At the root of two thirds of our antibiotics, anti-cancer agents and a good number of other molecules of pharmaceutical interest, the Streptomyces have made themselves indispensable to human beings. In a study published in EMBO reports (1), researchers at the universities of Leiden (Netherlands), Erlangen (Germany) and Liège have brought to light a ‘pivotal’ protein for the production of secondary metabolites in bacteria. A discovery which opens up new perspectives in terms of the battle against resistance to antibiotics and anti-cancer therapies.

If bacteria generally have a bad reputation and a simple allusion to them provokes disgust, certain of them are beneficial, or even indispensable, to human beings. The bacteria of intestinal flora, for example, allow the human body to disintegrate substances which the digestive system is incapable of breaking down.
Streptomyces also ‘serve’ humanity in their own particular manner. Belonging to the order of actinomycetales, these filamentous bacteria live in the soil, where they participate actively in the decomposition of organic matter. These micro-organisms feed themselves on the biomass residues of this subterranean environment and thus recycle decomposing vegetable matter there. They are to be found everywhere, but no need to panic: of the thousands of strains of this type of bacteria only one has ended up being pathogenic. For potatoes. Streptomyces are not only harmless to human beings, they have provided them with precious molecules since 1943 and the discovery of the streptomycin produced by Streptomyces griseus, used against tuberculosis.

Antibiotics to ensure their own survival 

These bacteria have in effect the ability to produce, in certain conditions, secondary metabolites which are of particularly interest to the pharmaceutical world. They are notably at the source of two thirds of our antibiotics and anti-tumour agents, as well as certain herbicides, antifungal substances and immunosuppressants. By way of example, Augmentin, an antibiotic prescribed in cases of otitis, sinusitis, bronchitis or cystitis, is produced from the basis of a mixture of amoxicillin and clavulancic acid. The latter is a ‘streptomycin molecule’ which inhibits beta-lactamases, enzymes which play an important role in the resistance to antibiotics found in some bacteria (read the article Antibiotics against Bacteria). 

(1) Rigali S, Titgemeyer F, Barends S, Mulder S, Thomae AW, Hopwood DA, van Wezel GP. Feast or Famine : the global regulator DasR links nutrient stress to antibiotic production by Streptomyces. EMBO Rep. 9, 7, 670-675 (2008).