Anthropogenic impact and antibiotic resistance among the indicator and pathogenic bacteria from several industrial and sewage discharge points along the coast from Pydibhimavaram to Tuni, East Coast of India

Increasing urbanization and industrialization of the Visakhapatnam region have brought domestic sewage and industrial wastewater discharge into the coastal ocean. This study tries to look at the quantitative abundance of the indicator and pathogenic bacteria and their antibiotic susceptibility. As part of this study, both surface and subsurface water samples were collected from ten different regions (147 stations; 294 samples) which included 12 industrial discharge points, surrounding stations and two harbours from the coast of Pydibheemavaram to Tuni. Physicochemical parameters like salinity, temperature, fluorescence, pH, total suspended matter, nutrients, chlorophyll- a , and dissolved oxygen of the water showed a difference from one region to other. We noticed the presence of indicator ( Escherichia coli and Enterococcus faecalis ) and pathogenic ( Aeromonas hydrophila , Klebsiella pneumoniae, Proteus mirabilis , Pseudomonas aeruginosa , Salmonella and Shigella , Vibrio cholera and Vibrio parahaemolyticus ) bacteria among the samples. Waters from the near harbour and Visakhapatnam steel plant showed lower bacterial load where there is no direct input from industries to the coastal water. Samples collected during the industrial discharge period had a higher bacterial load including E. coli . Enteric bacteria were found in higher numbers at most of the stations with some isolates being resistant to multiple antibiotics with higher antibiotic resistance (AR) and multiple antibiotic resistance (MAR) indexes compared with the other coastal water habitats in the Bay of Bengal. The occurrence of these bacteria above the standard limits and with multiple antibiotic resistance in the study region may pose a potential threat to the local inhabitants and can create an alarming situation in the coastal waters in the study region.