![Credit: <i>Agriculture, Ecosystems & Environment</i> (2022). DOI: 10.1016/j.agee.2022.108195″ width=”791″ height=”530″/><figcaption class= Quaternary ammonium disinfectant exposure promotes bacterial antibiotic resistance in soils](https://oponame.com/wp-content/uploads/2022/10/Exposure-to-quaternary-ammonium-disinfectants-promotes-bacterial-resistance-to-antibiotics.jpg)
As antibiotics are restricted or even banned in animal production, more disinfectants are used to maintain proper sanitation to prevent bacterial disease. The use of disinfectant exceeds that of antibiotics, especially during the influenza pandemic. Widely used quaternary ammonium disinfectants have exacerbated the problem of antimicrobial resistance due to co-resistance and cross-resistance, but disinfectant-induced antibiotic resistance changes in the soil environment are not clear.
In a study published in Agriculture, Ecosystems & Environmenta research group led by Professor Yao Huaiying and Professor Su Jianqiang from the Institute of Urban Environment of the Chinese Academy of Sciences has made progress in understanding exposure to concentration gradient disinfectants. quaternary ammonium induced co-selection of soil antibiotic resistome.
“The appropriate concentration of disinfectant is one of the key factors in the selection of resistant bacteria. Concentrations at the environmental level, in particular, require special attention,” Professor Yao said.
A short-term soil microcosm was established to study the dynamics of the antibiotic resistance gene (ARG) profile in agricultural soils amended with sulfamethazine (SMZ, 10 mg kg-1) and concentration gradients of benzalkonium chloride (0, 1, 10, 100 mg kg-1BC(C12), a widely used class of quaternary ammonium disinfectants).
A unique concentration effect on changes in ARG profiles in agricultural soils exposed to different BC concentrations was found. With increasing BC concentration, the number of ARGs detected in the soil increased, while the total ARG abundance decreased.
The highest number of ARGs was observed during exposure to high concentrations of BC. Won’t a high concentration of disinfectant directly damage bacteria? The researchers hypothesized that this phenomenon is related to the adsorption and storage of BC in the soil.
Quaternary ammonium disinfectants are cationic surfactants, and their high adsorption affinity for soil particles will cause their bioavailability to decrease, thereby reducing their mineralization and acute toxicity. However, adsorption and isolation from soil increase the persistence of BC, and the gradual release of BC induces the appearance of greater antibiotic resistance.
“Co-selection for antimicrobial resistance only occurs when concentrations of bioavailable disinfectants are below the critical biocidal concentration,” Professor Yao said. “The complexity of the soil environment and the effect of disinfectant concentration combined to develop soil ARG profiles.”
SMZ was added by the researchers to investigate whether SMZ and BC would synergistically promote the co-selection of soil ARGs in the context of combined pollution. Unexpectedly, SMZ and BC had no obvious interaction in forming the ARG profile in the soils. Compared to that of broad-spectrum BC fungicide, the specificity of SMZ significantly affected the microbial community. SMZ mainly affected the vertical gene transfer of ARGs by altering the abundance of the bacterial host.
This work contributes to future public health risk assessments related to antibiotic resistance induced by quaternary ammonium disinfectants. Disinfectants end up in surface water or soil via sewer lines and fertilizing manure. Dilution and degradation result in environmental levels well below those used at the point of application. “Future research still needs to focus on the lower BC concentration range,” said Professor Su.
Single-cell tools provide insight into active antibiotic resistome in soils
Haiyang Yu et al, A meta-analysis of ecological functions and economic benefits of co-cultivation models in rice fields, Agriculture, Ecosystems & Environment (2022). DOI: 10.1016/j.agee.2022.108195
Provided by Chinese Academy of Sciences
Quote: Exposure to quaternary ammonium disinfectant promotes bacterial resistance to antibiotics in soils (October 17, 2022) retrieved on October 17, 2022 from https://phys.org/news/2022-10-quaternary-ammonium-disinfectant -exposure-bacterial.html
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