Comparative study of antibiotic resistance and virulence profiles of exoU and exoS Pseudomonas aeruginosa isolates from urinary tract infections and microbial keratitis in Bangladesh and India.

Pseudomonas aeruginosa is an important opportunistic pathogen in urinary tract infections (UTIs) and microbial keratitis (MK), but differences in resistance and virulence between exoU and exoS P. aeruginosa isolates across regions and infection sites remain poorly understood. This study compared antibiotic resistance and virulence profiles of exoU and exoS P. aeruginosa isolates from Bangladeshi and Indian UTIs, and from Indian UTIs and MK collections. A total of 23 Bangladeshi UTI isolates were analyzed by broth microdilution for susceptibility to ciprofloxacin, levofloxacin, gentamicin, and tobramycin, and by whole-genome sequencing (WGS) to identify resistance-associated mutations, acquired resistance genes, and virulence factors. These WGS data were compared with 15 publicly available Indian UTI genomes, while the Indian UTI genomes were compared with 19 publicly available Indian MK genomes. In the Bangladeshi UTI cohort, exoU isolates showed greater resistance to fluoroquinolones and aminoglycosides than exoS isolates. Comparative analysis of Bangladeshi versus Indian UTI isolates and Indian UTI versus MK isolates showed that exoU isolates carried a burden of resistance mutations, including enrichment of GyrA Thr83Ile, ParE Asp533Glu, MexR Val126Glu, MexB Ser1041Glu, and MexC Ala262Glu. Aminoglycoside-associated substitutions FusA2 Gln161Leu and ParR Leu153Arg and Ser170Asn were more common in exoU UTI isolates. Acquired resistance genes showed aac(6')-II and aac(3)-Id were linked to Bangladeshi UTI, rmtF associated with Indian UTI, and crpP confined to MK exoU isolates. Virulence profiling showed exoU enrichment in pldA, pvdY, and csrA, whereas exoS was associated with pilC, pilV, pilW, pilY2, and pilA. Collectively, these results indicate that exoU and exoS isolates differ in both their resistance and virulence profiles, while also showing evidence of geographic and infection-site-specific adaptation.