Antibiotic resistance is a clear and present danger for humanity. Several microorganisms have developed ways to become immune to antibiotics leaving us without tools to fight them off. Bacteria, in particular, can quickly develop resistance by changes in their genome. But this might not be the only way.
As reported in Nature Communication, researchers have found evidence that bacteria can survive antibiotic attacks by changing shape and shedding their cell walls, their outermost defense and the primary target of most antibiotics like penicillin.
Usually, this approach is effective in killing bacteria, but in certain conditions, the bacteria can survive. The bacteria without cell walls only have a cell membrane (just like animal cells) and are known as L-forms, discovered by Emmy Klieneberger-Nobel in 1935. Without the rigid cell wall, these bacteria can change shape.
Obviously without the cell wall, they become more fragile, but this might be a blessing in disguise for some of them. Without the cell wall, they are no longer recognizable and so they might also become undetectable by the immune system. For these reasons, researchers thought that L-forms could be a potential avenue for bacteria to survive in the human body.
“This is something that has never been directly proven before. We were able to detect these sneaky bacteria using fluorescent probes that recognize bacterial DNA,” the lead author Dr Katarzyna Mickiewicz, from Newcastle University, wrote in a blog post published in The Conversation.
“We tested urine samples from elderly patients with recurrent UTIs by growing them in a petri dish high in sugars. Not only did this environment help protect bacteria from bursting, but it also isolated the L-form bacteria that were present in these samples.”
The team also witnessed the same process inside zebrafish embryos, where bacteria were able to survive as L-forms once exposed to antibiotics. Given the brand-new nature of the study, the researchers are still not sure how crucial this form of resistance is compared to the rest. But it highlights the importance of testing antibiotics in settings that truly resemble the human body.
“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 continued. "Our study highlights yet another way that bacteria adapt that we’ll need to take into account in our continuing battle with infectious disease.”
It is estimated that 700,000 people die every year due to antibiotic resistance. The number is expected to rise to 10 million in 2050 according to the World Health Organization. And bacteria is not the only microorganism that is developing resistance, fungi are too.
[H/T: The Conversation]