Occurrence Of The Co-Selection Phenomenon In Non-Clinical Environments

Multi-resistant bacterial strains currently present the main health problem worldwide. Numerous public health organizations call for the prevention, and control the spread, of antibiotic resistance from any sources. From the literature data, it is well known that agricultural areas are a source of antibiotic resistance because of the use of antibiotics and heavy metals to promote plant and animal growth. Moreover, natural water reservoirs and soil not used for agriculture are also sources of multi-drug resistant bacteria. In recent years bacteria resistant to antibiotics and heavy metals have been isolated from heavy-metal contaminated soils and from metallophytes. Therefore, it seems that heavy metals, an environmental pollutant, may also be a selection factor that promotes the spread of antibiotic resistance. The co-selection phenomenon of resistant genes is most often connected with the lack of bacterial susceptibility to antibiotics and heavy metals. Co-selection occurs when different resistant genes that enable resistance to different stress conditions are located on the same mobile genetic elements, or when the same genes determine resistance to different stress conditions. This article presents the current state of knowledge about the co-selection phenomenon observed in bacteria isolated from nonclinical environments.

1. Introduction. 2. Co-selection mechanisms. 2.1. Cross-resistance. 2.2. Co-resistance. 2.3. Co-regulation. 3. Factors promoting spread of co-selection. 4. Occurrence of co-selection in non-clinical environments. 4.1. Areas used for agriculture. 4.2. Areas not used agriculturally. 4.3. Natural water reservoirs. 4.4. Plant endosphere. 5. Co-occurence of resistant genes in different environmental genomes. 6. Summary