Editorial Comments to “Clinical Usefulness of Early Evaluation of the Bacteriological Effect of Antibiotics Administered as Empiric Therapy Using the Fully Automated Urine Particle Analyzer UF‐5000 in Febrile Urinary Tract Infections”

In the treatment of urinary tract infections (UTIs), empirical antibiotic treatment is generally started after obtaining a urine culture. If causative bacteria are resistant to the initial antimicrobial agent, it is necessary to switch to antibiotics based on the antimicrobial susceptibility test (AST). However, AST results take about three days, leading to the overuse of broad-spectrum antibiotics as empiric treatment to avoid treatment failure due to the increasing prevalence of multidrug-resistant uropathogens [1]. Therefore, a method to evaluate the response to initial antibiotics earlier and without using special equipment is warranted. Fully Automated Urine Particle Analyzer UF-5000 is a diagnostic instrument, that can rapidly evaluate clinical parameters and quantify bacteria in urine samples [2, 3]. The recent study conducted by Taguchi et al. published in Int J Urol investigated optimal timing for UF-5000 evaluations after β-lactam antibiotic administration in in vitro experiments and prospectively assessed the potential utility of UF-5000 for rapid evaluation of empiric antibiotic efficacy in febrile UTI patients [4]. They reported that monitoring the bacterial counts on the BACT scattergram of UF-5000 at 6 and 24 h after antibiotic administration was optimal in the in vitro study. In the clinical study, they demonstrated that an increase in bacterial counts from 6 to 24 h was a key predictive factor for early detection of treatment failure or delayed improvement, even when an initial reduction was observed in febrile UTI patients. This study evaluated only β-lactam antibiotics against Gram-negative bacilli, and whether similar findings apply to Gram-positive cocci or other antibiotics, such as quinolones, remains unclear. Furthermore, clinical evaluation was a preliminary design including only 10 cases. Nevertheless, the findings that initial antimicrobial efficacy might be predicted within 24 h using UF-5000, a machine already available in many hospitals worldwide without expensive testing methods, have considerable novelty. Predicting treatment failure within 24 h may allow timely escalation of antibiotics before the patient's condition worsens. Therefore, integration of this monitoring method into antimicrobial stewardship programs could support early decision-making and reduce unnecessary empiric use of broad-spectrum antibiotics because it enables earlier assessment of treatment response without waiting for AST results. As the authors mention, further validation of this monitoring method through multicenter studies involving various types of UTIs could help identify patient populations and causative organisms for which UF-5000-based monitoring is effective. If confirmed, this approach has the potential to change future UTI treatment strategies. The author takes full responsibility for this article. The author declares no conflicts of interest. Taguchi M, Kaido M, Toy N, et al., "Clinical Usefulness of Early Evaluation of the Bacteriological Effect of Antibiotics Administered as Empiric Therapy Using the Fully Automated Urine Particle Analyzer UF-5000 in Febrile Urinary Tract Infections," International Journal of Urology (2025), https://doi.org/10.1111/iju.70190.