Tuesday, January 20, 2015

New antibiotics: Prevention is important, too!

Klebsiella pneumoniaeLosee Ling et al recently described a new antibiotic compound, called teixobactin, that kills pathogens without detectable resistance. The abstract of their study notes that
. . . We developed several methods to grow uncultured organisms by cultivation in situ or by using specific growth factors. Here we report a new antibiotic that we term teixobactin, discovered in a screen of uncultured bacteria. Teixobactin inhibits cell wall synthesis by binding to a highly conserved motif of lipid II (precursor of peptidoglycan) and lipid III (precursor of cell wall teichoic acid). We did not obtain any mutants of Staphylococcus aureus or Mycobacterium tuberculosis resistant to teixobactin. The properties of this compound suggest a path towards developing antibiotics that are likely to avoid development of resistance.
It's a beautiful study, and obviously everybody hopes these implications are realized, and soon; new drugs are very badly needed. Eli Perencevich, writing in the blog Controversies in Hospital Infection Prevention, summarizes some of the important results from the study and also offers an important perspective,
I agree with Dr. William Schaffner's comments in the NY Times as he called the study/method “ingenious” yet also cautioned that "it’s at the test-tube and the mouse level, and mice are not men or women, and so moving beyond that is a large step, and many compounds have failed.” I would add one additional caveat  -- teixobactin had little activity against most Gram-negative bacteria including E. coli, Klebsiella and Pseudomonas. . . . Since the real resistance crisis is in multi drug-resistant Gram-negatives (think CRE, NDM-1), we better get back to digging in the dirt.
Certainly, these and other Gram negatives are important. As I've mused before, it's critically important to research infection prevention approaches in addition to investing in new drug development. We must understand how to prevent infections from occurring and spreading in healthcare (and other) settings before new drugs are introduced. It is clear that we do not possess this understanding, at least on any significant scale or in any sustainable way, at present.

(image source: CDC)

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