Screening Biomarkers and Constructing a Predictive Model for Symptomatic Urinary Tract Infection and Asymptomatic Bacteriuria in Patients Undergoing Cutaneous Ureterostomy: A Metagenomic Next-Generation Sequencing Study

Abstract

Objectives. To investigate the clinical diagnostic value of differential flora as biomarkers in patients with symptomatic urinary tract infection (UTI) and asymptomatic bacteriuria (ASB) undergoing cutaneous ureterostomy based on metagenomic next-generation sequencing and construct predictive models to provide a scientific reference for clinical diagnosis and treatment. Material and Methods. According to standard procedures, samples were taken from each patient for routine tests (urine, ureteral stent, and skin swab around the stoma). Cytokine levels in the blood were also detected. Urinary microflora were measured by mNGS, and potential biomarkers for distinguishing UTI and ASB were identified by differential flora. Finally, we generated the predictive models for ASB and UTI using the Lasso method and cytokine levels. Results. Urine culture was performed for 50 patients with cutaneous ureterostomy; 44 of these patients developed bacteriuria. The incidence of symptomatic bacteriuria was 54.55%. Biomarker analysis showed that Propionimicrobium lymphophilum, Staphylococcus haemolyticus, Stenotrophomonas maltophilia, Ralstonia insidiosa, and Aspergillus sydowii all had good predictive performance and were combined in a single model. The predictive model exhibited good prediction performance (area under the curve AUC = 0.8729 , sensitivity = 80 % , specificity = 83.3 % , and cutoff = 1.855 ). We also identified a significant negative correlation between the weight sum of the abundance for these five characteristic pathogens (Sum_weighted_Reads) and levels of the cytokine IL-6 and IL-1β ( P < 0.05 ). Conclusion. mNGS had a higher positive detection rate for pathogens in urine samples. The selected differential bacteria can be used as biomarkers of ASB and UTI, and the prediction model has good predictive performance. Analysis also showed that the occurrence of symptoms was related to individual immunity. Combined with the Sum_weighted_Reads cutoff and cytokine levels (IL-6 and IL-1β) of differential flora, it was possible to judge the severity of symptoms in cutaneous ureterostomy patients with bacteriuria and provide new insights for the treatment and intervention of ASB and UTI.

Elevated UTI Biomarkers in Symptomatic Patients with Urine Microbial Densities of 10,000 CFU/mL Indicate a Lower Threshold for Diagnosing UTIs

“…Each subgroup median value was compared to the “no microbes detected” group median using the Wilcoxon test. Previously published thresholds for biomarker positivity were used as cutoffs for the analysis: NGAL ≥ 38 ng/mL, IL-8 ≥ 20.6 pg/mL, and IL-1β ≥ 12.4 pg/mL [ 34 , 35 ]. This study defined biomarker consensus as any two or all three of the biomarkers positive at or above the cutoff levels.…”

Urinary tract infection in the context of mini-invasive procedures after kidney transplantation

“…In many studies, a fi nding of ≥ 10 5 CFU/ml of urine was defi nied as a positive urine fi nding (3,9,10). According to the guidelines published by the Infectious Diseases Society of America (IDSA) asymptomatic bacteriuria is defi ned as the presence of at least one type of bacterial growth in urine with a bacterial count ≥ 10 5 CFU/ml irrespective of whether pyuria is present or not and if there are no symptoms or signs attributable to UTI (11). A study by Lee et al considered the presence of ≥ 10 4 CFU/ml as a positive urine fi nding, which agrees with the criteria of our analysis (5).…”

Comparison Shows that Multiplex Polymerase Chain Reaction Identifies Infection-associated Urinary Biomarker–positive Urinary Tract Infections That Are Missed by Standard Urine Culture

“…The biomarker analysis was performed using ELISA kits purchased from R&D Systems/Bio-Techne (Minneapolis, MN, USA), including human Lipocalin-2/NGAL Quantikine ELISA Kit (Catalog number SLCN20), human IL-8/CXCL8 Quantikine ELISA Kit (Catalog number S8000C), and human IL-1β/IL-1F2 Quantikine ELISA kit (Catalog number SLB50), as per the manufacturer’s instructions. Biomarker “positivity” was determined using thresholds presented previously in the literature (NGAL ≥38.0 ng/ml, IL-8 ≥20.6 pg/ml, and IL-1β ≥12.4 pg/ml) [18] , [19] . For this analysis, “consensus” was defined as two or more biomarkers meeting the positivity threshold.…”