Bacteria should poison themselves

US research approach: Bacteria are supposed to poison themselves

10.02.2011

US researchers have developed a new approach to fight dangerous bacteria with their own weapons. They want to reverse the mechanism that protects the pathogens from their self-produced poisons.

The bacteria would kill themselves as soon as the protective mechanism can be overridden, said the researchers of Washington University in St. Louis, USA in the current issue of the journal „Structure“. Most pathogens use a kind of antidote to protect themselves from the toxins they expel in the organism. If this antidote could be eliminated, the bacteria would die of their own toxins, according to the US researchers.

Protective mechanism of bacteria against their own toxins
As part of their research, researchers led by investigator Craig Smith have taken a closer look at the bacterium Streptococcus pyogenes and discovered how the pathogen protects against its own toxins. Streptococcus pyogenes is an unpleasant contemporary. The bacteria settle in the tissue of the pharynx and can cause both acute invasive infections and non-invasive sequelae. As the pathogen spreads, it distributes its toxins, which as tissue-dissolving enzymes damage or dissolve not only the red blood cells but also other cells , Scarlet fever, tonsillitis and pharyngitis are possible consequences of infection with Streptococcus pyogenes. To prevent the cells from being attacked by the tissue-dissolving poisons, the pathogen simultaneously produces an antidote, which attaches itself to the proteins of the bacterial toxin as a special protein molecule. The protection mechanism discovered by the US researchers provides a good approach for the future fight against bacteria. For if it were possible to develop an active ingredient that specifically eliminates the antidote, the pathogens would destroy themselves. The new method could not only be used in Streptococcus pyogenes, but also in many other bacteria that protect themselves in the same way from their own toxins.

Specialized protein molecule acts as an antidote
In investigating the Streptococcus pyogenes bacteria, the US researchers discovered a highly specialized protein responsible for protecting the pathogens from their own poisons. This protein molecule is able to take two different forms, and as soon as it hits the poison, it goes into a special structure to block the poison molecules, said Craig Smith and colleagues. The goal of future research should therefore be to find a way to keep the antidote in its inactive form, the researchers say. Because then the poison could not be blocked anymore and the bacteria would kill themselves. The scientists considered their discovery to be particularly important for the development of new antibacterial drugs, on the one hand „also many other bacteria (...) the same mechanism as Streptococcus pyogenes“ On the other hand, due to the increasing number of multidrug-resistant pathogens, drugs with new mechanisms of action to combat the bacteria are urgently needed.

Multi-drug resistant agents require new drugs
The spread of multidrug-resistant pathogens, which are immune to and resistant to almost all common antibiotics, has increased significantly in recent years. It is sometimes a serious problem, especially in hospitals and inpatient care facilities. Craig Smith claims that new medicines need to be continually developed to successfully combat antibiotic-resistant bacteria. The study director explained that there is war between the bacteria and the organism of the affected patients, in which the bacteria secrete poisons and the organism reacts via its immune system. In order to improve the chances of recovery, the infections are also usually combated with antibiotics, so Craig Smith on. „But as more and more pathogens develop resistance to antibiotics, we have to go new ways“, stressed the expert. Here, the findings now provide a good starting point in the opinion of the US scientist. (Fp)

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