Correlation appraisal of antibiotic resistance with fecal, metal and microplastic contamination in a tropical Indian river, lakes and sewage

摘要

The present study compares the prevalence of antibiotic-resistant bacteria (ARB) in the urban water of Ahmedabad (India), to understand the correlation of ARB with the fecal, metal, and microplastic contamination. Eleven samples, i.e., three locations of Sabarmati River along with one sample each from two (Chandola and Kankaria) lakes, and influents and effluents from three Sewage Treatment Plants (STPs) were analyzed in this study. E. coli isolated from the samples were subjected to three fluoroquinolones (Levofloxacin (LVX), Ciprofloxacin (CIP), and Norfloxacin (NFX)) and three non-fluoroquinolones (Kanamycin Monosulphate (KM), Tetracycline (TC), and Sulfamethoxazole (ST)) antibiotics for resistance quantification. Prevalence of the E. coli in the Sabarmati River (19,467–76,600 cfu mL1) was higher than the lakes and STP(s), except the influent sample at Juhapura STP. Among the lake samples, Kankaria Lake (KL) exhibited 0% resistance towards all six antibiotics despite 5× prevalence of E. coli than that of Chandola Lake (CL) exhibiting up to 60% resistance for non-fluoroquinolones and 40% resistance to NFX. Multivariate statistical analyses suggest that resistance for ST, KM, and TC is more prevalent and correlated with electrical conductivity (EC), finer size microplastic, manganese (Mn), and nickel (Ni), whereas the resistance for fluoroquinolones (LVX, CIP, and NFX) seems highly influenced by seasonal temperature variation. Larger size microplastic clustered with salinity, ORP, and Pb. Further, fecal contamination and antibiotic resistance seem to be governed by the same source and processes, yet it does not show good correlation except for the river samples. This result may be attributed to the dynamic river–human interface, substantial wastewater discharge into the river, stagnant water flow, and urbanization-related discharge conditions rather than the upstream condition.