Bacteria control their own growth in response to environmental challenges. Growth-arrested bacteria often show remarkable abilities to survive exposure to antibiotics and are called antibiotic persisters. Persister cells are multidrug tolerant bacteria that can survive extended periods of time in their infected host and are thought to be responsible for the recalcitrance of many infections to antibiotic treatment, including those caused by Mycobacterium tuberculosis, Salmonella species, Pseudomonas aeruginosa and pathogenic Escherichia coli.
The eventual resumption of growth by persisters may account for relapses and the need for recurring therapy, and persistence has been shown to be a stepping-stone towards the development of antibiotic resistance. There is therefore a pressing need to understand the formation, physiology, survival and impact of persisters during infection so that effective ways to clear them can be identified.