Search

Abstract: Because urinary tract infections (UTIs) are a quite common disease, the gold standard for diagnosing UTIs is still bacterial culture, although a large percentage of samples are negative: unnecessary cultures can be reduced by means of an effective screening test. The analytic performance of a new urine cytometer, the UF-1000i, has been tested on 1463 urine samples submitted to our laboratory for culture. Bacteria and leukocyte counts have been compared by means of the UF-1000i with colony-forming unit (CFU) quantification on citrate lactose electrolytes deficient agar to assess the best cutoff values. By using quantitative cultures and considering as positive a sample with 10 × 105 CFU/mL, 546 positive samples (37%) were observed. If compared with 10 × 105 CFU/mL, the cutoff values obtained were 125 bacteria/μL and 40 leukocytes/ μL, respectively. Analytic parameters such as sensitivity, specificity, positive predictive value, negative predictive value, and correctly classified incidence were satisfactory. Based on the results obtained in this study, when using the UF-1000i analyzer for a screening test for UTI, a cutoff value of 40 white blood cells/μL should be adopted. The cutoff value for bacteria should be 125/μL for those clinical conditions in which 10 × 105 CFU/mL indicates a positivity. [Copyright &y& Elsevier]

Abstract: Background: Urinary tract infections (UTIs) are usually diagnosed by urine particle detection and urine bacterial culturing, but an empiric treatment is often prescribed before the microbiological results are known. The aim of this study was to assess whether quantification of bacteriuria and leukocyturia could predict the outcome of empiric antibiotic therapy. Methods: By using a Sysmex UF-100 analyser, we performed a case–control study in which bact channel counts (BCCs) and leukocyte (WBC) quantification were compared in urine samples obtained from responsive patients (RPs) and non-responsive patients (NRPs) at diagnosis (t0) and 24h (t24) after the start of empiric antibacterial treatment. Results: BCCs decreased significantly from t0 (median: 30,000 E6/L) to t24 (median: 700 E6/L; p <0.001) in RPs but not in NRPs (median at t0 31,000 E6/L, and 23,000 E6/L at t24; p >0.05). Similarly, WBC counts were reduced in RPs at t24 relative to the initial values (p <0.001) but not in NRPs. A reduction of 70% in the BCC count or 60% in the WBC count of paired samples was useful for discriminating between RPs and NRPs. Conclusions: Our results suggest that quantitative time course analysis of urine BCCs and WBCs can be used to predict the success of first-line empiric treatment for UTIs. [Copyright &y& Elsevier]