In Vitro Characterization Of Antimicrobial Resistance And Biochemical Signatures Of Pathogens From Environmental Reservoirs In Pakbara, Moradabad, Uttar Pradesh, India.

Background: This study aimed to characterize the AMR profiles and biochemical markers of pathogens from environmental sources to guide public health strategies. Materials and Methods: From March 10 to April 10, 2025, a total of 340 environmental samples were collected from high-, moderate-, and low-risk areas in Pakbara, including soil (n=136), water (n=102), and surface swabs (n=102). Samples were cultured on selective media such as MacConkey and cetrimide agar. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion method for amoxicillin, ciprofloxacin, vancomycin, and ceftriaxone, adhering to CLSI guidelines. Biochemical assays included nitrocefin tests for beta-lactamase and chrome azurol S (CAS) assays for siderophore production. Statistical analysis employed chi-square, ANOVA, and logistic regression, with significance set at p<0.05. Results: Pathogenic organisms were detected in 30.6% (104/340) of samples, with water samples showing the highest prevalence (35.3%) and bacterial load (mean: 4.85 log CFU/mL). Escherichia coli (40.4%) and Staphylococcus aureus (29.8%) were the most frequently identified species. AMR prevalence ranged from 25.0% (vancomycin) to 32.7% (amoxicillin), and 17.3% of isolates were classified as multidrug-resistant. Beta-lactamase activity was present in 36.5% of isolates, and siderophore levels were notably elevated in water-derived samples. Both sample type (χ² = 12.45, p = 0.014) and environmental risk level (χ² = 8.76, p = 0.013) were significantly associated with AMR, while beta-lactamase production was a strong predictor of multidrug resistance (OR = 3.45, p = 0.002). Conclusion: The study underscores the role of environmental water reservoirs in Pakbara as significant contributors to the spread of AMR pathogens. The high prevalence of beta-lactamase-producing and multidrug-resistant strains calls for immediate implementation of sanitation improvements and robust diagnostic surveillance in semi-urban regions to mitigate the public health risks posed by environmental AMR.