|Methicillin-resistant Staph aureus. Photo NIAID|
The issue at stake here is, of course, the increasing prevalence of antibiotic-resistant bacteria worldwide, a situation well summarized in an article at Swissinfo.ch. We have thus seen a dramatic increase in resistant strains of, for instance, S. aureus, Escherichia coli and Klebsiella pneumoniae. Who or what is to blame? Most probably the overuse of antibiotics, not only in humans but also in animals. It is frightening to know that some pathogenic strains can survive our entire arsenal of antibiotics, while new potent drugs are extremely hard to find. Some simple solutions have helped mitigate the problem, notably more effective and systematic hand disinfection by hopital personnel, but this will not prevent all cases of infection. New antimicrobials are clearly needed, but where to find them?
Historically, soil bacteria have been our major source of antimicrobial compounds, particularly the genus Streptomyces. The discovery of new antibiotics from soil bacteria, however, has stalled in the past decades. One obvious reason is that we have already collected the low-hanging fruits: that is, compounds that are easy to isolate from bacteria that easily grow in the laboratory. The pool of remaining antimicrobial compounds in nature might be enormous, but the effort to mine it is substantial. This is what makes the paper by Ling and colleagues so interesting: it shows that we can extract useful drugs from soil microorganisms that are not readily cultivable in the laboratory.
|Structure of Teixobactin. Source Wikimedia commons.|
One downside is that teixobactin is only active against Gram-positive bacteria (Staphylococcus, Bacillus, Clostridium, Mycobacterium, etc.), whereas the most pressing problems are related to Gram-negative species. This notwithstanding, the discovery of teixobactin is a step in the right direction.
- Ling, L. L., et al. (2015) A new antibiotic kills pathogens without detectable resistance. Nature 517: pp.455-459.
- Nichols, D., et al. (2010) Use of iChip for high-throughput in situ cultivation of "uncultivable" microbial species. Applied Environmental Microbiology 76(8): pp. 2445-2450.