The evolution of multiple antibiotic resistances is a global and difficult problem to eradicate.
Isabel Gordo, a group leader at the Instituto Gulbenkian de Ciência (IGC)- Portugal, reports in the paper published in the latest issue of PLoS Genetics (*), that the deleterious effect associated with the acquisition of resistance by a bacteria can be suppressed by the acquisition of a new resistance to another antibiotic. These findings have direct implications for the approaches taken to tackle the problem of multi-resistance to antibiotics and in the choice of antibiotics to be administrated to patients.
Acquisition of mutations is one of the ways by which bacteria become resistant to antibiotics. But this comes with a cost: although crucial for bacteria survival in a medium with antibiotics, in its absence bacteria growth rate is reduced. Although it is not possible to impaired bacteria to evolve and adapt to the environment, it is possible to choose the type of selective pressure (antibiotics) to administrate and, in this way, alter the course of evolution to our favour. This study shows the importance of knowing the costs of multi-resistance to find the best antibiotic combinations (the ones that carry more costs to the bacteria).
In collaboration with two other research groups at the IGC, Isabel's team selected populations of the bacteria, Escherichia coli, showing spontaneous mutations that confer resistance to common used antibiotics (the same used in the treatment of tuberculosis). This approach allowed the team to measure the effect of genetic interactions – a phenomenon scientists call epistasis- between the alleles of the genes involved in resistance. Epistasis is considered to be one of the key issues in Biology research.
Isabel describes their findings, 'To our surprise, when in a medium without antibiotics, bacteria that are carry resistance to two drugs have a higher survival rate than expected, showing a smaller cost to multiple resistance". Even more surprisingly, in some combinations (12%) the double mutants to two given antibiotics survive even better than if they were resistant to only one of the drugs. This is the worst scenario case for the host (including our species) and the best for the bacteria.
This study provides the first insight into the importance of genetic interaction between random alleles in determining antibiotic resistance in bacteria. From a public health point of view, it can also explains multi-drug resistance seen in bacteria associated with many diseases, such as tuberculosis (Mycobacterium tuberculosis), for which current treatments involve combinations of the same drugs used in this study.
According to Isabel: "This works shows how important it is to know the clinical history of the patient's antibiotic use as well as the specific bacteria's genotype associated with a given resistance in order to choose the appropriate treatment and obtain the best clinical outcomes". She adds: "From a more general point of view, this work uncovers the complexity associated with genomes ".(*)Trindade S, Sousa A, Xavier KB, Dionisio F, Ferreira MG, Gordo I(2009) Positive Epistasis Drives the Acquisition of Multidrug Resistance. PLoS Genet 5(7): e1000578. doi:10.1371/journal.pgen.1000578
(When published on July 24, the paper will be accessible at the following link: http://www.plosgenetics.org/doi/pgen.1000578)
Silvia Castro | EurekAlert!
Individual Receptors Caught at Work
19.10.2017 | Julius-Maximilians-Universität Würzburg
Rapid environmental change makes species more vulnerable to extinction
19.10.2017 | Universität Zürich
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
19.10.2017 | Materials Sciences
19.10.2017 | Materials Sciences
19.10.2017 | Physics and Astronomy