By Wendy Sarubbi | June 12, 2017 3:18 pm

Natural compounds extracted from sea sponges and other marine life may hold the secret weapon to fighting tuberculosis – a disease that is one of the top 10 causes of death worldwide.

An ongoing study led by Dr. Kyle Rohde, assistant professor at the Burnett School of Biomedical Sciences, has found that certain extracts from marine natural products, like sponges, may have the power to treat tuberculosis faster and better than existing drugs, particularly when bacteria have become dormant and drug-resistant.

His findings have been accepted for publication in Antimicrobial Agents and Chemotherapy, a journal published by the American Society of Microbiology. Dr. Rohde’s study is being funded by the National Institute of Health.

Tuberculosis, an infectious bacterial disease that mainly affects the lungs, is spread from person to person through the air.  Globally, there are about 10.5 million new cases and about 1.5 million deaths reported each year.

“One of the biggest problems is the lack of effective treatments,” Dr. Rohde explained.  “Tuberculosis is very difficult to treat and in most cases, takes six to nine months of taking at least four drugs daily. And most patients don’t stick to their drug regimens for six to nine months because they have undesirable side effects, or they stop taking it when they feel better.”

Tuberculosis bacteria have thick cell walls that drugs have difficulty penetrating. The bacteria also express proteins that make it resistant to treatment. And the bacteria can hide within the immune system and become dormant, only to reappear after treatment ends. “Most of the drugs we have only kill bacteria that are trying to replicate,” he said, “so we need drugs that can kill those dormant ones.”

Scientists have been isolating marine natural compounds from sea sponges and other marine organisms to find treatments for diseases such as cancer and tuberculosis. Dr. Rohde said many of these compounds are not in the sponges themselves, but are made from microorganisms such as fungi or bacteria that live on the sponges.

Through a partnership with Dr. Amy Wright of the Florida Atlantic University’s Harbor Branch Oceanographic Institute, Dr. Rohde and his team screened 4,400 chemical extracts derived from extracts of sponges and other marine organisms to see if they could fight the dormant tuberculosis bacteria.

“To our knowledge this is the largest marine natural product screening on TB and the only one that focused on dormant bacteria,” he said.

Of the 4400 samples tested, the team identified 26 compounds that were active against replicating tuberculosis bacteria, 19 killed dormant bacteria including seven that were active against both.

“There were some that actually killed the dormant bacteria better than the replicating bacteria, which is a novelty,” he said, “as existing drugs are better at killing replicating bacteria.”

The next step in the research will be to purify and further isolate the individual compounds in these extracts to identify which ones have antibacterial properties.

“Once we’ve identified these compounds, we want to study them to understand how they work,” Dr. Rohde said “That way if the compound turns out not to be a great drug for use in humans as is, at least we would have identified a new target for antibiotics. Alternatively, we could work with chemists to modify the drug to improve its clinical usefulness.”

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