scholarly journals Constructed Wetland Revealed Efficient Sulfamethoxazole Removal but Enhanced the Spread of Antibiotic Resistance Genes

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 834 ◽  
Author(s):  
Shuai Zhang ◽  
Yu-Xiang Lu ◽  
Jia-Jie Zhang ◽  
Shuai Liu ◽  
Hai-Liang Song ◽  
...  

Constructed wetlands (CWs) could achieve high removal efficiency of antibiotics, but probably stimulate the spread of antibiotic resistance genes (ARGs). In this study, four CWs were established to treat synthetic wastewater containing sulfamethoxazole (SMX). SMX elimination efficiencies, SMX degradation mechanisms, dynamic fates of ARGs, and bacterial communities were evaluated during the treatment period (360 day). Throughout the whole study, the concentration of SMX in the effluent gradually increased (p < 0.05), but in general, the removal efficiency of SMX remained at a very high level (>98%). In addition, the concentration of SMX in the bottom layer was higher compared with that in the surface layer. The main byproducts of SMX degradation were found to be 4-amino benzene sulfinic acid, 3-amino-5-methylisoxazole, benzenethiol, and 3-hydroxybutan-1-aminium. Temporally speaking, an obvious increase of sul genes was observed, along with the increase of SMX concentration in the bottom and middle layers of CWs. Spatially speaking, the concentration of sul genes increased from the surface layer to the bottom layer.

2020 ◽  
Vol 194 ◽  
pp. 04010
Author(s):  
Zhuma Luosang ◽  
Wanjun Zhang ◽  
Junwen Ma ◽  
fengying Huang ◽  
Yubo Cui

The in-situ static box method was used to conduct a comparative experiment on sludge treatment wetlands (STWs). STW1 had ventilation structure, without reeds and STW2 had ventilation and was planted with reeds. The absolute abundance of sulfonamide, tetracycline and macrolide antibiotic resistance genes (ARGs) in the two STWs were analyzed, and the paper discussed pollution characteristics of typical antibiotic resistance genes in the two STWs. The results showed that three ARGs, sul1 (sulfonamides), tetC (tetracyclines), ermf (macrolides), were detected in STW1 and STW2. The concentration of arginine was sul1 > tetC > ermf. The concentration level of AGRS in STW1 and STW2 was lower in bottom layer than that of surface layer sludge. The removal efficiency of ARGs in the same system was tetC > sul1 > ermf, and the removal efficiency of surface sludge and bottom sludge in different systems was STW2 > STW1. Planting wetland plants in the STW can promote the removal of ARGs.


Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 378
Author(s):  
Inka Marie Willms ◽  
Maja Grote ◽  
Melissa Kocatürk ◽  
Lukas Singhoff ◽  
Alina Andrea Kraft ◽  
...  

Antibiotic resistance genes (ARGs) in soil are considered to represent one of the largest environmental resistomes on our planet. As these genes can potentially be disseminated among microorganisms via horizontal gene transfer (HGT) and in some cases are acquired by clinical pathogens, knowledge about their diversity, mobility and encoded resistance spectra gained increasing public attention. This knowledge offers opportunities with respect to improved risk prediction and development of strategies to tackle antibiotic resistance, and might help to direct the design of novel antibiotics, before further resistances reach hospital settings or the animal sector. Here, metagenomic libraries, which comprise genes of cultivated microorganisms, but, importantly, also those carried by the uncultured microbial majority, were screened for novel ARGs from forest and grassland soils. We detected three new beta-lactam, a so far unknown chloramphenicol, a novel fosfomycin, as well as three previously undiscovered trimethoprim resistance genes. These ARGs were derived from phylogenetically diverse soil bacteria and predicted to encode antibiotic inactivation, antibiotic efflux, or alternative variants of target enzymes. Moreover, deduced gene products show a minimum identity of ~21% to reference database entries and confer high-level resistance. This highlights the vast potential of functional metagenomics for the discovery of novel ARGs from soil ecosystems.


2009 ◽  
Vol 76 (4) ◽  
pp. 1095-1102 ◽  
Author(s):  
Nelly Dubarry ◽  
Wenli Du ◽  
David Lane ◽  
Franck Pasta

ABSTRACT The bacterium Burkholderia cenocepacia is pathogenic for sufferers from cystic fibrosis (CF) and certain immunocompromised conditions. The B. cenocepacia strain most frequently isolated from CF patients, and which serves as the reference for CF epidemiology, is J2315. The J2315 genome is split into three chromosomes and one plasmid. The strain was sequenced several years ago, and its annotation has been released recently. This information should allow genetic experimentation with J2315, but two major impediments appear: the poor potential of J2315 to act as a recipient in transformation and conjugation and the high level of resistance it mounts to nearly all antibiotics. Here, we describe modifications to the standard electroporation procedure that allow routine transformation of J2315 by DNA. In addition, we show that deletion of an efflux pump gene and addition of spermine to the medium enhance the sensitivity of J2315 to certain commonly used antibiotics and so allow a wider range of antibiotic resistance genes to be used for selection.


2020 ◽  
Vol 8 (9) ◽  
pp. 1293
Author(s):  
Pedro Blanco-Picazo ◽  
Gabriel Roscales ◽  
Daniel Toribio-Avedillo ◽  
Clara Gómez-Gómez ◽  
Conxita Avila ◽  
...  

Anthropogenic activities are a key factor in the development of antibiotic resistance in bacteria, a growing problem worldwide. Nevertheless, antibiotics and resistances were being generated by bacterial communities long before their discovery by humankind, and might occur in areas without human influence. Bacteriophages are known to play a relevant role in the dissemination of antibiotic resistance genes (ARGs) in aquatic environments. In this study, five ARGs (blaTEM, blaCTX-M-1, blaCTX-M-9, sul1 and tetW) were monitored in phage particles isolated from seawater of two different locations: (i) the Mediterranean coast, subjected to high anthropogenic pressure, and (ii) the Antarctic coast, where the anthropogenic impact is low. Although found in lower quantities, ARG-containing phage particles were more prevalent among the Antarctic than the Mediterranean seawater samples and Antarctic bacterial communities were confirmed as their source. In the Mediterranean area, ARG-containing phages from anthropogenic fecal pollution might allow ARG transmission through the food chain. ARGs were detected in phage particles isolated from fish (Mediterranean, Atlantic, farmed, and frozen), the most abundant being β-lactamases. Some of these particles were infectious in cultures of the fecal bacteria Escherichia coli. By serving as ARG reservoirs in marine environments, including those with low human activity, such as the Antarctic, phages could contribute to ARG transmission between bacterial communities.


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