< 0.0001), converting several previously negative or low-count samples into positive cultures. Agreement between viable and culturable fractions improved after DTT treatment, primarily through reduced systematic bias in Bland-Altman analysis, while correlation coefficients remained similar (r: 0.44 vs 0.45). A persistent discrepancy between FACS-derived viable counts and culture-based counts suggests the presence of viable bacterial populations not fully recovered by standard culture conditions, findings that are consistent with but do not directly demonstrate the presence of VBNC subpopulations. Low-dose DTT is a safe and effective pre-analytical treatment that markedly improves culture sensitivity without compromising bacterial viability. These findings support further investigation of DTT-assisted processing as a potential strategy to reduce culture underestimation in urinary diagnostics and to better characterize viable bacterial populations not detected by standard culture methods.IMPORTANCEStandard urine culture may fail to detect the full spectrum of bacteria present in urinary tract infections, particularly when microorganisms are embedded within mucus, biofilm-like aggregates, or enter a viable but non-culturable state. These hidden bacterial populations may contribute to persistent symptoms or recurrent infections while remaining undetected by routine culture methods. Our findings suggest that pre-treating urine samples with a low concentration of dithiothreitol may help disperse biofilm-like aggregates while preserving bacterial viability. When combined with flow cytometry, this approach may allow a more comprehensive estimation of the viable bacterial fraction and, in some cases, may increase the likelihood of bacterial recovery by culture in samples that would otherwise appear negative. Because the procedure relies on inexpensive reagents and techniques compatible with routine laboratory workflows, it may represent a practical adjunct to conventional diagnostics. Further studies are needed to confirm its clinical impact.
Motte et al. (Tue,) studied this question.