Resistance against trimethoprim is not, apparently, as widespread as previously thought, therefore the antibiotic may at least partially make a comeback. It may be a therapeutic option to fight streptococci infections in less developed countries. This is the outcome of a German study presented in “Antimicrobial Agent and Chemotherapy”.
Streptococcus pyogenes causes, among others, scarlet fever as well as many types of skin inflammations, and an infection with this bacteria can lead to serious long-term consequences. In developed countries, the bacteria are usually treated with penicillin. But this is not always a suitable therapy, because co-infections with Staphylococcus aureus occur frequently, against which the antibiotic is often ineffective.
This is where trimethoprim may come in, believe scientists from the Helmholtz Centre for Infection Research (HZI) in Braunschweig and the National Reference Centre for Streptococci in Aachen. Until now, physicians advised against use of this medication for streptococci infections because it was believed that the bacteria were already resistant to this agent. However, according to the authors, this assumption is attributable to earlier studies in which a culture medium was used that weakened the anti-microbial effect of trimethoprim.
The researchers tested samples of infected patients from Germany and India for resistance to trimethoprim and did not detect insensitivity in the majority of the samples. “This shows that trimethoprim is indeed effective in many cases of streptococcus pyogenes infection”, said senior author Patric Nitsche-Schmitz. The extent of resistance was far lower than previously thought.