People use antibiotics far too often, with the result that pathogenic bacteria are becoming more and more resistant to these drugs. However, there is also another cause of increasing resistance, which has now been uncovered by Würzburg scientists who research infectious diseases.
Many infections that used to mean certain death can nowadays usually be overcome quickly by taking a few tablets. This is all thanks to antibiotics. So, it is all the more disturbing to physicians and patients alike that many pathogenic bacteria are becoming increasingly resistant to antibiotics.
From a colony of Staphylococcus aureus bacteria (middle, orange), groups that produce an antibiotic (white) and groups that are resistant to this antibiotic (periphery, yellow) gradually develop.
(Photo: Daniel Lopez)
This is particularly problematic in hospitals when bacteria spread that have become resistant to several antibiotics at the same time: these pathogens can be life-threatening for older and vulnerable patients. Sometimes such bacteria can be found in so-called biofilms on medical instruments or implants: they settle there in relatively large colonies inside a shared protective shell, which makes them even less receptive to drugs.
How is it that bacteria are becoming increasingly resistant? “It is because they come into contact with antibiotics too often and develop defense mechanisms,” according to the scientifically accepted explanation. Resistance is partly encouraged by the fact that physicians prescribe antibiotics too frequently and often even without good reason and by the fact that the agents are often mixed with food prophylactically in factory farming.
Competition between bacteria leads to resistance
Würzburg researchers have now discovered another way in which bacteria can become resistant – and surprisingly it has nothing to do with antibiotics used by humans. “Resistance already arises when competing bacteria live together in large numbers and in confined spaces,” says Dr. Daniel Lopez from the Research Center for Infectious Diseases at the University of Würzburg.
The scientists discovered this during experiments with Staphylococcus aureus bacteria, which are not resistant to antibiotics. They kept the bacteria under the conditions that prevail in a biofilm, i.e. numerous individuals in a confined space with a limited supply of nutrients.
A small evolution takes place in the biofilm
In this environment the Staphylococci become rivals and experience a kind of small-scale evolution: individual bacteria that are suddenly able to produce antibiotics through spontaneous mutations have the advantage. They keep the competition at a distance and multiply successfully. It is normal for bacteria to produce antibiotics themselves: even “in the wild” they use these agents to assert themselves against other bacteria, and many commonly prescribed antibiotics are derived from bacterial antibiotics.
In the biofilm created by the Würzburg researchers, the initial bacteria did not meekly surrender to this attack: they in turn developed mechanisms to defend themselves against the antibiotics, rendering themselves resistant. After just five days, there were three very distinctive groups of bacteria in the biofilm: the “harmless” original bacteria, the antibiotics producers, and the antibiotic-resistant group. This is reported by the Würzburg researchers in the current issue of the journal “Cell”.
Biofilms as breeding grounds for resistance
“Biofilms can therefore be breeding grounds for resistance without coming into contact with antibiotics from outside,” says Daniel Lopez. Consequently, hospitals should take even more care than they already do to prevent and combat biofilms. As their next step, the Würzburg researchers want to find out further details about what happens in biofilms. They are particularly interested in whether and how the ominous resistance development processes can be prevented.
“Evolution of Resistance to a Last-Resort Antibiotic in Staphylococcus aureus via Bacterial Competition”, Gudrun Koch, Ana Yepes, Konrad U. Förstner, Charlotte Wermser, Stephanie T. Stengel, Jennifer Modamio, Knut Ohlsen, Kevin R. Foster, and Daniel Lopez, Cell, Vol. 158, Issue 5, p1060–1071, 28. August 2014, DOI: 10.1016/j.cell.2014.06.046
Dr. Daniel Lopez, leader of the junior research group “Bacterial Cell Differentiation”, Research Center for Infectious Diseases, University of Würzburg, T +49 (0)931 31-83831, email@example.com
Daniel Lopez’s homepage: http://www.imib-wuerzburg.de/research/lopez/group-leader
Robert Emmerich | idw - Informationsdienst Wissenschaft
Zap! Graphene is bad news for bacteria
23.05.2017 | Rice University
Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine
23.05.2017 | University of California - Los Angeles
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Physics and Astronomy
23.05.2017 | Life Sciences
23.05.2017 | Medical Engineering