Quick and sensitive identification of multidrug-resistant germs

December 07, 2020

Researchers from the University of Basel have developed a sensitive testing system that allows the rapid and reliable detection of resistance in bacteria. The system is based on tiny, functionalized cantilevers that bend due to binding of sample material. In the analyses, the system was able to detect resistance in a sample quantity equivalent to 1-10 bacteria.

Bacteria that are no longer susceptible to various antibiotics pose a significant threat to our health. In the event of a bacterial infection, physicians require rapid information about potential resistance so that they can respond quickly and correctly.

Cantilever systems as an alternative Traditional methods for detecting resistance are based on cultivating bacteria and testing their sensitivity to a spectrum of antibiotics. These methods take 48 to 72 hours to deliver results, and some strains of bacteria are difficult to cultivate. Molecular biological tests are a great deal faster and work by amplifying resistance genes or specific short sequences of genetic material by polymerase chain reaction (PCR), but even this method doesn't deliver satisfactory results for every bacterium.

An alternative comes in the form of methods using tiny cantilevers, which bend when RNA molecules bind to their surface, for example -- and this bending can then be detected. RNA molecules are "transcripts" of genes and can be used as instructions for building proteins. In addition, RNA molecules can be used to detect resistance genes in the genetic material of bacteria.

No need for labelling or amplification

Writing in the journal Global Challenges, a team of scientists from the Department of Physics, the Department of Biomedicine and the Swiss Nanoscience Institute (SNI) at the University of Basel have now presented a cantilever testing system that allowed them to detect RNA from a single antibiotic resistant bacterium. With the new cantilever system, it is not necessary to amplify or label the samples for analysis.

The researchers began by attaching sequences of three genes associated with vancomycin resistance to the cantilevers and then exposed these prepared cantilevers to a flow of RNA extracted from bacteria. If RNA molecules from the resistance genes were present, the matching RNA fragments would bind to the cantilevers, causing them to undergo nanoscale deflection that could be detected using a laser.

A clear signal even with point mutations This method allowed the detection of not only resistance genes, but also individual point mutations associated with them. To study this, the researchers used point mutations coupled to genes responsible for resistance to ampicillin and other betalactam antibiotics.

"The big advantage of the method we've developed is its speed and sensitivity," says Dr. François Huber, first author of the paper. "We succeeded in detecting tiny quantities of specific RNA fragments within five minutes." In the case of single mutations, the detected RNA quantities corresponded to about 10 bacteria. When it came to detecting entire resistance genes, the researchers obtained a clear signal even with an amount of RNA that corresponded to a single bacterium.

"If we can detect specific genes or mutations in the genome of bacteria, then we know what antibiotic resistance the bacteria will exhibit," explains Professor Adrian Egli from University Hospital Basel, whose team played an essential role in the study. "Our work in the hospital would benefit from this kind of reliable and sensitive information about the resistance of pathogens."
-end-


Swiss Nanoscience Institute, University of Basel

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.