Predict Urinary Tract Infection and to Estimate Causative Bacterial Class in a Philippine Subspecialty Hospital

Objective: Urinary tract infection diagnosis by urine culture can be time- and labor- consuming. In the National Kidney and Transplant Institute, up to 75% of urine culture samples sent to the laboratory yield no growth or insignificant growth. A rapid and reliable screening method to rule out bacterial UTI could reduce culture workload, turnaround time of negative results and also unnecessary antibiotic prescription. Sysmex UF-1000i is urine flow cytometry analyzer which is capable of quantifying urine particles including bacteria and leukocytes. We evaluated the UF-1000i performance for ruling out UTIs and its bacterial scattergram feature to estimate the causative bacterial group, using standard urine culture results as reference method. Methods: 293 urine samples were analyzed using Sysmex UF-1000i analyzer and compared with urine culture results. Bacterial cluster distribution in the bacterial scattergram of positive cultures was also analyzed for causative bacterial class estimation. Results: Out of 293 urine samples, 104 (35.5%) samples had bacterial growth of more than 103 CFU/ml on culture and most common organism isolated was Escherichia coli (28.8%). The optimum bacterial cut off value of 55/μl and/or leukocytes cut-off value of 27/μl were observed using ROC analysis to rule out UTI. The bacterial scattergram analysis showed 82.7% concordance with the results of the urine culture, with only 5.8% discordant results, and 11.5% had results showing non-specific or wide distribution patterns near the 30° angle. Conclusions: Urine samples can be routinely screened for UTI using the Sysmex UF-1000i, and this can improve the overall turnaround time of negative results and reduce laboratory culture workload