Occurrence and prevalence of antibiotic resistance genes and pathogens in an industrial park wastewater treatment plant.

Antibiotic resistance genes (ARGs) and pathogens are emerging environmental pollutants that pose a threat to human health and ecosystem. Industrial park wastewater treatment plants (WWTPs) treat large amounts of comprehensive wastewater derived from industrial production and park human activity, which is possible a source of ARGs and pathogens. Therefore, this study investigated the occurrence and prevalence of ARGs, ARGs hosts and pathogens and assesses the ARGs health risk in the biological treatment process in a large-sale industrial park WWTP using metagenomic analysis and omics-based framework, respectively. Results show that the major ARG subtypes are multidrug resistance genes (MDRGs), macB, tetA(58), evgS, novA, msbA and bcrA and the ARGs main hosts were genus Acidovorax, Pseudomonas, Mesorhizobium. In particular, all determined ARGs genus level hosts are pathogens. The total removal percentage of ARGs, MDRGs and pathogens were 12.77 %, 12.96 % and 25.71 % respectively, suggesting that the present treatment could not efficiently remove these pollutants. The relative abundance of ARGs, MDRGs and pathogens varied along biological treatment process that ARGs and MDRGs were enriched in activated sludge and pathogens were enriched in both secondary sedimentation tank and activated sludge. Among 980 known ARGs, 23 ARGs (e.g., ermB, gadX and tetM) were assigned into risk Rank I with characters of enrichment in the human-associated environment, gene mobility and pathogenicity. The results indicate that industrial park WWTPs might serve as an important source of ARGs, MDRGs, and pathogens. These observations invite further study of the origination, development, dissemination and risk assessment of industrial park WWTPs ARGs and pathogens.

Viral community in landfill leachate: Occurrence, bacterial hosts, mediation antibiotic resistance gene dissemination, and function in municipal solid waste decomposition.

A municipal solid waste (MSW) landfill is a significant source of antibiotic resistance, pathogens and viruses and also a habitat for microbial consortia that perform MSW decomposition. Viruses are of great significance in ecological interactions such as MSW decomposition and antibiotic resistance gene (ARG) transmission. In this study, the viral community structure and the associated driver, the linkage of viruses and their bacterial hosts, the virus-associated ARG dissemination and virtual community function on MSW decomposition were investigated in landfill leachate from seven cities, China. The seven cities include four megacities, two large-scale cities and one small-scale city, representing the leachate characters of China. The results showed that the leachates were dominated by the phage families Siphoviridae, Myoviridae and Podoviridae (91.7 ± 3.6) %. Their putative hosts were the important MSW decomposers Lactobacillus, Pseudomonas, Clostridium, Proteiniphilum, and Bacteroides. The structure of the viral community was significantly affected by pH (P = 0.007, analyzed by RDA) and the bacterial community (R = 0.83, P < 0.001, analyzed by Mantel test). The relative abundance of ARGs showed a strong correlation (R > 0.8, P < 0.01) with viral family, suggesting that viruses play an important role in ARGs dissemination. Phage regulate bacterial population abundance through top-down effects, thus participating in MSW decomposition. These results demonstrate that viral community are involve in ARGs transmission and dissemination and mediate MSW decomposition in landfill.