Abortive Infection

∞ generated and posted on 2023.05.16 ∞

Viral entry resulting in both bacterial and phage death.

Abortive Infections are one means by which bacteria can inhibit the infection by phages, though this is a means that comes at a very high cost to the phage infected bacterium.

Phage exclusion is sometimes used as a synonym to abortive infection.

Note that assuming both phage and bacterial death is a fairly strict definition of abortive infection. Less strictly, the concept of phage abortive infection may imply phage bactericidal activity in combination with low phage efficiency of plating (EOP). Efficiency of plating, though, can be low for reasons other than phage inviability, such as due to new phage production at rates that are too low to lead to the formation of plaques..

The definition from Adams (1959), p. 439: , by contrast, strictly assumes phage death but not necessarily also bacterial death:

Infection accompanied by loss of the infecting phage particle and often death of the bacterium but not yielding a phage progeny under normally sufficient conditions. Infection is abortive because of unusual conditions prevailing before, at the time of, or shortly after infection.

Lwoff (1953), p. 328, provided a slightly different definition that also did not require death of the infected bacterium:

Infection followed neither by lysogenization nor by phage production. The infecting material is not reproduced. A bacterium may or may not survive an abortive infection.

Thus, it is possible to define abortive infection in manners that require neither bacterial nor phage death upon phage infection, with older definitions requiring phage death but not necessarily bacterial death while newer more operational definitions, as based on lower efficiency of plating, do not necessarily strictly require even phage death.

It is possible to confirm phage death, however, using efficiency of center of infection assays rather than efficiency of plating assays, and also that low phage efficiency of plating certainly does not imply death of phage infected bacteria.

Abortive Infections in any case can be a consequence of phage defects (i.e., phage mutations or instead phage nucleic acid damage), genetic incompatibilities between a wild-type infecting phage and an adsorbed bacterium to support a productive phage infection.

A related but not identical phenomenon to abortive infection is lysis from without. It is important to recognize, however, that not all abortive infections, even if associated with high phage multiplicities of adsorption, are necessarily a consequence of lysis from without.

For additional discussion of abortive infections, click here. Contrast in part with productive phage infection.

Next | Previous phage therapy-related terms: Active Infection | Virus Particle.

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