Breaking the Barrier: Discovery of Antibiotic

Resistance Factors and Novel Ocean Drugs

Peter D. R. Moeller, Ph.D.Toxin/Natural Products Chemistry

National Ocean Service/NOAAHollings Marine Laboratory

Charleston, SC

Agelas coniferaDiseased coral reef – image taken from http://wwwimage.cbsnews.com/images/2002/06/17/image51

A Sponge happily survives A Sponge happily survives where everything else is dying.where everything else is dying.

How?How?

This Sponge provided us with a clue from

nature on how to deal with pathogenic microbes!

Survival Against Bacterial Infection

Dr. Ernesto Weil, University of Puerto Rico- Mayaquez, PR

• Marine organisms dwell in a microbial-rich environment

• Protect themselves against biofouling through the production of anti-biofilm natural compounds

• Utilize antibiotics to deter attack from infectious microbes

• These mechanisms can be used in a 1-2 punch approach to drug discovery

1st Punch: Production of Anti-Biofilm Chemicals

Bacteria often live as a community encased in a protective extracellular matrix (biofilm) attached to a biotic or abiotic surface.

• These biofilms protect bacteria effectively against coming into contact with antibiotics

• Removal of this protective biofilm-encasing may allow conventional antibiotics to work against multi-drug resistant bacteria

Biofilm Relevance To Human Health

Bacteria in biofilms are 1,000-fold more resistant to antibiotics

• 65-80% of all bacterial infections are biofilm-based

• Major cause of mortality in CF patients

• Cause infection of indwelling medical devices

• Nosocomial infections

• Destruction of citrus and other agricultural products

• Corrosion of petroleum pipelines

Agelas coniferaDiseased coral reef – image taken from http://wwwimage.cbsnews.com/images/2002/06/17/image51

Novel chemicals designed for Novel chemicals designed for biofilm inhibition/eliminationbiofilm inhibition/elimination

Chemical Defense Factory – Targeted, Selective, Efficient

HN

NH2N

NH2

NH2

HN

NH2N

NH2

NH2

Cis compound (CAGE) Trans compound (TAGE)

Biofilms of Pseudomonas aeruginosaOne of the causes of mortality in cystic fibrosis (CF) patients

Derivatives of Sponge-Derived Ageliferin Biofilm Disrupting Agents

Anti-biofilm Chemicals Enable Effective Use of Current Generation Antibiotics

A. baumanniiControl

Antibiotic Anti-biofilmagent

Antibiotic + Antibiofilm

agent

Acinetobacter baumannii

Isolated from military personnel wounded in Afghanistan

MRSA

Methicillin Resistant Staphylococcus aureus

MRSAControl

Methicillin Antibiotic

Anti-biofilm agent

Antibiotic + Antibiofilm

agent

Pseudomonas aeruginosa: Opportunistic pathogen infecting wounded soldiers, and indwelling medical devices. Significant source of mortality for cancer patients and CF patients.

Acinetobacter baumannii: Opportunistic pathogen infecting wounded soldiers and indwelling medical devices. Responsible for hospital closures and death of wounded war fighters. Multi-drug resistant strains to every known antibiotic have been isolated.

Vibrio vulnificus: Opportunistic pathogen that causes septicemia and seafood poisoning. It is related to the bacteria that causes Cholera.

Haemophilus influenzae: Opportunistic pathogen responsible for ear infections.

Bordetella: Pathogen that causes whooping cough. Responsible for 300,000 deaths/year.

Staphylococcus aureus and epidermidis: Bacterial pathogens that are the prevalently isolated from nosocomial infections. Has risen to prominence due to MRSA.

Halomonas pacifica: Biofouling of ships.

Efficacy Demonstrated Against Significant Infectious Bacteria

2nd Punch: Antibiotic Discovery A Focus on Pseudopterogorgia americana

A Caribbean Coral

Media Luna reef, La Parguera, Puerto Rico

The Caribbean has lost over 80% of its hard coral cover in the past years.

Visually healthy P. americana

Visually diseased P. americana (close-up)

Image Credit: Dr. Ernesto Weil, University of Puerto Rico- Mayaquez, PR

Chemical Warfare: Antimicrobial Screening Assay

Coral Isolate A vs K. rhizophila

Coral Isolate B vs P. aeruginosa

Coral Pathogens:

Vibrio coralliilyticus

Aspergillus sydowii

Human Pathogens:

Pseudomonas aeruginosa

Escherichia coli

Kocuria rhizophila

Bacillus spp. (B. subtilis)

Aspergillus spp. (A. sydowii)

Marine Invertebrate Pathogen:

V. harveyi

Inhibition

• Bacterial isolates tested against a series of pathogenic bacteria

• Antimicrobial screening often highlights potential antibiotic selectivity

• Selective antibiotic activity targets potential for “personalized medicine”

Isolating Novel Antibiotics from a Marine Bacterium

• Pseudovibrio denitrificans

• Recently discovered Genus specific to the marine environment

• Demonstrated strong broad spectrum antibiotic activity

• Produces several ‘suites’ of antibiotics, some with high selectivity.

Image Credit: Ben Neely, MUSC

1Sertan-de Guzman et al., 2007; 2Toledo et al., 2006; 3Hosoya and Yokota 2007

“Bring it on” species with attitude!

Loaded for Bear

Microbial Ecology: Microbe-microbe

interactions

Stressors and Response: Symbiont-pathogen

interaction

Chemical Ecology The study of chemicals involved in the

interactions of organisms within an ecosystem, with a focus on production and response to

natural products

Chemical Defense: Bioactive compound

production

Marine Natural Products Chemistry

Anti-cancer, Anti-fungal, Antibiotics, New Health Related Productions of Interest, New Agricultural Niche Crops

screening for viability

Acknowledgements

Christian Melander, Ph.D. Assistant Professor Department of Chemistry North Carolina State University

John Cavanagh, Ph.D. William Neal Reynolds Distinguished Professor Department of Molecular & Structural Biochemistry North Carolina State University

Anti-Biofilm Research Antibiotic Discovery

Pamela J. Morris, Ph.D.Associate ProfessorCell Biology and AnatomyMarine Biomedicine and Environmental Sciences CenterMedical University of South CarolinaHollings Marine Laboratory

Maria VizcainoPh.D. CandidateMarine Biomedicine and Environmental Sciences CenterMedical University of South CarolinaHollings Marine Laboratory

Funding Sources

NSF, NIH, SC SEAGRANT, NOS/NOAA