What antibiotics are recommended for an infected obstructed kidney stone (nephrolithiasis)?

From the Guidelines

For an infected obstructed kidney stone, empiric broad-spectrum antibiotics should be started immediately after obtaining blood and urine cultures, with a recommended first-line regimen of a combination of an anti-pseudomonal beta-lactam such as piperacillin-tazobactam (3.375-4.5g IV every 6 hours) or cefepime (2g IV every 8-12 hours), plus an aminoglycoside like gentamicin (5-7mg/kg IV once daily) 1. The choice of antibiotics is crucial in managing infected obstructed kidney stones, as the infection often involves gram-negative organisms including Escherichia coli, Klebsiella, Proteus, and Pseudomonas.

• The recommended antibiotics are necessary to cover a broad spectrum of potential pathogens.
• Therapy should be adjusted based on culture results and continued for at least 7-14 days.
• Alternative options include carbapenems such as meropenem (1g IV every 8 hours) or imipenem-cilastatin (500mg IV every 6 hours) 1. However, antibiotics alone are insufficient, and urgent decompression of the collecting system via percutaneous nephrostomy or ureteral stenting is essential within 12-24 hours to relieve the obstruction 1.
• Without drainage, antibiotics cannot effectively reach the infection site due to the obstruction, and the patient remains at high risk for urosepsis, which can be life-threatening.
• After the acute infection resolves, definitive stone management can be addressed. Key considerations in managing infected obstructed kidney stones include:
• Prompt initiation of empiric broad-spectrum antibiotics
• Urgent decompression of the collecting system
• Adjustment of therapy based on culture results
• Continuation of antibiotics for at least 7-14 days
• Definitive stone management after resolution of the acute infection.

From the FDA Drug Label

When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

The recommended antibiotics for an infected obstructed kidney stone (nephrolithiasis) are not explicitly stated in the provided drug labels. However, piperacillin-tazobactam is mentioned as a treatment option for various infections, including those caused by bacteria that may be involved in nephrolithiasis.

• The usual total daily dosage of piperacillin-tazobactam for adult patients with indications other than nosocomial pneumonia is 3.375 grams every six hours [totaling 13.5 grams (12.0 grams piperacillin and 1.5 grams tazobactam)] 2.
• The recommended duration of piperacillin-tazobactam treatment is from 7 to 10 days 2. It is essential to note that the treatment of infected obstructed kidney stones should be guided by culture and susceptibility results, as well as local epidemiology and susceptibility patterns. 2 3 3

From the Research

Antibiotic Recommendations for Infected Obstructed Kidney Stones

• The mainstay of treatment for infected kidney stones is complete stone removal, and antibiotic therapy is recommended for infected obstructive stones 4.
• Current guidelines recommend antibiotic therapy for infected obstructive stones and stone removal in a timely fashion, but there is no clear recommendation for prophylactic antibiotic use for bacteriuria or pyuria in the setting of obstructive ureteral stones 5.
• Fluoroquinolones have shown excellent results in prophylaxis and therapy for post-operative infection control after percutaneous and ureteroscopic removal of stones 6.
• A prospective randomized trial found that 2-weeks or 12-weeks of postoperative antibiotics after percutaneous nephrolithotomy in complex patients with infection-related kidney stones did not result in significantly better outcomes for stone recurrence and positive urine cultures 7.
• A systematic review of the literature suggests that routine antibiotic prophylaxis might not be necessary for all patients with sterile urine undergoing ureterorenoscopy and lithotripsy, but it is beneficial for patients with positive preoperative urine cultures, reducing the risk of postoperative infective complications 8.

Specific Antibiotics Mentioned

• Nitrofurantoin or culture-specific antibiotic were used in a prospective randomized trial for postoperative oral antibiotics after percutaneous nephrolithotomy 7.
• Fluoroquinolones are recommended for prophylaxis and therapy for post-operative infection control after percutaneous and ureteroscopic removal of stones 6.