Researchers from the of Bonn have found a strain of Staphylococcus aureus that defends itself against antibiotics in an unusual way. Details of the study appeared in the journal Microbiology Spectrum.
In the course of the study, scientists investigated the resistance of a strain of Staphylococcus aureus, which is harmless to humans. To do this, they grew a variant of bacteria in a laboratory in a nutrient medium and added vancomycin, an antibiotic of the glycopeptide group, there. The strain under study also lacks a mechanism that would normally repair genetic changes. This means it is rapidly gaining new properties, including those associated with increased antibiotic resistance.
“Within eight weeks, we received a strain that can cope with more than a hundredfold increase in antibiotic concentration,â€� explained Gabriele Bjerbaum of the Institute for Medical Microbiology, Immunology and Parasitology at the University Hospital Bonn. Researchers now want to figure out how other strains of staphylococcus can cope with the same task.
“Our bacterial strain has a much thicker wall than normal staphylococci. The cell wall also contains many molecular chains, the ends of which are hardly cross-linked. These uncrosslinked sites can bind vancomycin, â€�the researchers added.
The cell wall acts as a kind of sponge that absorbs the antibiotic and prevents it from reaching the membrane. At the same time, the bound vancomycin clogs the pores of this sponge and blocks the path to the membrane.