Microbiological Features and Clinical Factors Associated with Empirical Antibiotic Resistance in Febrile Patients with Upper Urinary Tract Calculi

Background To investigate the clinical and microbiological features of febrile patients with upper urinary tract calculi and factors that affect empirical antibiotic resistance. Methods A retrospective analysis was performed on 203 febrile patients hospitalized between January 2011 and December 2016 with antibiotic treatment for urinary tract infections and upper urinary tract calculi at three institutions. We collected and analyzed data, including patients' age, sex, body mass index, underlying diseases, stone-related factors, and the results of urine and blood culture examinations and antibiotic sensitivity tests. Results The male-to-female ratio was 1:2.3. Bacteria were identified in 152 of the 203 patients (74.9%). The most commonly cultured microorganisms included Escherichia coli (44.1%), followed by Enterococci spp. (11.8%), Proteus spp. (8.6%), Streptococcus agalactiae (6.6%), Klebsiella spp. (5.3%), Pseudomonas spp. (4.6%), coagulase-negative Staphylococcus (4.0%), Staphylococcus epidermidis (4.0%), Serratia spp. (2.6%), Enterobacter spp. (0.7%), Acinetobacter spp. (0.7%), and mixed infections (7.2%). Cultured bacterial species showed sex-specific differences. Multivariate analysis revealed that calculi's multiplicity was an independent predictive factor for quinolone resistance (P = 0.008). Recurrent infections were a significant predictor of cefotaxime resistance during multivariable analysis (P = 0.041). Conclusion Based on the present study results, quinolone was not recommended as the empirical treatment in febrile patients with upper urinary tract calculi. Combination antibiotic therapy is recommended in cases of recurrent infections due to the possible occurrence of cefotaxime resistance.