Horizontal Gene Transfer Between Bacteriophages and Bacteria: Antibiotic Resistances and Toxin Production

Abstract

Antibiotic resistance genes (ARGs) are ubiquitous among microorganisms living in a wide variety of environments and can be detected by several molecular techniques. Similarly, toxins and genes encoding toxins are also widespread among organisms. Bacteriophages are bacterial viruses found wherever bacteria exist, and their concentration is particularly high in aquatic environments. The age of the “omics” truly revolutionized this field, establishing the phylogenetic affiliation and function of phages, as well as the role they play in microbial communities and horizontal transfer of bacterial genes. Genomics, transcriptomics, proteomics, and metabolomics have highlighted the role of phages and their interaction with bacterial populations. It is now generally accepted that horizontal gene transfer regularly occurs between bacteriophages and their hosts, either by generalized or specialized transductions or possibly by controlling certain bacterial populations of donors or recipients. This means that phages not only play a major role driving bacterial evolution but also influence their own evolution. Phage infection can result in the bacterial host quickly acquiring (or loosing) novel genes and thus biochemical properties, a process otherwise extremely slow that usually requires long periods of time. This chapter will focus on the role of bacteriophages in the transfer of both antibiotic resistance genes and genes encoding novel toxins to new bacterial species. This knowledge is essential not only to understand the current challenges experienced in medicine but also to prevent, or at least lessen, future clinically relevant threats resulting from gene transfer between microorganisms.