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ASM 2013, Day 1: From Oceans to Guts

Mimi Padmabandu
| May 20, 2013

oceanWith about 8,000 attendees and a diverse range of microbiology-related presentations, the American Society for Microbiology 2013 General Meeting (ASM) in Denver, CO tempts attendees with so much to see in so little time. This is my first year at ASM, and I was overwhelmed by the simultaneous depth and range of topics discussed, from clinical studies to citizen science to the relationship between oceans and human health.

This year at ASM, there was a strong indication that the correlation between the microbial populations of the ocean and human health is gaining prominence. Erin Lipp from the University of Georgia demonstrated the significance of Vibrio species (especially Vibrio cholerae, the causative agent of cholera) in the coastal ocean, noting that Vibrio-related illness rates are rising worldwide. Lipp also expanded on the role that climate change plays in disease dynamics—increases in temperature act as a driver for Vibrio replication and strain selection, resulting in significantly increased abundance of strains relevant to public health.

Agricultural runoff and sewage discharges are major pathogen reservoirs, and poor sanitation is a persistent problem even in developed countries. E. coli and enterococci are often used as indicators of fecal contamination, but since these species also persist in the environment, their use as indicators is limited. Sandra McLellan of the University of Wisconsin and colleagues used next-generation sequencing to identify alternative species besides E. coli and enterococci that indicate fecal pollution in sewage samples. They identified Lachnospiraceae and other species as alternative indicators, and network analysis of Lachnospiraceae identified specific phylotypes for humans. To perform this analysis, they examined specific oligotypes and found that these oligotypes provided sequence signatures that can act as indicators for specific organisms, resolving closely related sequences into host-specific phylotypes. They then tracked these species in the Great Lakes and found evidence of chronic sewage contamination in Lake Michigan.

Moving out of the ocean and into the human body, Ilana Cohen of the Fred Hutchinson Cancer Research Center infected mice with the human pathogen Heliobacter pylori—the causative agent of stomach ulcers and gastric cancer—by serial transmission, resulting in a mouse-adapted strain. She then performed multiplexed sequencing using Illumina technology and found 25 protein-altering single-base changes in the adapted H. pylori strains relative to the parental strains.

Discussing the clinical relevance of new technology in relation to pathogens, Richard Kellermayer presented an overview of how therapies for conditions such as inflammatory bowel disease have evolved over the last decade. While both antibiotics and probiotics have had varying success rates, complex and fecal bacteriotherapy has proven itself to be very promising. In a study that compared antibiotics against fecal microbiome transplantation to treat recurring C. dificile infection, fecal microbiome transplantation performed much better than treatment with vancomycin.

Finally, citizen science generated a considerable amount of buzz at this year’s ASM meeting. Darlene Cavalier’s talk explored how citizen science is transforming American research. Jessica Richman talked about uBiome, a citizen science startup that helps the public sequence their microbiomes. Antonio Gonzalez Peña discussed American Gut, the world’s largest open-source, community-driven effort to characterize microbial diversity in the global gut. The data from this effort will be uploaded onto the GitHub database for public evaluation.

Visit SciStarter to learn more about citizen science projects, and stay tuned for more updates from ASM 2013.