Bacteria "starve" like humans and release harmful toxins that make us sick

A study finds that some bacteria cells can become "hungry" and irritable, just like humans.

Microbiologists have found that a lack of nutrients causes some bacterial cells to release harmful toxins into our bodies that can make us sick.

While the current study focused on just one bacterium, if the results are identical to other species, this could pave the way for new treatments for infections, according to the study published in Nature Microbiology.

The study was conducted by microbiologist Professor Adam Rosenthal of the University of North Carolina at Chapel Hill and colleagues from Harvard and Princeton Universities, as well as Dutch pet food company Danisco.

Professor Rosenthal said: "Bacteria behave much differently than we have traditionally thought. Even when we study a community of genetically similar bacteria, they don't all behave in the same way. And we wanted to find out why."

The team used a newly developed analysis method called "probe-based bacterial sequencing" to read RNA molecules from thousands of individual bacteria.

The latter bacterial species are commonly found in nature and are a major cause of food poisoning.

The researchers suggested that genetically similar cells within the bacterial community have different functions, with some organs behaving more obediently while others produce toxins that make us feel sick.

Rosenthal decided to take a closer look at why some cells act as "well-behaved residents" and others as "bad actors" tasked with releasing toxins into the environment around them.

The team selected Clostridium perfringens (or C. perfringens), a bacterium that can be found in the intestines of humans, vertebrates, insects and soil, for the study. They were able to separate or divide single bacterial cells into droplets to decode each cell individually.

They identified a bacterial subpopulation that produces and releases a toxin known as "netB". However, this is only possible in the absence of acetate, a short-chain fatty acid that is widely distributed in the gut.

They found that C. perfringens cells that did not produce toxins were well fed with the nutrients. On the other hand, C. perfringens toxin-producing cells appear to lack these essential nutrients.

Based on the finding that nutrients play an important role in bacterial toxicity, Professor Rosenthal said he now wonders whether there are specific factors present in the environment that 'turn on' the production of toxins in bacterial pathogens other than C. perfringens.

If so, introducing nutrients to bacteria could provide a new way to treat bacterial infections in both humans and animals.

In fact, C. perfringens is known to infect chickens, being highly contagious and fatal to birds, and as the poultry industry moves away from the use of antibiotics, new defenses against the disease are needed.

Accordingly, the new study suggests a potential new way for farmers to reduce disease-causing bacteria among their flocks without resorting to antibiotics.

As for us humans, there is more work to be done.

Rosenthal and colleagues seek to apply their recent findings to address antibiotic tolerance. Antibiotic tolerance occurs when some bacteria are able to evade a drug target even when the population has not developed mutations to make all cells resistant to an antibiotic. This tolerance can lead to less effective treatment, but the mechanisms that control tolerance are not well understood.

With their initial study complete, the researchers are now continuing to study the behavior of these complex bacterial communities.

The full results of the study have been published in the journal Nature Microbiology.