Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Comeback of an abandoned antibiotic: Trimethoprim is more effective than expected

19.03.2014

Scarlet fever and infections of the skin and throat are often caused by a bacterium called Streptococcus pyogenes.

In less-developed countries, inexpensive and well-tolerated antibiotics for therapy are often not available. Scientists of the Helmholtz Centre for Infection Research (HZI) in Braunschweig, Germany, have discovered that trimethoprim may provide an option.


Scientists use the zone of inhibition test to study antibiotic resistance of bacteria. The wafers contain an antibiotic that inhibits growth of sensitive bacteria in their vicinity. HZI/Bergmann und Nitsche-Schmitz

Contrary to a long-held belief, the bacteria are not generally resistant to this agent. In their recent publication, the scientists demonstrated that there are three potential pathways for the development of resistance - meaning that streptococci can easily become resistant to the antibiotic and pass on this trait quickly.

The common bacterium Streptococcus pyogenes is responsible not only for scarlet fever, a childhood disease presenting with characteristic skin rash, but also for many suppurative infections of the skin. The infection can be associated with serious consequences such as acute rheumatic fever and inflammation of the kidneys.

In Germany, physicians usually prescribe penicillin, an antibiotic. In less-developed countries, penicillin is not always an option though. Firstly, penicillin is often not available and secondly, co-infections, i.e. concurrent infections, by another bacterium called Staphylococcus aureus occur and this microorganism is often no longer susceptible to the action of penicillin.

A group of scientists directed by Dr Patric Nitsche-Schmitz of the HZI entered into cooperation with the German National Reference Center for Streptococci in Aachen, Germany, to investigate if the antibiotic trimethoprim can be helpful in these scenarios.

Trimethoprim inhibits an enzyme of folic acid metabolism called dihydrofolate reductase, which plays an important role in bacterial growth. Trimethoprim thus prevents bacteria from proliferating in the body. In the past, doctors advised against the use of this medication for treatment of streptococcal infections.

The underlying reasoning was the wide-spread belief that the bacteria are already resistant to this agent, a misconception, as is becoming increasingly more evident. The reason for this mistake is that early studies used a culture medium that reduces the anti-microbial effect of trimethoprim. 

The scientists from Braunschweig investigated samples from infected patients from Germany and India for resistance to trimethoprim. The majority of the samples were sensitive to the agent. "This shows that trimethoprim is indeed effective in many cases of Streptococcus pyogenes infection," Nitsche-Schmitz said. 

The focus of his team was also on samples, in which the bacteria failed to respond to the agent. They discovered two types of resistance. "Spontaneous mutations can occur in the gene for dihydrofolate reductase rendering trimethoprim no longer able to attack the changed enzyme, which means it becomes ineffective," Nitsche-Schmitz explained.

The team from Braunschweig detected a specific mutation in this gene in many samples, which renders streptococci resistant. In addition, bacteria can transfer copies of changed variants of the dihydrofolate reductase gene to other bacteria. This process called horizontal gene transfer allows resistance to spread very rapidly. The scientists found two genes of this type to be further causes of insensitivity.

The study shows that the antibiotic trimethoprim is a therapeutic option for Streptococcus pyogenes infections in some geographical regions of the world. The frequency of resistance is much lower than previously believed and the medication is inexpensive, stable and effective in Staphylococcus aureus co-infections.

"However, it is like a sword that can loose its sharpness quickly," Nitsche-Schmitz said. "We found three causes for the rapid spread of resistance. It is important that trimethoprim, like all antibiotics, is not prescribed without need and that patients take the agent in accordance with the instructions given."

Original publication:
René Bergmann, Mark van der Linden, Gursharan S. Chhatwal and D. Patric Nitsche-Schmitz
Factors that cause trimethoprim resistance in Streptococcus pyogenes
Antimicrobial Agent and Chemotherapy, 2014, doi: 10.1128/AAC.02282-13

The research group "Microbial interactions and processes" investigates the interplay of micro-organisms in complex communities made up of millions of cells and hundreds or even thousands of species. The group employs new methods for the identification of bacteria and the characterisation of bacterial activities in its work.

The Helmholtz Centre for Infection Research (HZI)
Scientists at the Helmholtz Centre for Infection Research in Braunschweig, Germany, are engaged in the study of different mechanisms of infection and of the body’s response to infection. Helping to improve the scientific community’s understanding of a given bacterium’s or virus’ pathogenicity is key to developing effective new treatments and vaccines.
http://www.helmholtz-hzi.de

Weitere Informationen:

http://www.helmholtz-hzi.de/en/news_events/news/view/article/complete/comeback_e... - This press release on www.helmholtz-hzi.de

Dr. Birgit Manno | Helmholtz-Zentrum

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>