Turning bacteria off
The IPNA develops new antibiotics and substances that trick pathogenic bacteria to prevent them becoming virulent.
Antibiotic resistance is one of the greatest dangers facing society today. Without drastic remedial action, it is estimated that infections will become the leading cause of death in the world by 2050. One of the main causes of this problem has been the misuse of antibiotics. The more times a bacterium is exposed to an antibiotic, the greater the risk it will find a way to defend itself against the attack.
The Synthesis of Drugs research group at the Institute of Natural Products and Agrobiology (IPNA-CSIC) led by Alicia Boto, together with colleagues in the Agrobiotechnology group, is developing new antibiotics based on natural defence substances extracted from living species. These novel antibiotics, called antimicrobial peptides, attack bacteria in several ways at once. This combined attack is so effective that hardly any resistance against them has developed over millions of years. "Nevertheless, when a living thing is pushed to its limits, it is always possible for it to find a way to defend itself", Boto warns.
There is, however, a second strategy for fighting pathogens that the group is also studying. Like a social network, bacteria that take up residence in our bodies have the ability to communicate with each other at any time. This social characteristic becomes really useful when a pathogen is planning to launch a massive attack on its host. Through this communication regulated by natural chemicals, they can know their numbers, and when there are enough of them, they launch the attack. This communication also allows them to build a kind of 'bunker' called a biofilm, which allows them to live protected from antibiotics and their host's immune system.
The IPNA-CSIC group is looking for a way to break the root of this communication - called 'quorum sensing' - that allows them to organize themselves to defend themselves and to attack. "It's not about killing the bacteria, but about tricking them so that they don't become virulent or build their defensive biofilms," concludes Boto. "This deception is carried out by means of chemical substances that resemble their natural signals, but which transmit a different message, the one we are interested in," says the researcher. Because the bacteria are not killed or harmed in any way, this method significantly reduces the risk of resistance developing.
Researchers and clinicians around the world are also working together to try to reverse the damage caused by all these years of antibiotic misuse. "The first thing we can do is not to use antibiotics unless they are recommended by the doctor," explains Boto, who points out that "it is necessary to use these drugs responsibly, only when strictly necessary. If we take them, we should complete the prescribed course of doses". On the other hand, it is advisable to alternate the drugs used, always under medical advice. "If they have not been exposed to another antibiotic, the resistant bacteria no longer have any advantage over the others, and little by little they will revert to the sensitive strain".