A typical treatment for bacterial imbalances is administering antibiotics to kill an overabundance of harmful bacteria. But as researchers in Belgium, Finland, and the Netherlands recently found, some diseases may require additional bacteria to treat.

In a study published in The Proceedings of the National Academy of Sciences, researchers from the Université Catholique de Louvain, the University of Helsinki, and Wageningen University show that raising the levels of human gut bacteria Akkermansia muciniphilia is one viable way to treat obesity and related metabolic disorders.

A. muciniphila, which lives in the mucus layer of the gut, degrades a family of proteins called mucins, the researchers write. Its presence is inversely related to weight in both humans and mice. Simply put, the more A. muciniphila bacteria, the less an organism weighs, and vice versa. In their study, the team showed that A. muciniphila levels are low in obese and diabetic mice. Furthermore, feeding probiotics that increase A. muciniphila levels back to normal correlated with an improved metabolic profile in the mice.

Additionally, treatment with A. muciniphila reversed mice's metabolic disorders, including fat-mass gain and insulin resistance induced by high-fat diets. Administering the bacteria also increased intestinal levels of endocannabinoids — a set of neuromodulatory lipids and their receptors — that control inflammation.

"This study provides substantial insight into the intricate mechanisms of bacterial (i.e., A. muciniphila) regulation of the cross-talk between the host and gut microbiota," the team wrote. "These results also provide a rationale for the development of a treatment that uses this human mucus colonizer for the prevention or treatment of obesity and its associated metabolic disorders."

Everard, A, Belzer, C, Geurts, L, Ouwerkerk, JP, Druart, C, Bindels, L, Guiot, Y, Derrien, M, Muccioli, GG, Delzenne, NM, de Vos, WM, Cani, PD. Cross-Talk Between Akkermansia Muciniphila and Intestinal Epithelium Controls Diet-Induced Obesity. PNAS. 2013. doi: 10.1073/pnas.1219451110. Accessed May 13, 2013.