scholarly journals Extended spectrum β-lactamase and carbapenemase genes are substantially and sequentially reduced during conveyance and treatment of urban sewage

2020 ◽  
Author(s):  
Liguan Li ◽  
Joseph Nesme ◽  
Marcos Quintela-Baluja ◽  
Sabela Balboa ◽  
Syed Hashsham ◽  
...  

AbstractIntegrated and quantitative observations of antibiotic resistance genes (ARGs) in urban water systems (UWSs) are lacking. We sampled three UWSs for clinically important extended spectrum β-lactamase (ESBL) and carbapenemase (CP) genes, mobile genetic elements and microbial communities. Sewage – especially from hospitals – carried substantial loads of ESBL and CP genes (106 – 107 per person equivalent), but those loads progressively declined along the UWS, resulting in minimal emissions (101 – 104 copies per person equivalent). Removal was primarily during sewage conveyance (65% ± 36%) rather than within sewage treatment (34% ± 23%). The ARGs clustered in groups based on their persistence; less persistent groups were associated to putative host taxa (especially Enterobacteriaceae and Moraxellaceae), while more persistent groups appear horizontally transferred as they correlated with mobile genetic elements. This first documentation of a substantial ARG reduction during sewage conveyance provides opportunities for antibiotic resistance management and a caution for sewage-based ARG surveillance.

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5428
Author(s):  
Yanli Fu ◽  
Aisheng Zhang ◽  
Tengfei Guo ◽  
Ying Zhu ◽  
Yanqiu Shao

Sewage treatment plants are known as repositories of antibiotic resistance genes (ARGs). Adding biochar and inoculating with exogenous microbial agents are common ways to improve the quality of compost. However, little is known about the effects of these exogenous additives on the fate of ARGs during composting and the related mechanisms. In this study, municipal sludge was taken as the research object to study the ARG-removal effects of four composting methods: ordinary compost (CT), compost with hyperthermophiles (HT), compost with hyperthermophiles and 2.0% biochar (HT2C) and compost with hyperthermophiles and 5.0% biochar (HT5C). Real-time quantitative PCR (qPCR) and 16S rRNA high-throughput sequencing were conducted to analyze the ARGs, MGEs and bacterial community. After composting, the abundance of ARGs in CT was reduced by 72.7%, while HT, HT2C and HT5C were reduced by 80.7%, 84.3% and 84.8%, respectively. Treatments with different proportions of biochar added (HT2C, HT5C) had no significant effect on the abundance of ARGs. Network analysis showed that Firmicutes and Nitrospirae were positively associated with most ARGs and may be potential hosts for them. In addition, redundancy analysis further showed that the class 1 integrase gene (intI1), pH and organic carbon had a greater effect on ARGs. Our findings suggested that the combination of hyperthermophiles and biochar during the composting process was an effective way to control ARGs and mobile genetic elements (MGEs), thus inhibiting the spread and diffusion of ARGs in the environment and improving the efficiency of treating human and animal diseases.


2016 ◽  
Vol 106 ◽  
pp. 62-70 ◽  
Author(s):  
Junya Zhang ◽  
Qianwen Sui ◽  
Juan Tong ◽  
Chulu Buhe ◽  
Rui Wang ◽  
...  

2018 ◽  
Author(s):  
Jean Cury ◽  
Pedro H. Oliveira ◽  
Fernando de la Cruz ◽  
Eduardo P.C. Rocha

AbstractSelf-transmissible mobile genetic elements drive horizontal gene transfer between prokaryotes. Some of these elements integrate in the chromosome, whereas others replicate autonomously as plasmids. Recent works showed the existence of few differences, and occasional interconversion, between the two types of elements. Here, we enquired on why evolutionary processes have maintained the two types of mobile genetic elements by comparing integrative and conjugative elements (ICE) with extrachromosomal ones (conjugative plasmids) of the highly abundant MPFT conjugative type. We observed that plasmids encode more replicases, partition systems, and antibiotic resistance genes, whereas ICEs encode more integrases and metabolism-associated genes. ICEs and plasmids have similar average sizes, but plasmids are much more variable, have more DNA repeats, and exchange genes more frequently. On the other hand, we found that ICEs are more frequently transferred between distant taxa. We propose a model where differential plasticity and transmissibility range explain the co-occurrence of integrative and extra-chromosomal elements in microbial populations. In particular, the conversion from ICE to plasmid allows ICE to be more plastic, while the conversion from plasmid to ICE allows the expansion of the element‘s host range.


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