NewYork-Presbyterian. The University Hospital of Columbia and Cornell.

-- New research revealed this week may lead to improved treatment and prevention of some bacterial infections.

Scientists at the University of Texas Southwestern Medical Center at Dallas have identified a receptor, QseC, that the Escherichia coli (or E. coli) bacterium uses to receive signals from hormones in the intestine and subsequently transmit the bacteria into the intestine to cause infection and symptoms such as diarrhea.

The UT Southwestern researchers are the first to identify the QseC receptor. Their research was published in the Proceedings of the National Academy of Sciences.

Substance Found to Block QseC Receptor

Once the infection-releasing receptor was identified, the researchers were then able to block the signals sent from the intestine using phentolamine, an alpha blocker medication commonly prescribed to control high blood pressure.

"This [QseC] receptor is found in many pathogens [infection-causing bacteria or viruses], so we can use this knowledge to design specific antagonists to block bacterial infections," says study author Dr. Vanessa Sperandio, assistant professor of microbiology at the university.

The researchers studied the effect of adrenergic antagonists - including alpha and beta blockers (adrenaline-blocking medications) - on the QseC receptor's capacity to receive signals from the hormones in the intestine.

Phentolamine was successful in adhering to the receptor and filling the space that it would normally fill with the epinephrine and norepinephrine, hormones which are secreted in response to stress.

Further Study Planned

This knowledge opens the door to further understanding of the signaling processes between microbes and humans and to the development of novel treatments of bacterial infections with antagonists to these signals, Dr. Sperandio says.

New therapies are important because treating some bacterial infections with conventional antibiotics can cause the release of more toxins, which can damage vital organs and worsen disease outcome.

That importance is magnified because QseC is also found in other types of bacteria, including Shigella, which causes dysentery; Salmonella, which causes food poisoning and gastroenteritis; and Yersinia, which causes bubonic plague.

These are all emerging infectious diseases that afflict thousands of people each year in the US and worldwide, according to the Centers for Disease Control and Prevention (CDC).

Prior research by Dr. Sperandio found that when a person ingests the more virulent enterohemorrhagic E coli, or EHEC - which is usually transmitted through contaminated food such as raw meat - it travels peacefully through the digestive tract until reaching the intestine.

There, however, chemicals produced by the friendly gastrointestinal bacteria and the human hormones epinephrine and norepinephrine alert the E. coli bacteria to its location.

This cellular cross talk triggers a cascade of genetic activations prompting EHEC to colonize and translocate toxins into cells, altering the makeup of the cells and robbing the body of nutrients.

An infected person may develop bloody diarrhea or even hemolytic uremic syndrome, which can cause death in immune-weakened people, the elderly and young children.

The findings from this new study may provide better insight into future treatments for bacterial infections without the use of antibiotics, the researchers say.

"Overuse of antibiotics has led bacteria to develop resistance to antibiotics, so a novel type of therapy is needed," Dr. Sperandio says.

Always consult your physician for more information.