Two recent studies that shed light on the inner workings of our bacterial ecosystems, otherwise known as our microbiota, have me musing on the nature of disease and pathology, of harmony and balance.
The first study caused a stir in the media with its admittedly unorthodox solution to a brutal bacterial infection; I'm speaking of the infamous "fecal transplant" study conducted in the Netherlands that was used to treat chronic, untreatable C. difficile infections. Commonly referred to as "C. diff," this infection is notoriously difficult to cure, not to mention a dreadful and painful nuisance in those afflicted. Many researchers know that the infection can be attributed to a bacterial imbalance in the gut, a "persistent disturbance with a reduced diversity of intestinal microbiota (1)." When a population of C. diff bacteria edge out existing gut flora beneficial to your intestinal ssytem, they establish a dominant presence that's marked by severe abdominal pain, appetite loss and watery diarrhea that can lead an unfortunate individual to use the restroom up to 15 times each day. The ominously named fecal transplant in question is a radical method of restoring balance to the gut, infusing processed feces laden with good bacteria from a donor into the gut of a person afflicted with C. diff. The goal, and a successful one at that, is to replace C. diff with a more amenable population of fecal bacteria.
The second study that's been on my mind concerns those wicked bacteria on your face that cause the dreaded "z word" - zits! Though you may not know it, your face is host to several strains of the skin-dwelling bacteria Propionibacterium acnes. Researchers at the University of California, Los Angeles and Washington University have found that people who suffer from acne have a greater preponderance of two particular strains of P. acnes, R4 and R5, than clear-skinned folk, who have a greater proportion of strain R6. Their study suggests that blemishes and pimples may be a result of an asymmetry or population imbalance between the good and malevolent strains of P. acnes. The force is within us and it is a battle for clear smooth skin.
A few of the microorganisms that comprise the body's microbiota. There is an interactive version at Scientific American that you can play with here. Image: Bryan Christie for Scientific American. Click for source.
Yes, I know the subject is gross - poop and pimples, great! - but these recent studies reinforce a compelling idea about our microbiota that has been brewing for a few years: that some infectious diseases may be due in part to a disharmonious balance between pathogenic bad-guy bacteria and our resident commensal good-guy bacteria. The day-to-day working of our bodies - our gurgling gut, the relentless give-and-take of our lungs and even the zinging neurotransmitters in our brains - relies on equilibrium and balance in our ecosystems.
This may sound a little wishy-washy, maybe even a little New Age-y, but we've seen this phenomenon before on a macro-scale. We've seen it with the invasion of cane toads and rabbits in Australia and the ensuing devastation of the country's ecology. Most of us see it everyday around 7 am and 5 pm on our highways. Heart attacks and arterial congestion, runaway climate change, and the United States subprime mortgage crisis and housing bubble.
At a time when we are plowing through our available stockpile of antibiotics to treat bacterial infections, giving some consideration to the exciting ideas unearthed by these studies might change the very way that we treat and think of microbial diseases. What other human diseases could be attributed to asymmetrical microbial warfare, to a disruption in the harmony of our microbial communities? What ailments could we treat by adding healthy bacteria to a bad situation? Wounds seething away with MRSA? Urinary tract infections in women? What of obesity and anxiety? The possibilities may not endless, but they may very well be within us.
"The infusion of donor feces is a potential therapeutic strategy against recurrent C. difficile infection (01)." Find out more about the "fecal transplant" procedure used to treat recurrent C. diff infections here.
For more on the battle between good and bad P. acnes strains, check out this write-up of the acne study here at Wired.
"Microbes defy a simple notion of individuality. They are essential to our biology, and they travel with us from birth to death. Yet they also flow between us, and can be found in water, food and soil." A lovely article by Carl Zimmer, "Our Microbiomes, Ourselves" at the NYT.
Discover the organisms that comprise the body's microbiota in this neat interaction here.
(2) S Fitz-Gibbon et al. (2013) Propionibacterium acnes Strain Populations in the Human Skin Microbiome Associated with Acne. J Invest Dermatol. Epub ahead of print.
van Nood, E., Vrieze, A., Nieuwdorp, M., Fuentes, S., Zoetendal, E., de Vos, W., Visser, C., Kuijper, E., Bartelsman, J., Tijssen, J., Speelman, P., Dijkgraaf, M., & Keller, J. (2013). Duodenal Infusion of Donor Feces for Recurrent Clostridium difficile. New England Journal of Medicine, 368 (5), 407-415 DOI: 10.1056/NEJMoa1205037