FIG 7.

Uncharted epigenetic mechanisms and their putative role in antibiotic resistance. Some epigenetic mechanisms are putatively associated with antibiotic resistance but remain poorly documented or partially understood. When methyltransferase-encoding phages infect bacteria, the phage DNA encoding methyltransferases (Mtases) can get integrated into the bacterial genome and influence the methylomes of the daughter cells. The link between altered methylomes and antibiotic resistance has been proposed by several groups, but direct evidence for this hypothesis is still lacking (left box). Epigenetic regulation of expression of genes that are not directly associated with antibiotic resistance has been predicted to contribute to the resistant phenotype, but the underlying mechanisms are poorly understood (right box).