Comparison of antimicrobial resistance in Gram negative bacteria isolated from effluents in coastal districts of Karnataka, India

Abstract

AbstractDownstream water systems provide for a conducive environment for horizontal gene transfer. The objective of this study was to determine the burden of antimicrobial resistance in waste water effluents from different sources and their impact on human health. Gram negative bacteria were isolated from 30 samples each of industrial, hospital and domestic effluents. The antimicrobial susceptibility of the 367 isolates from 90 effluent samples was determined by disc diffusion test and presence of antimicrobial resistance genes by polymerase chain reaction. Resistance to ampicillin was 62% in hospital effluents and was higher than that recorded for industrial and domestic effluents. While the highest percentage of resistance to tetracycline was observed in isolates from industrial effluents (42%) a low of 9.5% was observed in hospital effluents. Antimicrobial resistance determinants present on mobile genetic elements were observed in a small fraction (~10%) of the resistant isolates. The resistance profile of isolates in effluents reflect the practices of different industries. Resistant isolates in domestic effluents could be a reflection of the indiscriminate use of antibiotics andthat many of the contents of disinfectants and cleaning agents routinely used may contain structural analogs of antimicrobials used in therapy. Though by phenotypic test a higher prevalence of antimicrobial resistance was recorded the genotypic study revealed the prevalence to be low. This could be due to the limited number of antimicrobial resistance genes included in this study.