Express diagnostics of bacterial sensitivity to antibiotics
Nanocambertons were used to search for dangerous bacteria
<url>Swiss researchers have proposed a new way to identify antibiotic-resistant bacteria.
Their method is based on the use of nanocambertons, which begin to oscillate when bacteria actively absorbing the substrate are placed on them. The invention is described in detail in the journal Nature Nanotechnology (Longo et al., Rapid detection of bacterial resistance to antibiotics using AFM cantilevers as nanomechanical sensors), and Science news briefly tells about it (Microscopic 'Tuning Forks' Could Make the Difference Between Life and Death in the Hospital).
As a nanocamber, scientists used standard cantilevers – microscopic brackets usually used to hold the needle of an atomic force microscope. Scientists placed a thin layer of nutrient substrate and bacteria on the cantilever, which, as part of the experiment, imitated pathogenic microorganisms to be determined.
The sensitivity of the cantilever turned out to be so high that even bacterial cells absorbing the substrate were able to influence its vibrations.
Diagram from an article in Nature Nanotechnology According to the researchers, their development confidently distinguishes living cells from dead ones precisely due to the movement of the cantilever, and this compares favorably with the PCR method, polymerase chain reaction, recognized as the standard of diagnostics.
PCR allows you to very accurately determine the type of bacteria by characteristic DNA fragments, but the presence of DNA in itself does not mean anything that the analyzed sample contained live, not killed bacteria.
If the cantilever is treated with an antibiotic solution that is effective against bacteria of this strain, then the fluctuations subside; parallel exposure to several cantilevers allows you to pick up an effective medicine in just minutes.
The authors of the development emphasize that such speed is crucial in clinical settings: a patient with severe sepsis without treatment can die in just a few hours, while the traditional method of determining antibiotic resistance requires several days of painstaking work. As part of a routine diagnosis, microbiologists first isolate bacteria, then transplant them to a nutrient medium and grow colonies, which are then treated with various drugs.
Portal "Eternal youth" http://vechnayamolodost.ru02.07.2013