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Antibiotic Resistance of Staphylococcus Aureus: a Review
Published in Megh R Goyal, Sustainable Biological Systems for Agriculture, 2018
Divya Lakshminarayanan, Jessen George, Suriyanarayanan Sarvajayakesavalu
The antibiotics basically target cell wall synthesis, protein synthesis; the selection pressure applied by the antibiotics that used in clinical and agricultural settings has promoted the evolution and spread of genes that confer resistance.1 Development of antibiotic resistance is conferred by mutation and selection by medical antibiotics, resistance can occur in organism by the acquisition of a novel antibiotic resistance gene by horizontal gene transfer (HGT) has a relevant role in emergence, through conjugation, transformation, or transduction through various mobile genetic elements like plasmids, transposons, integrons and so forth.13, 29 Internal mechanisms include mutational modification of gene targets, over expression of various efflux pumps; whereas acquired resistance involves enzymatic inactivation of the drug and bypassing of the target. Practices like application of sewage sludge and manure may introduce complex mixtures of bacteria containing drug resistance genes, veterinary and medical antibiotics, and other chemicals to land, where interactions may occur with indigenous soil bacteria.29
The Importance of Microbes in Organic Matter Composting
Published in Gustavo Molina, Zeba Usmani, Minaxi Sharma, Abdelaziz Yasri, Vijai Kumar Gupta, Microbes in Agri-Forestry Biotechnology, 2023
Zimin Wei, Junqiu Wu, Xiaomeng Chen, Haishi Qi, Mingzi Shi, Yufeng Chen, Yue Zhao, Xu Zhang, Xinyu Xie
Clinically, mobile genetic elements can gather various antibiotic resistance genes and spread to bacteria and environment, thus the integron gene is usually regarded as a pollutant from the DNA perspective (Gillings, 2018). The mobile genetic elements cannot transfer horizontally directly among microorganisms, but they can transfer among microorganisms (within or among species) with other genetic elements as carriers, such as plasmids, transposons and insertion sequences (Wang et al., 2015; Zhang et al., 2016b; Zhang et al., 2016c). Our previous study showed the removal rate of IntI1 and IntI2 was significantly higher during CMs composting than that of bovine manures composting (P < 0.05), which was due to the difference between food and intestinal bacteria of animals (Zhu et al., 2019). As intI1 and intI2 are common gene capture systems in bacterial genome (Gillings, 2014), the removal of intI1 and intI2 is closely related to the change of host bacteria during composting (Su et al., 2015). In general, the variation of potential host bacteria of mobile genetic elements can be divided into three categories during composting. The first type is eliminated during the thermophilic period of composting, which indicated that high temperature could kill or inhibit such host bacteria. Previous studies have also shown that high temperature composting helps to control antibiotic resistance genes and mobile genetic elements by eliminating their host bacteria (Liao et al., 2017). The second type of host bacteria begin to disappear during the cooling or maturity stage of composting. The third group of host bacteria cannot be eliminated by composting, which indicates that this kind of host bacteria has strong tolerance to high temperature, such as the phylum Proteobacteria. Many studies have shown that the Proteobacteria is the host of resistance genes. The Proteobacteria is a phylum mainly existing in the later stage of composting. The presence of these stubborn host bacteria leads to the incomplete removal of mobile genetic elements during composting. Therefore, the eradication of host bacteria is still an important way to control mobile genetic elements. In our previous study, projection pursuit models were used to evaluate the horizontal transfer risk of antibiotic resistance genes during composting (Zhu et al., 2019). The results showed that, in general, composting process can reduce the risk of antibiotic resistance gene transfer. The transfer risk decreased more sharply during CMs composting; however, the risk change of bovine manures composting was relatively slow, which was related to the change trend of host bacteria.
Characteristics and driving factors of antibiotic resistance genes in aquaculture products from freshwater ponds in China Yangtze River Delta
Published in Environmental Technology, 2023
Yiqin Chen, Bin Jia, Juan-Ying Li, Dan Li, Wenhui He
The enriched ARGs in aquaculture environments can be spread among different bacterial strains through the horizontal gene transfer (HGT) process in the microbial ecosystem, thereby rapidly spreading bacterial resistance [10]. The HGT of ARGs is mediated by various mobile genetic elements (MGEs) (plasmids, transposons and integrons, etc.), via binding, transduction and transformation [11]. Integrons (i.e. int1) are genetic fragment that allow bacteria to adapt and evolve rapidly through the stockpiling and expression of new genes. Transposons, such as tnpA, IS613 and Tp614, can insert their genes into any sequence in the genome, therefore, transposons carrying ARGs in bacteria can transfer horizontally between different strains, accelerating ARGs spread in an aquaculture environment [12]. Previous studies on the guts of fish and shrimps [13–16] showed that MGEs were ubiquitous in the guts of aquatic organisms and were significantly associated with the abundance of ARGs. Therefore, it is necessary to evaluate the HGT of ARGs in aquaculture products cultured in freshwater pond from the Yangtze River Delta region and to assess the potential risks of ARGs transmission.
Predicting algorithm of attC site based on combination optimization strategy
Published in Connection Science, 2022
Zhendong Liu, Xi Chen, Dongyan Li, Xinrong Lv, Mengying Qin, Ke Bai, Zhiqiang He, Yurong Yang, Xiaofeng Li, Qionghai Dai
In this paper, we study based on the bacterial integration subsystem. The bacterial integration system is an important application of site-specific recombination, which can capture and express foreign gene cassettes and convert them into functional gene expression units by site-specific recombination (Domingues et al., 2012). Through the recombination of DNA fragments between sites, bacteria can acquire properties that are beneficial to themselves, such as increasing bacterial resistance. Studies have shown that integron-promoted horizontal gene transfer enables bacteria to acquire foreign drug resistance genes as an important reason for accelerating the spread of clinically relevant Gram-negative pathogens(Mazel et al., 2015; Stalder et al., 2012). The function of the integron depends on the activity of the integrase (Nivina et al., 2016; Weiss et al., 2019), which is a site-specific tyrosine recombinase with the special ability to excise, integrate, reverse and translocate DNA fragments in organisms. Gene cassettes are usually mobile elements that carry a single gene and an associated recombination site (attC). Investigation shows that many gene cassettes often carry antibiotic resistance genes. Gene cassettes can exist independently in the form of a free ring, or they can be recognised and catalysed by integrases, and site-specific recombination becomes a part of the integron structure (Ghaly et al., 2021; Vit et al., 2020).
Multidrug resistance and class 1 integron presence in Escherichia coli isolates from a polluted drainage ditch’s water
Published in International Journal of Environmental Health Research, 2022
Yesmi Patricia Ahumada-Santos, Francisco Delgado-Vargas, María Elena Báez-Flores, Gabriela López-Angulo, Sylvia Páz Díaz-Camacho, Monika Moeder, Jesús Ricardo Parra-Unda
Integrons are genetic elements associated with plasmids and transposons, and they are involved in horizontal gene transfer between pathogenic and commensal bacteria. The main structural elements of an integron are recombination site (attI), promoter (Pc), the integrase gene (intI) that catalyzes recombination between the attC site of circular gene cassettes, and the attendant recombination site (attI). The amino acid sequences of intI define the class of integrons (Gillings et al. 2015; Zhang et al. 2020). The intI1 gene has been considered a good proxy for anthropogenic pollution (Gillings et al. 2015). The class 1 integrons are involved in the spread of antimicrobial resistance (AMR) by the acquisition and dissemination of antibiotic resistance genes (Gillings 2018), representing a risk to human health (Zhang et al. 2020).