Synthetic Antibiotics May Help Fight Drug-Resistant Bacteria

Scientists hope to harness the body's defenses against potentially deadly bacteria to create a new class of antibiotics.

Researchers at MIT and the University of Naples Federico II, Italy, found an enzyme used to digest food in the stomach called pepsinogen could destroy bacteria like salmonella and e.coli, both of which can kill if left untreated.

The research comes as scientists race against the clock to create new antibiotics as bacteria become resistant to existing medications. Last year, the World Health Organization reported that as many as 250,000 people a year worldwide died from multidrug resistant tuberculosis, and the world could soon run out of effective treatments to fight a number of dangerous illnesses. According to the Centers for Disease Control and Prevention, antibiotic resistance killed 23,000 people annually in the U.S. alone.

Scientists hope that peptides will help to solve this problem. Almost every living thing is armed with antimicrobial peptides, which can kill microbes but are not as powerful as antibiotic medications.

The team took a different approach and asked whether proteins other than the antimicrobial peptides could kill bacteria.To test their hypothesis, the researchers created an algorithm to analyze a database of almost 2,000 human protein sequences to find ones similar to antimicrobial peptides.

Cesar de la Fuente-Nunez, a postdoctoral associate at MIT and senior author of the paper published in the journal ACS Synthetic Biology, said in a statement: "It's a data-mining approach to very easily find peptides that were previously unexplored.

"We have patterns that we know are associated with classical antimicrobial peptides, and the search engine goes through the database and finds patterns that look similar to what we know makes up a peptide that kills bacteria."

The team found 800, which could potentially be used as a basis for creating a new class of antibiotics. The peptides tested on bacteria in lab dishes were found to kill microbes, including salmonella and e. coli, the authors of the study found.

Next, researchers dosed mice that had skin infections with three pepsinogen fragments and found they significantly reduced infections, although it was not clear why. The likely explanation, according to the researchers, was that peptides bind to and poke holes in bacterial membranes in a way similar to other antimicrobial peptides.

De la Fuente-Nunez said: "We have an atlas of all these molecules, and the next step is to demonstrate whether each of them actually has antimicrobial properties and whether each of them could be developed as a new antimicrobial."

De la Fuente-Nunez told Newsweek: "The key message is we are in the midst of a global health crisis where antibiotics no longer work. There have been a myriad of contributors to this current situation, one of which has been the massive overuse (and misuse) of antibiotics."

The use of antibiotics should be restricted to when strictly necessary, he argued.

"There is definitely hope. I think the key is to continue coming up with unconventional and disruptive approaches to generate antimicrobial therapies. And also try to look where no one has looked before."

This article has been updated with comment from Cesar de la Fuente Nunez.