2118 ANTIMICROBIAL RESISTANCE PATTERNS IN PATIENTS WITH FEBRILE STONES

Abstract

INTRODUCTION AND OBJECTIVES: Obstructing ureteral stones with fever are a urological emergency. These patients are treated with emergent decompression in addition to receiving empiric antibiotic therapy secondary to risk of urosepsis. Antimicrobial resistance is a growing concern and the choice of antibiotic therapy is critical in the prevention of urosepsis and its sequelae. METHODS: Retrospective chart review was performed of all patients who underwent ureteroscopic intervention for the management of ureteral stones to identify those patients who had prior decompression for febrile stone presentations from 2004 to 2011. Febrile stone was defined as any patient who had an obstructing ureteral stone and fever / 100.3. RESULTS: 65 patients were identified of which 35 had positive urine cultures; 5 patients were infected with 2 uropathogens. 38 uropathogens were bacterial and 2 were fungal. 30 of 38 (79%) of the bacteria were gram negative rods (GNRs) and E. coli (66%) was the most common GNR. The most common gram positive cocci (GPC) was Enterococcus (63%). Antimicrobial resistance patterns for GNRs and GPC are presented in Table 1. There was a high level of resistance to several antibiotics commonly used to cover GNRs when treating UTIs, including fluoroquinolones, trimethoprim-sulfamethoxazole, nitrofurantoin, gentamicin, ampicillin, and ampicillin-sulbactam with resistance rates of 30%, 30%, 31%, 17%, 59%, and 30% respectively. Third and fourth generation cephalosporins, carbapenems, amikacin, and piperacillin-tazobactam still maintained good activity against GNRs. GPCs have high resistance patterns to commonly used parenteral antibiotics. CONCLUSIONS: Antimicrobial resistance can make the selection of empiric antibiotic treatment challenging in patients with febrile stones. Given the high resistance rates, we recommend using a third or fourth generation cephalosporin, piperacillin-tazobactam or amikacin as empiric antibiotic therapy for patients with febrile stones to cover for GNRs until culture-specific antibiotics are determined. Carbapenems are also highly active but much more expensive and are not recommended as first line treatment except in cases where prior resistance patterns are known. These results may only be applicable to our region; however, this stresses the importance of determining local susceptibility profiles. Table 1: Antimicrobial resistance patterns GNRs