Influence of pollutants on the spread of antibiotic resistance genes in the environment

The development of antibiotic resistant bacteria (ARB) is one of the most significant problems in modern medicine and poses a serious threat to human health. Understanding the ecology of resistance genes is extremely difficult, since genes can be carried by uncultivated bacteria. It has been shown that introduction of pollutants into the environment contributes to the active selection of ARB and antibiotic-resistance genes (ARG). Antibiotics stimulate reproduction of ARB and selection of ARG. Resistance to heavy metals and antibiotics is achieved by the same mechanisms, which leads to the selection of ARG in environments contaminated with heavy metals. Bacteria can decompose polyaromatic hydrocarbons (PAH) or use them as a source of nutrients. Bacteria that are unable to decompose PAHs to fewer toxic products use various mechanisms to remove polyaromatic hydrocarbons from cells. Thus, with the help of efflux pumps, not only PAHs can be removed from cells, but also antibiotics or heavy metals, which leads to the emergence of ARG. The factor in the joint selection of ARG, resistance to heavy metals, and PAHs biotransformation genes is also their joint localization on mobile genetic elements. Resistance genes to metals and ARG are often a part of the same plasmids. For genes of hydrocarbon biodegradation pathways, transmission is shown using type I integrons, which also often transmit multidrug resistance. Resistance to pesticides occurs as the result of mutation. The mutated enzyme may be able to decompose not only pesticides, but also antibiotics. Microplastics are hydrophobic and capable of adsorbing a variety of pollutants. Large particles of microplastics promote the spread of antibiotic resistance genes. Multiple antibiotic resistance is an important public health issue. Understanding the mechanisms of emergence and spread of ARG may help to solve this problem.