Urinary Secretory‐ IgA and IgG Responses and Inflammatory Markers in Patients With Pseudomonas ae

ABSTRACT

Recurrent UTIs (rUTIs) impair quality of life and contribute to antimicrobial resistance. Pseudomonas aeruginosa is particularly challenging due to intrinsic and acquired resistance. Identification of urinary biomarkers may improve understanding and diagnosis of localized and systemic UTIs. Urine anti‐ P. aeruginosa secretory IgA (s‐IgA), IgG, and a selection of inflammatory markers were quantified using ELISA and Luminex. Urine samples with P. aeruginosa ‐positive cultures ( n  = 28), healthy controls ( n  = 23), culture‐negative hospitalized patients ( n  = 25), and cultures positive for Escherichia coli or Enterococcus faecalis ( n  = 27) were included. Anti‐ P. aeruginosa s‐IgA and IgG were highest in P. aeruginosa cases (median OD s‐IgA 0.2040; IgG 0.4330) and exceeded healthy controls (s‐IgA p  < 0.001; IgG p  < 0.0001). No difference was observed between single and rUTI, but s‐IgA in multiple P. aeruginosa ‐positive rUTIs was increased versus healthy ( p  = 0.0034) and culture‐negative controls ( p  = 0.0228). IL‐8 (297.5 vs. 27.00 pg/mL, p  = 0.002), lipocalin (32,440 vs. 6673 pg/mL, p  = 0.0287), and IL‐6 (11.0 vs. 6.5 pg/mL, p  = 0.011) were elevated compared to healthy controls. Urinary s‐IgA best reflected P. aeruginosa UTI status, while IL‐8, lipocalin, and IL‐6 may indicate UTI.