Antimicrobial Resistance Patterns in Cases of Obstructive Pyelonephritis Secondary to Stones

ObjectiveTo characterize the local antimicrobial resistance pattern in patients with obstructing ureteral stones and fever, compare this with our local antibiograms, and guide recommendations for empiric antibiotic regimens.MethodsA retrospective chart review was performed of patients who underwent ureteroscopic intervention for the management of ureteral stones at a neighboring private hospital and a public hospital to identify those patients who had undergone prior decompression for obstructing ureteral stones and fever between 2004 and 2011. Urine culture results were captured to identify uropathogens and sensitivity patterns to antibiotics. These were compared with respective hospital antibiograms.ResultsSixty-five patients were identified, of which 35 had positive urine culture results. More than 25% of the voided urine and upper urinary tract urine cultures differed. Antimicrobial resistance patterns were higher for patients at the public hospital than the hospital antibiogram. The opposite was true at the private hospital. The public hospital demonstrated an overall higher resistance pattern than the private hospital.ConclusionAntimicrobial resistance makes the selection of empiric antibiotic treatment challenging in patients with obstructive pyelonephritis secondary to ureteral stones. Because of discordance between voided urine cultures and those captured at the time of decompression, it is imperative to obtain both voided urine and urine from the kidney to ensure adequate antibiotic coverage. Local population-specific antimicrobial guidelines that are frequently updated are essential to ensure adequate coverage and treatment of obstructive pyelonephritis, and condition-specific antibiograms would be recommended in the future.