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

More articles from Life Sciences:

nachricht From rigid to flexible
29.08.2016 | Technische Universität Dresden

nachricht Moth takes advantage of defensive compounds in Physalis fruits
26.08.2016 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Streamlining accelerated computing for industry

PyFR code combines high accuracy with flexibility to resolve unsteady turbulence problems

Scientists and engineers striving to create the next machine-age marvel--whether it be a more aerodynamic rocket, a faster race car, or a higher-efficiency jet...

Im Focus: X-ray optics on a chip

Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.

In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of...

Im Focus: Piggyback battery for microchips: TU Graz researchers develop new battery concept

Electrochemists at TU Graz have managed to use monocrystalline semiconductor silicon as an active storage electrode in lithium batteries. This enables an integrated power supply to be made for microchips with a rechargeable battery.

Small electrical gadgets, such as mobile phones, tablets or notebooks, are indispensable accompaniments of everyday life. Integrated circuits in the interiors...

Im Focus: UCI physicists confirm possible discovery of fifth force of nature

Light particle could be key to understanding dark matter in universe

Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according...

Im Focus: Wi-fi from lasers

White light from lasers demonstrates data speeds of up to 2 GB/s

A nanocrystalline material that rapidly makes white light out of blue light has been developed by KAUST researchers.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

The energy transition is not possible without Geotechnics

25.08.2016 | Event News

New Ideas for the Shipping Industry

24.08.2016 | Event News

A week of excellence: 22 of the world’s best computer scientists and mathematicians in Heidelberg

12.08.2016 | Event News

 
Latest News

3-D-printed structures 'remember' their shapes

29.08.2016 | Materials Sciences

From rigid to flexible

29.08.2016 | Life Sciences

Sensor systems identify senior citizens at risk of falling within 3 weeks

29.08.2016 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>