Scientists discover antibiotic-free way to treat drug-resistant infections: ScienceAlert
Scientists have found an antibiotic-free way to treat the ‘staph aureus’ skin infections that plague some cancer patients and a threat to hospitalized people everywhere.
The lab study by researchers at the University of Copenhagen used an artificial version of an enzyme produced naturally by bacteriophages (virus that infect bacteria), and used it to eradicate Staphylococcus aureus, or Staphylococcus aureus, in biopsy specimens from people with cutaneous lymphoma.
“For people with severe cutaneous lymphoma, staphylococci can be a huge, sometimes intractable problem, as many are infected with a type of Staphylococcus aureus which is resistant to antibiotics, explain immunologist Niels Ødum from the University of Copenhagen.
“That’s why we’re careful not to give everyone antibiotics, because we don’t want to deal with more resistant bacteria. It is therefore important that we find new ways to treat – and not least to prevent – these infections. “, explain Edema.
S. aureus IIt is a common inhabitant of our skin and nasal passages, and generally harmless. But it’s a opportunistic pathogen: When immunity is lowered, it can cause all kinds of infections, minor skin infections such as boils and abscesses, to life-threatening illnesses such as pneumonia and sepsis.
In the hospital setting, drug-resistant strains of bacteria are a serious and growing problem. S. aureus can enter the bloodstream during surgery or via medical devices such as catheters, slipping past the body’s first line of defense: the skin and mucous membrane barriers (snot).
People with weakened immune systems who visit hospitals for regular treatments such as chemotherapy are also at risk of contracting nasty “superbugs” that have become resistant to basic antibiotics.
In particular, people with cutaneous lymphoma are very susceptible to bacterial infections. Called cutaneous T-cell lymphoma, CTCL is a rare form of non-Hodgkin’s lymphoma that begins with cancerous T cells migrating to the skin. There, these rogue immune cells cause rashes and lesions before spreading to other parts of the body.
S. aureus expels substances called enterotoxins which are thought to fuel the progression of CTCL, because when patients with CTCL finish a course of antibiotics, S. aureus can quickly show up in skin lesions and their cancer symptoms can get worse.
strains of S. aureus resistant to methicillin and other antibiotics are called MRSA, and as hospitals progress curb MRSA infectionsother drug-resistant superbugs are quickly takes his place.
So in this study, Ødum and his colleagues experimented with the new class of antibacterial agents called endolysins.
Endolysins are enzymes produced naturally by bacteriophages, virus that infect bacteria. After infection, they cut through molecules called peptidoglycans that form mesh-like scaffolds in the cell wall of bacteria, destroying the bacteria from the inside.
Each bacterial species has unique peptidoglycans, which the right endolysin could selectively target. An endolysin, XZ.700, was tested in this study, on skin samples taken from people with healthy skin and from people with CTCL.
“The great thing about this enzyme is that it was designed to penetrate the wall of Staphylococcus aureus“, explain lead author and immunology researcher from the University of Copenhagen, Emil Pallesen.
“This allows it to target and kill harmful staphylococci and leave harmless skin bacteria unscathed.”
In laboratory experiments, endolysin XZ.700 killed strains of S. aureus which had been isolated from patients with CTCL and blocked its tumor-promoting effects on malignant T cells cultured in the laboratory.
Endolysin treatment also “deeply” stopped S. aureus from colonizing samples of healthy skin and biopsies of damaged skin from people with CTCL. He also got rid S. aureus colonies that had already settled on the biopsied skin.
“Our lab tests have shown that endolysins do more than just eradicate Staphylococcus aureus” from skin samples, said Ødum, but that they also “inhibit their ability to promote cancer growth”.
Although these laboratory experiments with skin biopsy specimens in plastic dishes fall far short of treating skin infections and cancer in real-life conditions, the results are promising.
Researchers hope that endolysin XZ.700 could kill drug-resistant strains such as MRSA and even biofilms, tightly-knit assemblies of microbes that are notoriously difficult to treat. Recent laboratory studies suggest that it might be possible, all without S. aureus develop resistance to endolysins.
This last point is essential, because bacteria are sneaky microbes capable of find new ways to evade and thwart antibiotic treatments faster than we can develop new drugs. More research is needed to really see if endolysins succumb to the same bacterial agility or stand firm against staph infections.
In 2019, antibiotic resistance recorded as third leading cause of death worldwide. The urgent need to find new treatments to fight drug-resistant bacteria is not just for cutaneous lymphoma patients, but a pressing global issue.
The study was published in the Journal of Investigative Dermatology.
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