Molecular detection of resistance and transfer genes in environmental samples

Abstract

Horizontal plasmid transfer is the most important means of spreading resistance to antibiotics and heavy metals, as well as virulence genes, to closely and remotely related microorganisms thereby increasing the horizontal gene pool in so diverse habitats such as soils, wastewater, aquifer recharge systems and glacier ice. An overview about the currently used molecular tools to detect and quantify the abundance of antibiotic and heavy metal resistance and transfer genes in aquatic and terrestrial environments is provided. Habitats studied range from nutrient rich environments such as manured agricultural soils to oligotrophic habitats such as drinking water or glaciers in the Antarctic. The state of the art in antibiotic and heavy metal resistance mechanisms and monitoring of conjugative transfer factors to assess the transmissibility of the resistance factors is summarized. The chapter ends with perspectives on emerging new molecular monitoring tools suited to rapid, reliable and high throughput analysis of environmental samples differing in origin and level of pollution.