A 28-year-old woman is evaluated in the hospital on the third day of admission for acute pyelonephritis. On admission, she presented with fever, chills, right-sided flank pain, and dysuria. She was started on empiric intravenous ceftriaxone. Today, she reports feeling much better and has been afebrile for the past 24 hours. Her right costovertebral angle tenderness has largely resolved. She is tolerating a regular diet.
Urine culture obtained on admission has grown > CFU/mL of *Klebsiella pneumoniae*. Antimicrobial susceptibility testing results are as follows:
| Antimicrobial | Interpretation |
|---|---|
| Ampicillin | Resistant |
| Cefazolin | Susceptible |
| Ceftriaxone | Susceptible |
| Ciprofloxacin | Susceptible |
| Nitrofurantoin | Susceptible |
| Trimethoprim-sulfamethoxazole | Susceptible |
Which of the following is the most appropriate next step in management?
- Transition to oral ciprofloxacinAnswer
- BTransition to oral nitrofurantoin
- CTransition to oral ampicillin
- DContinue intravenous ceftriaxone
- EAdd intravenous gentamicin
Answer
Transition to oral ciprofloxacin
The correct action is to transition the patient to oral ciprofloxacin. This patient with acute pyelonephritis has demonstrated significant clinical improvement after initial intravenous therapy. She is hemodynamically stable, has been afebrile for 24 hours, and is tolerating oral intake. These meet the standard clinical criteria for transitioning from intravenous to oral antibiotics, which reduces hospital length of stay and minimizes the risk of line-associated complications. Fluoroquinolones (such as ciprofloxacin or levofloxacin) and trimethoprim-sulfamethoxazole are the preferred oral agents for pyelonephritis because they achieve excellent bioavailability and high therapeutic concentrations in the renal parenchyma. Since the isolated pathogen is susceptible, oral ciprofloxacin is a highly appropriate choice to complete her treatment course.
Step-by-Step Solution
Key Concept
Patients with acute pyelonephritis who are clinically improving and tolerating oral intake should be transitioned to oral antibiotics with high renal tissue penetration, such as fluoroquinolones (ciprofloxacin) or trimethoprim-sulfamethoxazole. Nitrofurantoin is contraindicated as it does not achieve adequate levels in the kidney.