Chemical ‘death screams’ of bacteria help invading swarm survive antibiotics

Invading bacteria let out a “death scream” when they die – warning parts of the nearby swarm about potential dangers that face them, new research has found.

While the screams can not be heard, the chemical alarm is able to send out warnings as the bacteria sits on the edge of death in an action called necrosignalling.

This necrosignalling happens when the bacteria face a major threat to their existence, such as from antibiotics in the hope that enough survivors would be able to mutate and become resistant to them.

The study published earlier this month in the science journal Nature Communications said: “Bacterial swarms are metabolically active and grow robustly.”

Because of that, scientists suspected that the swarms could also have their own mechanisms for evolving antibiotic resistances that would differ from other bacteria.

Researchers found when an invading swarm came across antibiotics that some 25% of them died, but that the survivors were able to hold on due to the necrosignalling.

It is unclear what guided the bacteria to behave in such a way, however.

A fresh study looked at swarms of E.coli bacteria as they interacted with antibiotics in a bid to uncover how the dead cells might have saved the rest of them.

The experts found that when the necrosignal was detected by the rest of the swarm, they moved away from the presence of the danger.

It also activated parts of the cells’ live membranes “to start pumping out the antibiotics”, the University of Texas at Austin professor Rasika Harshey told Live Science.

Dr Harshey added: “Dead cells are helping the community survive.”

The findings have implied that dense swarms, once exposed to low doses of antibiotics could actually lead to the acquisition of antibiotic resistance.

Meanwhile, UK Prime Minister Boris Johnson has declared vowed the country would get first access to Oxford University’s coronavirus vaccine if it works.

The vaccine is being developed by scientists from the university and pharmaceutical giant AstraZeneca.

Initial human trials suggest it is safe and creates an immune response to Covid-19.

However, it is not likely to be ready until next year.

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