PCNL antibiotic regimens compared

Routine administration of an extended preoperative course of antibiotics appears to be an unnecessary strategy for preventing urosepsis after percutaneous nephrolithotomy (PCNL) in high-risk patients with sterile urine, according to urologists from Washington University School of Medicine, St. Louis.

The authors found no significant difference in proportion of patients meeting systemic inflammatory response syndrome (SIRS) criteria post-PCNL comparing groups treated with antibiotics for 7 days preoperatively, 2 days preoperatively, or with a single dose immediately before the procedure (3.7%, 5%, and 4.2%, respectively).

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“Infection after PCNL can be a serious complication, and certain features have been identified that are associated with an increased risk of this event despite the presence of sterile urine prior to the procedure,” said co-author Aaron Potretzke, MD, an endourology fellow at Washington University.

“Although previous studies have suggested that a 7-day course of preoperative antibiotic therapy is beneficial for reducing the risk of SIRS in high-risk patients with sterile urine, our findings indicate there is no reason to extend antibiotic treatment beyond a single perioperative dose,” added Dr. Potretzke, who worked on the study with Brian Benway, MD, and colleagues.

The study, reported at the 2015 AUA annual meeting in New Orleans, looked retrospectively at 292 consecutive patients who had undergone PCNL between January 2012 and June 2014. All patients had urine samples obtained preoperatively, and only 139 patients who had both sterile urine and high-risk features (previous UTI, dilated pelvocaliceal systems, or stone size ≥20 mm) were included in the analysis to determine the rate of SIRS associated with different prophylactic regimens.

There were 27 patients who received a 7-day course of antibiotics, 40 patients treated for 2 days preoperatively, and 72 patients who were given a single perioperative dose. Univariate analysis showed the three groups were similar with respect to gender, mean age, mean stone size, mean duration of surgery, and in their high-risk characteristics.

Next: No significant differences among groups

No significant differences among groups

Multivariable analysis found no statistically significant differences among the groups in proportions of patients with any of the criteria that define SIRS (temperature ≥38°C or <36°C, respiratory rate >20, white blood cell count >12,000 or <4,000 cells/microL, heart rate >100 bpm) or that met all of the SIRS criteria.

Dr. Potretzke explained that the prophylactic regimen used in high-risk patients undergoing PCNL has changed over time. A 7-day course was adopted by several urologists after a paper by Mariappan et al appearing in the November 2006 issue of BJU International reported the week-long regimen reduced the rate of SIRS by about threefold compared with historical controls (BJU Int 2006; 98:1075-9). In 2013, there was a shift to a 2-day course based on a recommendation from infectious disease specialists at Washington University.

“Our infectious disease colleagues were concerned that such prolonged treatment would promote bacterial resistance and noted that it was unnecessary from a pharmacokinetics standpoint since the antibiotic would reach its steady-state level within 48 hours,” Dr. Potretzke told Urology Times.

The relatively large cohort of patients receiving only a single perioperative dose was derived from the practice of a single urologist who was using that regimen all along.

At the 2014 AUA annual meeting, the Washington University urologists presented a study comparing SIRS rates among groups of patients treated with antibiotics for 7 or 2 days preoperatively. The number of patients included in that analysis was smaller, but the results were similar in showing no significant difference between the two regimens.

Dr. Potretzke told Urology Times that the current standard SIRS prophylaxis regimen for high-risk patients undergoing PCNL involves a single preoperative dose of intravenous ampicillin and gentamicin (Garamycin). Ciprofloxacin (Cipro, Proquin) is used as the second-line alternative if there are any contraindications to those antibiotics, except in patients with a history of infection caused by resistant organisms. Then, the antibiotic choice is based on findings from previous culture and sensitivity.

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