However, many interactions between organisms and cells depend on being able to sense and react with chiral molecules in the first place. Their incompatibility with natural biological reactions would leave mirror bacteria with no natural predators in the wild, as they could not be sensed, killed, or digested by bacteriophages or other organisms. Crucially, many of the immune responses in humans, other animals, and plants also work by sensing and reacting with chiral bacterial molecules. If a human were to be infected with mirror bacteria, it could be as if they were immunocompromised, as their immune systems would face great difficulty in detecting or killing the mirror cells. As a result, mirror bacteria could hypothetically replicate to extremely high levels in the human body, causing conditions similar to septic shock.
The downside of having a biology that renders mirror bacteria ‘invisible’ to natural enemies is that they would not be able to consume many of the chiral nutrients found in nature. However, several nutrients, such as glycerol, are achiral (they do not have mirrored forms), and thus could be consumed by mirror bacteria. Well-intentioned scientists could also engineer mirror bacteria that can consume naturally occurring chiral molecules such as sugars and amino acids.
In turn, mirror bacteria could spread throughout the environment without natural predators, infect organisms without triggering much of their immune response, and possibly cause fatal infections. An unstoppable replicating mirror bacteria free in the environment could cause consequences that are disastrous.
