How relapses from illness happen: Researchers discover that some bacteria hide until the immune system calms, then attack again

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Image: How relapses from illness happen: Researchers discover that some bacteria hide until the immune system calms, then attack again

(Natural News) According to a study published in 2016, scientists have discovered a bacteria “alarm clock” that can wake dormant Salmonella in the body which enables the bug to trigger a relapse.

The researchers from Imperial College London say that the “alarm clock” is common among various types of bacteria, such as Salmonella and E. coli. Their discovery could explain why some people suffer repeated bouts of infections, like ear or urinary tract infections, even though they take antibiotics. The team aims to use these findings to look into “hard-to-treat infections.”

Dr. Sophie Helaine, the lead author of the research from the Department of Medicine at Imperial, said, “Whenever bacteria such as Salmonella invade the body, around a third of the bugs ‘cloak’ themselves as a defence mechanism against the body’s immune system. They enter a type of stand-by mode possibly to hide from the body’s immune system, that means they are not killed by antibiotics. The bacteria stop replicating and can remain in this dormant state for days, weeks or even months. When the immune system attack has passed, some bacterial cells spring back to life and trigger another infection.”

Dr. Helaine continued, “This is why, for instance, a woman may think she has recovered from a urinary tract infection – and yet days or weeks later it seems to return. Many patients may assume it’s a different infection – but actually it’s the same bug.” (Related: Boosting immune system with natural methods offers many health benefits.)


She adds that these so-called persistent bacteria also “fuel antibiotic resistance,” and this is why patients end up taking many courses of antibiotics for one infection. Taking this amount of antibiotics means that some bacteria are “developing resistance.”

Earlier research from Dr. Helaine’s lab determined that Salmonella bacteria go into stand-by mode by “poisoning” themselves using toxins.

In the current study, the team showed a mechanism that Salmonella use “to detoxify themselves.” This wakes them from stand-by and lets them start growing again.

Dr. Helaine said it is possible that many bacteria use this same toxin, called TacT, to “switch into stand-by mode.” These bacteria include those that cause many intestinal, ear, throat, or urinary tract infections and even tuberculosis.

Dr. Helaine shares that if they can determine how to control this particular mechanism and “force the bacteria out of stand-by” they can then be treated with antibiotics, effectively killing them.

For the study, Dr. Helaine et al. used Salmonella cells in the laboratory to identify the bacterial alarm clock. The team tested a collection of over 4,000 proteins to look for those that wake the bacteria up. They isolated an enzyme called peptidyl-tRNA hydrolase (Pth) that was an effective alarm clock.

The scientists have determined that the toxin TacT “stops cell growth during times of attack by blocking protein production.” When the conditions are more suitable for cell growth, Pth molecules eliminate the block on protein production and lets the growth continue.

Dr. Helaine concluded, “When the bacteria are under attack they go to sleep and wait for better days. Then once the immune system attack has passed, the body is once again a favourable place to start an infection, and cell growth resumes.”

Boost your immune system naturally

Don’t wait until you need antibiotics to get better. Try these natural tips to boost your immune system instead:

  • Get a good night’s rest and manage stress — Sleep deprivation and stress overload increase the hormone cortisol, prolonged elevation of which can suppress immune function.
  • Quit smoking or avoid second-hand tobacco smoke — Smoking undermines basic immune defenses and increase raises the risk of bronchitis and pneumonia in everyone and middle ear infections in children.
  • Eat healthier — Add plenty of vegetables, fruits, nuts, and seeds to your diet so your body has all the nutrients your immune system needs.

You can read more articles about preventing infections and illness at

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