Resistome profiling and bacterial community structure of semi-urban gutter ecosystems of India

Environmental factors contribute to antimicrobial resistance, a global health threat. Contaminated gutter water in urban areas spreads resistant bacteria, disrupting ecosystems and promoting biofilm formation, causing widespread concern. This study aimed to evaluate antibiotic-resistant bacterial populations across six gutter ecosystems in Roorkee, Uttarakhand, India during summer against different classes of antibiotics, identify presence of beta-lactamase, and explores total bacterial communities, and predicting metabolic pathways through 16S rRNA based metagenomic approach of V3 region. The highest resistant bacterial population was found in HL_NS-6, and HL_NS-2, with highly resistance to Penicillin (ampicillin and oxacillin), Cephalosporin (Cephalothin), aminoglycoside (Kanamycin), fluoroquinolone (ciprofloxacin), and Antifolate (Trimethoprim) class antibiotics. Beta-lactamase activity was detected in all samples except HL_NS-5, indicated by nitrocefin hydrolysis. The microbial community in the six samples were composed with the major families enterobacteriaceae (15.4%) and pseudomonadaceae (8.29%), covering 23.7% of the total population. The highest taxa were found in HL_NS-2 and HL_NS-4, while the largest genera were Pseudomonas (8.3%), Escherichia (8.2%), Hydrogenophaga (6.85%), and Candidatus Moranella (5.4%). There were 21.25% common bacterial genera were present as core microbiome and rest were signified the population diversity among the six-gutter microbiome. The coexistence of common metabolic pathways (citric acid cycle, carbon, nitrogen metabolism etc.), and streptomycin, glycosphingolipid, lipopolysaccharide, cyanoamino acid metabolism pathways might be induced the development of antibiotic resistance in gutter microbiome. This study suggests the presence of antibiotic-resistant bacteria with antibiotic resistant metabolic pathways, and beta-lactamase genes in urban gutter water, which could be harmful to both human health and environmental ecosystems.