Washington: Researchers from the University of Southern Denmark showed in 2008 that the drug thioridazine, which has previously been used to treat schizophrenia, is also a powerful weapon against antibiotic-resistant bacteria such as staphylococci ( Staphylococcus aureus ).
Antibiotic-resistant bacteria is a huge problem all over the world. For example, 25 - 50 percent of the inhabitants in southern Europe are resistant to staphylococci.
In the Scandinavian countries it is less than 5 percent, but also here the risk of resistance is on the rise.
So any effective anti-inflammatory candidate is important to investigate - even if the candidate is an antipsychotic that was originally developed to alleviate one of the hardest mental illnesses, schizophrenia.
Until now, scientists could only see that thioridazine works effectively and that it can kill staphylococcus bacteria in a flask in the laboratory, but now a new study reveals why and how thioridazine works.
The research team tested thioridazine on staphylococcal bacteria and discovered that thioridazine works by weakening the bacterial cell wall.
"When we treat the bacteria with antibiotics alone, nothing happens - the bacteria are not even affected. But when we add both thioridazine and antibiotics, something happens: thioridazine weakens the bacterial cell wall by removing glycine (an amino acid) from the cell wall. In the absence of glycine, the antibiotics can attack the weakened cell wall and kill staphylococcus bacteria", Janne Kudsk Klitgaard, visiting scholar at the Department of Biochemistry and Molecular Biology, University of Southern Denmark, said.
Thus, it is the interaction between thioridazine and antibiotic that works.
And now that researchers know that thioridazine works by weakening staphylococcal cell wall, they can concentrate on improving this ability.
The research is published in the journal PLOS ONE.