Report of Antibiotic Resistance in Urban and Rural Wastewaters from West Bengal, India

Aims: This study aims at comparative identification of antibiotic resistance patterns in bacteria isolated from samples collected from rural environment (LS) and urban environments (SS). Metagenomic profiling gave us insights into the microbial abundance of the two samples. This study focused on culture-based methods for complete identification of antibiotic resistant isolates and estimation of comparative antibiotic resistance among the two samples.

Study Design: Untreated medical waste and anthropogenic waste disposal can lead to the propagation of different antibiotic resistant strains in wastewater environments both in urban and rural set ups which provide an insight towards this study approach mentioned in the methodology segment.

Place and Duration of Study: Sewer system of a medical facility located in Purulia, India was the collection site for liquid sludge. Solid sludge and associated wastewater were collected in vicinity of a large urban medical facility from central Kolkata, India.

Methodology: Physico-chemical properties were analyzed followed by microbiological and biochemical characterization. The antibiotic resistance patterns were determined by Kirby-Bauer disc diffusion assay. Potent multidrug resistant isolates were identified using 16srRNA gene amplification followed by Phylogenetic profiling, using CLC Genomics workbench.

Results: We observed maximum resistance in an E. coli isolate which was resistant up to 22 antibiotics. Combined data for resistance from urban and rural samples were found to exhibit 83.9% resistance to beta lactams, 85.7% to macrolides, 44.2% to fluoroquinolones, 50% to glycopeptides and cephalosporins, 35.7 % to carbapenems and sulfonamides, 28.5 % to tetracycline, and 23.8 % to aminoglycosides.

Conclusion: The high prevalence of antibiotic-resistant bacteria harbouring diverse resistance traits across samples indicated towards probable horizontal gene transfer across environmental niches. This study can prove to be useful to understand and map the patterns of resistance and stringently apply the counter measures related to public health practices.