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Chapter 19 : Selective Agencies
This chapter highlights the fact that selective pressures can be fostered by agents other than antimicrobials. Peter Gilbert and coworkers at Manchester University in the United Kingdom found that several seemingly innocuous culinary herbs, for example, induced mar expression in Escherichia coli. While the practical implications of this finding remain to be clarified, the discovery underlines the fact that much remains to be learned despite decades of intensive scrutiny of antibiotic resistance. The last few years have also seen reports that chemotherapeutic drugs, such as clofibric and ethacrynic acids, as well as chemicals, including sodium salicylate and sodium benzoate, induce the Mar phenotype in Escherichia coli by activating the marRAB operon. Copper, referred to as an agent, is used in several forms as an agricultural fungicide and bactericide but also occurs in the sewage sludge and animal manure that farmers in many places spread on their fields as fertilizer. Unlike many other pollutants, copper is not degraded, so the phenomenon would be long lasting. This chapter also explains that copper can be added to the soil not only selected for Copper-resistant organisms, but also coselected for antibiotic resistance. In recent years organic farmers have rejected the use of modern, safe, thoroughly tested pesticides as they are permitted to spray their crops with copper sulfate.
Key Concept Ranking
- Outer Membrane Proteins