Crafty Bacteria Change Shape To Evade Antibiotics


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Antibiotics are becoming increasingly less effective as bacteria find ways to evade the drugs (Credit:

Antibiotics — medications that destroy or slow down bacteria growth — are becoming increasingly less effective as the pathogens find new ways to evade the drugs. Some produce pumps that flush the antibacterial medicines out from the bacterial cell, while others modify themselves, so they are unrecognizable as targets. Now, researchers at UK's Newcastle University have recorded the germs shedding their outer skins and changing their shapes to avoid detection.

Most bacteria are surrounded by a cell wall. The outer layer, which is akin to the human skin, protects the organisms against environmental stresses and prevents the cell from bursting. It also helps the human immune system flag the pathogen as a foreign entrant.

The researchers captured the L-form switching in E-coli bacteria on a Petri dish (Credit Newcastle University, UK)

“Imagine that the wall is like the bacteria wearing a high-vis jacket,” explains study lead author Dr. Katarzyna Mickiewicz. “This gives them a regular shape, for example, a rod or a sphere, making them strong and protecting them but also makes them highly visible – particularly to the human immune system and antibiotics like penicillin.” However, once the pathogens shed their walls, they become "invisible" and, therefore, hard to target.

The study, published in Nature Communications on September 26, 2019, focused on the various bacteria associated with recurrent urinary tract infections (UTI) in elderly patients. It found that many different bacterial species – including E. coli and Enterococcus – avoid the drugs by resorting to what researchers call "L-form switching." This clever technique, whereby a bacterium sheds its cell wall and takes on an L-shaped form, has been known since the 1930s. However, the pathogens' evasive nature has made it difficult for scientists to study it in detail.

The bacteria were able to re-build their walls once the antibiotics were removed (Credit: Newcastle University, UK)

The Newcastle University team successfully detected the sneaky bacteria in action by conducting the experiment in a Petri dish. The scientists observed that the pathogens rapidly began shedding their cell walls when exposed to antibiotics. Once the drugs were removed, the organisms were able to rebuild the protective layer within five hours. Using fluorescent probes, the team was also able to demonstrate the bacteria changing form in a transparent zebrafish embryo where bacteria were able to survive as L-forms once exposed to antibiotics.

Dr. Mickiewicz says: “In a healthy patient this [shedding the cell walls] would probably mean that the L-form bacteria left would be destroyed by their hosts’ immune system. But in a weakened or elderly patient, like in our samples, the L-form bacteria can survive. They can then re-form their cell walls, and the patient is yet again faced with another infection. And this may well be one of the main reasons why we see people with recurring UTIs."

The shape-shifting bacteria caught in action in zebrafish by using fluorescent probes (Credit: Newcastle University, UK)

The scientist believes the issue can easily be solved by treating patients with a combination of the usual antibiotics and drugs that kill L-forms. However, detecting the presence of L-shaped bacteria can often be a challenge. “Our battle with bacteria is ongoing. As we come up with new strategies to fight them, they come up with ways to fight back," Dr. Mickiewicz says. "Our study highlights yet another way that bacteria adapt that we’ll need to take into account in our continuing battle with infectious disease."

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  • master_expert
    master_expertover 3 years
    I did research and there is a bacteria-like creature That can kill germs. And also the resistant bugs are called Super bugs
  • asg318
    asg318over 3 years
    Wow!Who knew bacteria were so adaptable and could survive drugs!I loved the article!😄
    • roseslove
      rosesloveover 3 years
      This was very interesting! I did know that and I had a great time reading it!
      • waterfallgirl
        waterfallgirlover 3 years
        Hope they fix it soon
        • darbi
          darbiover 3 years
          The thing is we have a way to counter the antibiotics resistant bacteria but they don't think that it is safe. The counter is the Bacteriophage which is a virus that kills only bad bacteria.
          • fortnitemaster8
            fortnitemaster8about 3 years
            If it killed only bad bacteria, it would be a cure for cancer. Cancer is a virus that attaches itself to cells in your body and then proceeds to destroy the cells. Some cancers, such as skin cancer, can be treated if diagnosed early. This happens simply by the virus-infected skin being amputated, which removes the cancerous cells. Others, such as pancreatic cancer, cannot be treated. You can't just remove someone's pancreas and expect it to be okay. They just have to stay on life support and chemotherapy. With your miracle version of bacteriophage,(not capitalized) which found some time ago, we would be able to cure any cancer, and it would be just as treatable as a common cold. Bacteriophage doesn't just kill bad bacteria, it kills all bacteria. This would theoretically cure cancer, but also kill the person, which we don't want to do. As you can see, the bacteriophage is technically a cure, but not ideal, as it kills the host of the bacteria as well.
          • prettylovely
            prettylovelyover 3 years
            Wow that's cool i cant wait to tell my teacher and do it for my current event worksheet eek
            • lachie200
              lachie200over 3 years
              Hopefully we find a way to fix it?!?
              • lachie200
                lachie200over 3 years
                That's kinda really scary!!!
                • xpertthief62
                  xpertthief62over 3 years
                  I never even knew bacteria could do that!
                  • walttpa
                    walttpaover 3 years
                    This is so cool my teacher assined us to find one and I choose this one because who knew THIS very thing could happen!? 😃