UK scientists id shape-shifting bacteria behind antibiotic resistance

October 2, 2019

The World Health Organisation (WHO) has identified antibiotic resistance as one of the biggest, fatal threats affecting people in many regions around the globe. Antibiotics typically target bacterial cell walls as part of its healing mechanism, but scientists from Newcastle University in UK have, for the first time, seen that bacteria can change form to avoid being detected by antibiotics in the human body.

The novel research by the university’s Errington lab used samples from elderly patients with recurring urinary tract infections (UTIs)who were administered penicillin or other cell wall-targeting antibiotics.

In a sly movement known as “L-form switching” the bacteria has the ability to change form and lose its cell wall – the L-form makes the bacteria flimsy and weak, but ensures it will survive the antibiotic assault.The L-form bacteria isolated from a patient with UTI also re-formed its cell wall within 5 hours after the antibiotic was out of the system.

The scientists showed that L-forms of various bacterial species typically associated with UTIs, including E. coli, were detectable in 29 out of 30 patients. The scientists were also able to show, via direct microscopy in a transparent zebrafish model, that the L-form switching was possible in a whole living organism and not only in artificial specimens –

Newcastle University’s Dr. Katarzyna Mickiewicz explains that the cell wall is like a yellow jacket. It lends the bacteria a regular shape and protects them, but also makes them highly visible to the human immune system and antibiotics.

“What we have seen is that in the presence of antibiotics, the bacteria are able to change from a highly regular walled form to a completely random, cell wall-deficient L-form state- in effect, shedding the yellow jacket and hiding it inside themselves, so neither the body nor the antibiotics can recognise the bacteria.”

Dr. Mickiewicz adds, “A healthy patients’ immune system would probably destroy the L-form bacteria left behind. But in weakened or elderly patients, the L-form bacteria can easily survive. This may well be one of the reasons why we see recurring UTIs.

Therefore, clinicians should consider treating antibiotic-resistant bacteria with treatments that target the bacterial DNA/RNA or even the surrounding membrane, for more effective results.


Category: Pharmaceuticals

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