Antibiotics have been extensively and effectively used in human and veterinary medicines. Their benefits have been recognized in agriculture, aquaculture, bee‐keeping, and livestock as growth promoters. This paper collects information from several investigations on the sources and occurrences of antibiotics in natural and artificial environmental systems. Several antibiotics were reported for their occurrences in water resources, effluent from industries, sludge, manure, soil, plants, and organisms across the globe. Sorption, photo‐degradation, biodegradation, and oxidation were recognized as the main elimination pathways for these compounds and have been discussed in detail. The adverse effects of the pollutants were also highlighted and necessary suggestions were made for effective monitoring and mitigating pollution, which may provide the scope for future research.

In the present investigation, feasibility of dairy waste water (DWW) and distillery spent wash (DSW) effluents in increasing the growth and yield of two species of oyster mushroom, Pleurotus flabellatus (PF 1832) and P. sajor-caju (PS 1610) on abundantly available agro-waste, bagasse, was evaluated. Three different levels of treatments were applied for each effluent. The effects of amendments on the result were observed in terms of yield, biological efficiency (BE) and substrate dry-matter loss. BE was found to be the highest (66.63 ± 1.0 %) for P. sajor-caju grown on bagasse amended with 10 % DWW and lowest for Pleurotus controls. While P. sajor-caju performed better on bagasse amended with DWW, P. flabellatus was more suited to grow on DSW amended bagasse. Degradation of complex molecules was in accordance with substrate dry-matter loss and the respective yields. The biochemical analysis of mushroom fruit bodies showed them to be a rich source of protein (maximum 36.40 %) and sugars (maximum 41.58 %). The study thus proved to be beneficial for effective management of the waste by employing higher order fungi as well as obtaining nutrient-rich delicacy for the mass.

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Development of antibiotic resistance in environmental bacteria is a direct threat to public health. Therefore, it becomes necessary to understand the fate and transport of antibiotic and its resistant bacteria. This paper presents a mathematical model for spatial and temporal transport of fluoroquinolone and its resistant bacteria in the aquatic environment of the river. The model includes state variables for organic matter, fluoroquinolone, heavy metals, and susceptible and resistant bacteria in the water column and sediment bed. Resistant gene is the factor which makes bacteria resistant to a particular antibiotic and is majorly carried on plasmids. Plasmid-mediated resistance genes are transferable between different bacterial species through conjugation (horizontal resistance transfer). This model includes plasmid dynamics between susceptible and resistant bacteria by considering the rate of horizontal resistance gene transfer among bacteria and the rate of losing resistance (segregation). The model describes processes which comprise of advection, dispersion, degradation, adsorption, diffusion, settling, resuspension, microbial growth, segregation, and transfer of resistance genes. The mathematical equations were solved by using numerical methods (implicit-explicit scheme) with appropriate boundary conditions. The development of the present model was motivated by the fact that the Musi River is heavily impacted by antibiotic pollution which led to the development of antibiotic resistance in its aquatic environment. The model was simulated for hypothetical pollution scenarios to predict the future conditions under various pollution management alternatives. The simulation results of the model for different cases show that the concentration of antibiotic, the concentration of organic matter, segregation rate, and horizontal transfer rate are the governing factors in the variation of population density of resistant bacteria. The treatment of effluents for antibiotics might be costly for the bulk drug manufacturing industries, but the guidelines can be made to reduce the organic matter which can limit the growth rate of microbes and reduce the total microbial population in the river. The reduction in antibiotic concentration can reduce the selection pressure on bacteria and can limit the population of resistant culture and its influence zone in the river stretch; however, complete removal of antibiotics may not result in complete elimination of antibiotic-resistant bacteria.

Antibiotic resistance in clinical settings has been studied from last few decades but the possibility of development of antibiotic resistance at polluted environmental sites is also of concern. In developing countries, the major source of antibiotic contamination in surface water is improper disposal of effluents from industries, hospitals and domestic waste water treatment plants. The antibiotic pollution combined with other environmental pollution factors exerts selective pressure on environmental microbes, driving evolution and resulting in the spread of antibiotic resistance in a local to global scale. Present study aimed to determine the proliferation of ciprofloxacin resistant bacteria in aquatic environment of a river which is heavily impacted by industrial effluents. Correlation analyses were performed to evaluate the impact of anthropogenic factors. Statistical analysis evaluated the effect of fluoroquinolones, heavy metals, total organic carbon and total nitrogen on the levels of resistant culture in samples from the natural settings.