Sethi, J. | Search bioRxiv

bioRxiv2020

Effect of earthworms in removal and fate of Antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) during clinical laboratory wastewater treatment by vermifiltration

The wastewater treatment plants effluent has been implicated in the spread of antibiotic resistant bacteria (ARB) as these environment contains multiple selective pressures that may increase mutation rates, pathogen survivability, and induce gene transfer between bacteria. In lieu of this, the present study explored the dynamics of earthworm-microorganisms interactions on the treatment efficacy of clinical laboratory wastewater treatment by vermifiltration and the effect of earthworms in the fate of removal of pathogens and ARB. The results of the study showed that earthworms and VF associated microbial community had a significant effect on BOD and COD reduction (78-85%), pathogen removal (>99.9 %) and caused a significant shift in the prevalence pattern of ARB. Additionally, molecular profiling of ESBL (blaSHV, blaTEM and blaCTX-M), MRSA (mec-A) and Colistin (mcr-1) gene confirmed the probable mechanisms behind the resistance pattern. The microbial community diversity assists in the formation of biofilm, which helps in the removal of pathogens and results in a paradigm shift in the resistance profile of ARB and ARG, specifically most effective against drugs, targeting cell wall and protein synthesis inhibition like Ampicillin, Ticarcillin, Gentamicin and Chloramphenicol. These findings prove vermifiltration technology as a sustainable and natural treatment technology for clinical laboratory wastewater.

ecology↗

bioRxiv2020

Design, Performance Evaluation and Investigation of the Dynamic Mechanisms of Earthworm-Microorganisms interactions for wastewater treatment through Vermifiltration technology

The present study points to the relevance of the earthworms-microorganisms symbiotic and synergistic interactions that drive the wastewater treatment by identifying the most essential mechanisms underlying the removal of contaminants during vermifiltration technology. Previous studies have showed the presence of earthworms improves treatment performance of vermifilter (VF), but earthworm microbial community dynamics, their structure and functional characteristics in VF were not fully investigated. To investigate the effects of earthworms on the inherent microbial community of the VF, the present study envisages the dynamics of the complex symbiosis of earthworms & microorganisms associated to the treatment mechanisms. In this study, the design, operations and performance evaluation and influent, effluent and filter media layer were investigated for microbial diversity inside the earthworm population, along with the antimicrobial activity, enzymatic activity, and protein profiling assays. The results showed that earthworm gut microbial communities were dominated by Gammaproteobacteria, and the percentages arrived to 59-60% of the microbial species detected, while filter media layer showed presence of Firmicutes and Actinobacteria. The protein profiling of the microbiota associated with the VF showed that earthworms feeding and earthworm-microorganism interaction were responsible for enhanced treatment performance. The finding provides an insight into the complex earthworm microbial dynamics and mechanisms for wastewater treatment in VF. Furthermore, earthworm predation strongly regulated microbial biomass while improving microbial activity, and is deciphered as the possible mechanisms behind the vermifiltration technology.

ecology↗