New Antibiotic Blocks Toxins From Harmful Bacteria

U.S. researchers said on Thursday they have developed an antibiotic that works by blocking the communication signals of serious stomach bugs like salmonella, keeping them from releasing toxins that make people sick.

Dr. Vanessa Sperandio of the University of Texas Southwestern Medical Center said the sensors in bacteria are waiting for the right signal to initiate the expression of virulent genes.

Sperandio and colleagues found a compound named LED209, that disarms the bacteria instead killing it, like most antibiotics.

"Using LED209, we blocked those sensing mechanisms and basically tricked the bacteria to not recognize that they were within the host," said Sperandio.

Scientists say millions of potentially harmful bacteria are present in the body, but without the proper chemical signals, such as from a hormone, they simply pass through the digestive tract.

Researchers at UT Southwestern identified special receptors in prior studies on a diarrhea-causing strain of Escherichia coli that receive signals from microbes and hormones in the intestine that activate the bacteria.

But Sperandio’s team identified a chemical, LED209 that blocked sensors on bacterial cultures of E. coli, salmonella, and Francisella tularensis, which causes tularemia or “rabbit fever”.

The chemical was also found to keep mice infected with salmonella and F. tularensis from getting sick.

Sperandio said the study demonstrates that LED209 has promise in fighting at least three pathogens, and likely many more.

The researchers think it would not be easy for bacteria to develop antibiotic resistance because the new compound does not kill the bacteria, a problem common to most other antibiotics.