ampicillin is not listed. Since there are options with known sensitivity, it is inappropriate to pick ampicillin for this patient. Sometimes resistance or sensitivity can be predicted based upon reported results. If sensitivity to amoxicillin were supplied, then ampicillin could have been selected.
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D. Ciprofloxacin
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- Due to the toxicities (e.g., tendon rupture, peripheral neuropathy) and collateral damage (i.e., induction of resistance within a variety of organisms and association with Clostridium difficile infection), fluoroquinolones should not be used first-line for uncomplicated UTI such as cystitis. While ciprofloxacin may work, it should be avoided in this scenario.
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