Sea sponge survival key to possible cures: 4/10

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Sea sponge survival key to possible cures

by Mary Helen Yarborough
Public Relations
In pursuit of antibiotic resistant bacterial infections, MUSC scientists, their collaborators at North Carolina State University (NCSU), and the Hollings Marine Laboratory (HML) have found astonishing disease-fighting potential by investigating the resilient sea sponge.

Their findings through joint research between MUSC, NCSU and the National Oceanic and Atmospheric Administration (NOAA), could open new therapies for treating antibiotic resistant infections, cancer, and fungal infections.

The discovery of how some bacteria protect themselves in the presence of a compound they produce called “biofilm” has spotlighted a novel weakness in the bacteria’s survival mechanism.

Scientists looked at how a sea sponge was thriving amid an otherwise bleak environment surrounded by dying coral. They identified a compound that the sponge produces that removes bacterial biofilms and inhibits biofilm production that resistant bacteria use to protect themselves from physical and chemical insults, such as antibiotics. Removing a bacteria’s biofilm’s naturally-protective properties can result in a “re-sensitization” to antibiotic activity.

Between 65 percent and 80 percent of bacterial infections are biofilm-based, according to Pete Moeller, Ph.D., an HML-based NOAA scientist involved in the multi-institutional study.

Researchers have known for some time that the biofilms produced by resistant bacteria provide effective protection against antibiotics. By removing the biofilm, these compounds provide an open door for a stealth attack on the bacteria.

These resistant bacteria include Pseudomonas auriginosa, the causative agent of mortality in cystic fibrosis patients; methicillin resistant staphylococcus aureus (MRSA); and the killer bacteria—multi-drug resistant Acinetobacter baumannii (MDRAB), said Moeller.

A number of MDRAB are reported to be resistant to all known currently-used antibiotics, Moeller said. “It is one of the most deadly bacteria known. But (NCSU) colleagues killed it in two-to-four hours by removing its biofilm mechanism so antibiotics could perform. NCSU colleagues leading this program have yet to find a biofilm-producing bacterium that cannot be re-sensitized to current generation antibiotics.”

In addition to developing these new chemical tools and using them to fight the antibiotic resistance war, Moeller said, “... We can also isolate new medicines from the marine environment that can be customized to individuals’ needs rather than relying on broad spectrum antibiotics, or non-specific anti-cancer agents.

“This could lead to a new class of helper drugs and result in a rebirth for antibiotics no longer thought effective,” Moeller told an assembly of the American Association for the Advancement of Science. “Its potential application to prevent biofilm build-up in stents, intravenous lines and other medical uses is incredible.”

The compound is currently being tested for a variety of medical uses and has gone through a second round of sophisticated toxicity screening and so far shows no toxic effects. Now, if only more funding was available for the research and trials, Moeller added.

Looking for novel germs
Maria Vizcaino, an MUSC doctoral student at HML, had been searching for novel marine antibiotics to treat antibiotic resistant bacteria, and believed that clues exist in the oceanic frontier being opened by Moeller’s research.

For her work, Maria Vizcaino was awarded a 2009 American Society for Microbiology Cooperative Activities Program Student Travel Grant to attend the 109th General Meeting in Philadelphia, Pa.

In 2006, Vizcaino’s co-mentor, Pam Morris, Ph.D., of MUSC’s Marine Biomedicine and Environmental Sciences Center, obtained a National Science Foundation grant to characterize microoganisms associated with Caribbean corals. This project provided Vizcaino and her mentors, Morris and Moeller, the marine bacteria to screen for novel activities.

“Maria started screening bacteria associated with a Caribbean coral for their potential in producing antimicrobial compounds,” Morris said. “And she began to look more closely at the pathogen (Vibrio coralliilyticus) that is a coral pathogen.”

Vizcaino isolated a relatively unstudied bacterium from the Pseudovibrio genus that is associated with a lot of the marine invertebrates that is helping saltwater fish grow healthier and stronger through enhanced immunity, said NOAA’s Susan Lovelace, Ph.D., a scientist with an HML lab and project.

Vizcaino has started to isolate and characterize the antibiotic compounds that she anticipates are novel. Her findings could lead to cures to the world’s most daunting diseases, including cancer, antibiotic-resistance and viruses.

For her work (Characterization of Marine Antimicrobial Compounds from a Pseudovibrio sp. Associated with the Surface Mucopolysaccharide Layer of a Caribbean Coral), Vizcaino has been awarded a 2009 American Society for Microbiology (ASM) Cooperative Activities Program Student Travel Grant to attend the ASM’s 109th General Meeting in Pennsylvania, May 17-21. (See http://www.musc.edu/mbes)

Friday, April 10, 2009

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