Abstract
For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.
Highlights
Generalized detection techniques typically fail to detect dormant cells, and we review the various reasons for this failure and discuss alternatives (8)
We show the same from patients with hereditary hemochromatosis (Figure 7C) and type 2 diabetes (Figure 7D)
In many diseases it is considered that patients with the disease are more prone to sepsis, but we suggest here that it may more likely be the converse that is truer: patients suffering from latent infections are more prone to acquiring, having, or exacerbating the state of these other conditions, in a vicious cycle
Summary
The problem of anabiosis or latent life: history and current concept. Proc R Soc Lond B Biol Sci. 1959; 150(939): 149–91. 2. Kaprelyants AS, Gottschal JC, Kell DB: Dormancy in non-sporulating bacteria.
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