Etiology and bacterial susceptibility to antibiotics in patients with recurrent lower urinary tract infections.

INTRODUCTION Recurrent urinary tract infections (rUTI) are a frequent health problem and a common reason for treatment resistance. OBJECTIVES The purpose of the study was to evaluate the etiology of community-acquired lower rUTI and bacterial antibiotic susceptibility. PATIENTS AND METHODS 796 microbiological urine cultures (UC) from 332 patients (280F, 52M) treated in one nephrology outpatient department in central Poland in years 2016-2018 were analyzed. The most frequent species responsible for lower rUTI were identified and the susceptibility of all the microbes to specific antibiotics was assessed. The patients' kidney function and inflammation parameters were evaluated. RESULTS The age of the patients was 65.0 (59.0-77.0) [F: 69.0 (57.0-78.0), M: 67.0 (62.0-77.0)], glomerular filtration rate was 56.6 (40.2-81.3) ml/min/1.73 m2 with C-reactive protein: 3.2 (1.5-7.0) mg/l. 43 bacterial species were identified: 24 Gram-positive, 19 Gram-negative. The analyzed UCs contained 977 microbial samples (563 Gram-negative bacteria, 408 Gram-positive, 6 fungi). The most common bacteria was Escherichia coli 39.6% that showed 100.0% susceptibility to carbapenems, 98.9% to amikacin, 96.5% to piperacilin/tazobactam and 94.3% to gentamicin, among the oral antibiotics its highest susceptibility was to: fosfomycin 95.5%,  nitrofurantoin 85.5% and cefuroxime 82.3%. In 39.9% of cases E. coli was resistant to fluoroquinolones and in 46.6% to trimethoprim/sulfamethoxazole. CONCLUSIONS The most frequently occurring bacteria causing lower rUTI are characterized by significant resistance to the antimicrobial therapy recommended as the first-line treatment: fluoroquinolones and trimethoprim/sulfamethoxazole. It seems that the first choice in treatment of lower UTIs should be: fosfomycin, nitrofurantoin or cefuroxime.