Screening Bacteriuria Using the Sysmex UF-5000 during Intravesical Bacillus Calmette-Guérin Therapy for Bladder Cancer.

Abstract

Intravesical Bacillus Calmette-Guérin (BCG) therapy for bladder cancer requires screening for urinary tract infection during treatment, but conventional urinalysis cannot reliably distinguish bacteriuria from BCG-induced inflammatory cystitis. This study evaluated the ability of the Sysmex UF-5000 urine flow cytometer to detect significant bacteriuria and predict Gram stainability during intravesical BCG. This retrospective study included 145 patients who underwent intravesical BCG therapy after transurethral resection of bladder tumors (TURBT). Urine flow cytometry and cultures were performed at baseline, after TURBT, and weekly during BCG instillation. Diagnostic performance was assessed at the patient level over the BCG induction course, using urine cultures (≥10⁵ CFU/mL) as the reference standard. Among 145 patients (median age 71 years; 88.3% male), 37 (25.5%) developed significant bacteriuria. A UF-5000 cutoff of >100 bacteria/µL identified bacteriuria with a sensitivity of 94.6% (95% CI, 82.3-98.5) and specificity of 68.5% (95% CI, 59.3-76.5), and a binary-classifier AUC of 0.816 (95% CI, 0.727-0.905); >1,000 bacteria/µL yielded 62.2% sensitivity, 96.3% specificity, and AUC 0.792. For Gram-stain prediction, sensitivity/specificity reached 83.3%/92.2% (Gram-negative) and 81.0%/84.2% (Gram-positive). The Sysmex UF-5000 shows promise as a rapid screening tool for bacteriuria and Gram-stain prediction during intravesical BCG therapy. Larger prospective studies are needed to validate optimal cutoff values for routine clinical application.