Antimicrobial Resistance Patterns of Uropathogens Causing Urinary Tract Infections in Different Age Groups and Clinical Populations

Urinary tract infections (UTIs) are among the most prevalent bacterial infections globally, and their clinical management is increasingly complicated by the emergence of antimicrobial resistance in causative uropathogens. Resistance patterns are known to vary with patient age and clinical condition; however, comparative data stratified across distinct patient populations remain limited. This study aimed to isolate and identify uropathogens from three clinically defined patient groups: individuals below 25 years of age, individuals above 25 years, and hospitalized stroke patients. We also compared their antimicrobial resistance profiles to characterize the influence of age and clinical setting on resistance. A cross-sectional observational study was conducted at the Ayurgreen Scientifica Research Institute from October 2025 to March 2026. A total of eighteen midstream urine samples were collected from symptomatic patients at Ayurgreen Hospitals, Kerala, India, and Getwell Hospitals, Naduvattam, Kerala, India. Samples were cultured on Blood Agar and MacConkey Agar, and bacterial isolates were identified using Gram staining. Further biochemical characterization of the isolates was performed using the IMViC battery and the catalase, oxidase, coagulase, and motility tests. Antimicrobial susceptibility testing was performed using the Kirby–Bauer disc diffusion method on Mueller–Hinton Agar against 18 antibiotics, and the results were interpreted according to the Clinical and Laboratory Standards Institute (CLSI M100, 2023) guidelines. Pseudomonas spp. were the most frequently isolated organisms (44.4%), followed by Escherichia coli (22.2%) and Klebsiella spp. (16.7%). Isolates from patients below 25 years of age generally demonstrated higher susceptibility to the tested antibiotics, whereas isolates from patients above 25 years exhibited moderate susceptibility. The stroke patient group showed the highest frequency of multidrug-resistant isolates, including resistance to carbapenems and fluoroquinolones, among several Pseudomonas isolates. Earlier-generation β-lactams and fluoroquinolones demonstrated reduced activity across the study groups, whereas aminoglycosides and nitrofurantoin retained comparatively better antimicrobial activity. The findings indicate differences in antimicrobial susceptibility patterns among uropathogens isolated from the three groups, with multidrug-resistant organisms being more frequently observed in the hospitalized stroke cohort. These results support the importance of continuous local antimicrobial resistance surveillance and patient-specific empirical treatment strategies to promote appropriate antimicrobial use and strengthen antibiotic stewardship.