In a variety of today’s headlines in the world of science and medicine, the ubiquitous bacteria warrant special mention. In our last blog posting, we described the alarming concern over antibiotic resistance. Today, current information provides us with on an overarching view of some ethics and social implications of the Human MicrobiomeProject, and then we drill down into the details of some recent microbiological discoveries that have been reported in the scientific literature.
On Friday, September 19, a regarded online publication named GenomeWeb Daily News reported that the National Institutes of Health plan to address the ethical, legaland social implications of the Human Microbiome Project (HMP). A brief definition of the project can be found here. In essence, HMP is proposed as a feasibility study with “the goal of identifying and characterizing the microorganisms which are found in association with both healthy and diseased humans” (from Wikipedia.org).
Social and ethical questions surround HMP which include questions about potential clinical applications of this research, the implications for health and for society, and privacy concerns for groups, individuals and families associated with the research. It’s important that these aspects are studied by the NIH and three awards of hundreds of thousands of dollars are available over the three-year timetable for this project.
Enter the lowly bacterium…
Several scientific headlines have been snatched by bacteria during the past couple of days. The first article of note also gives credit to the eukaryotic Candida albicans, where researchers from Beth Israel Deaconess Medical Center, Boston, and Harvard Medical School, Boston describe prokaryotic-eukaryotic interactions of Acinetobacter baumannii and C. albicans as identified using the common nematode Caenorhabditis elegans. A paucity of data exists on the bacterial-fungal encounters within a living host and in this study, A. baumannii inhibited virulence of C. albicans. This in vivo work supports existing in vitro studies. The study provides a whole-animal model to open the door to investigating the dynamics of polymicrobial infections.
Another study reported in the October issue of the Journal of Medical Microbiology received recognition today when several articles described the interactions of the gut bacterium Enterococcus faecalis and colon cells (Medical News Today, September 22, 2008, “Gut Bacterium Linked to Colon Cancer”, www.medicalnewstoday.com, ScienceDaily, September 22, 2008, “Cancer-causing Gut Bacteria Exposed”, www.sciencedaily.com/releases/2008/09/08092120171.htm, Allen, T.D., et al., 2008. Dichotomous metabolsim of Enterococcus faecalis induced by haematin starvation modulates colonic gene expression. J Med Microbiol 57:1193-1204.) This bacterium can survive using respiration or fermantation, and when it relies on the latter metabolic processes it releases superoxide, which leads to signalling in macrophages. Superoxide also increades the productivity of genes that are associated with cancer.
In another host/bacterium study, investigators at the University of Chicago and Yale University demonstrated that when mice were exposed to some forms of bacteria the onset of Type I diabetes may be prevented by upsetting this autoimmune disease. In a paper published in Nature, Li Wen at Yale and Alexander V. Chervonsky at the University of Chicago demonstrated that non-obese diabetic (NOD) mice were significantly less likely to develop diabetes when exposed to harmless gut bacteria. Understanding the balance of the bacterial / disease interaction is important for understanding the underlying basis for the disease.
Initiatives to better understand the Human Microbiome and studies that publish data to help understand disease / bacterial interactions move us closer to understanding our links with the microbiological world. The use of probiotics has been suggested in the popular press for establishing healthy microflora. Now, we may be more dependent upon our microflora for good health than we ever thought imagineable in the past.