Exploring the Antimicrobial Efficacy of Mesenchymal Stem Cell Secretome Against Klebsiella pneumoniae in Urinary Tract Infections.

Antimicrobial resistance (AMR) has become a global health crisis, with Klebsiella pneumoniae (K. pneumoniae) emerging as a major driver of AMR and a leading cause of urinary tract infections (UTIs). Mesenchymal stem cell (MSC)-derived secretomes have gained attention for their antimicrobial properties. This study aimed to investigate the antibacterial activity of MSC-derived secretomes against urinary K. pneumoniae isolates. The secretomes derived from adipose tissue (AD-MSCs), bone marrow (BM-MSCs), and umbilical cord (UC-MSCs) were tested against 50 K. pneumoniae clinical strains isolated from urine, including extended-spectrum β-lactamase (ESBL)-, AmpC-, and carbapenem-resistant (CRE) strains. This secretome inhibited 68% of isolates overall, including 81.5% of K. pneumoniae (non-ESBL, non-AmpC, non-CRE), 46.7% of ESBL-, and 100% of AmpC-producing isolates, but showed no effect on CRE isolates. Genotypic analysis revealed that all ESBL-producing isolates (100%) harbored the blaSHV gene and expressed the fimH, wabG, uge, ureA, and entB virulence factors. These findings demonstrate, for the first time, the antibacterial potential of three distinct MSC secretome sources against K. pneumoniae, highlighting their promise as a novel adjunctive therapy for drug-resistant UTIs.