Deep-sea sponges could be answer to finding new antibiotics

FORT LAUDERDALE, Fla. – The solution to a vexing — and deadly — problem for modern medicine could be lying on the ocean floor.

Just like some insects have evolved to resist synthetic chemical insecticides, new infectious diseases have emerged over the past 20 years that can't be controlled by the antibiotics doctors have at their disposal.

It could be sea sponges to the rescue, scientists said.

In a study published in the journal Frontiers in Microbiology, researchers identified several chemical compounds produced by microbes that live in deep-sea sponges.

These secretions show promise in defeating antibiotic-resistant infections such as Methicillin-resistant Staphylococcus aureus (MRSA) and clostridium difficile (C.diff), which menace patients in hospitals and long-term nursing facilities and cause numerous deaths every year.

"There is this desperate need to find new antibiotics," said Peter McCarthy, a marine microbiology professor at Harbor Branch Oceanographic Institute. "We have picked up many sponges that have never been seen before. So that led us to believe they contained microbes that had never been seen before."

The Centers for Disease Control and Prevention puts C.diff at the most urgent level of threat. MRSA is categorized as a "serious" threat.

The lab at Harbor Branch has sponge samples collected over the past 30 years from as deep as 3,000 feet under the sea off the coasts of the United States, the Caribbean, Europe and Africa. Studying these sponges, scientists have identified about 19,000 microorganisms that live in these sponges.

As part of the sponges' natural defense against other organisms invading their space, these microbes produce compounds that keep the invaders away and sponges thriving undersea.

They've been testing how chemicals in the microbes that keep the sponges healthy react against the antibiotic-resistant diseases that threaten humankind.

"There is so much diversity and so much competition down there. These microbes are creating the anti-bacterial compounds, " said McCarthy, who is working with researchers at the University of South Florida, the University of Kentucky and the Central South University in Changsha, China.

Triggering the microbes to secrete these compounds in the lab, scientists have found the secretions are effective against deadly bacterial pathogens when they go head to head in a petri dish.

Researchers were able to identify a chemical defense from the sponges that appeared more potent than the medicine, vancomycin, given intravenously to combat the C.diff. infection.

With funding from the Harbor Branch Oceanographic Institute Foundation and the National Institutes of Health, researchers are identifying how these microbes produce the antibacterial compounds so that humankind can do the same.

'We don't fully understand why they are making chemicals," McCarthy said. "We do not yet understand the ecology of it."