Protecting gut bacteria: Targeted antibiotics reduce microbiome disruption in mice

Broad-spectrum antibiotics, commonly prescribed for many kinds of bacterial infections, are one of the great medical triumphs of our time. Before antibiotics, scientists had few tools to fight diseases that had affected humans for centuries; now, we can simply swallow an oral pill to fight off once-lethal infection within days. Penicillin alone is estimated to have saved up to 200 million lives since its discovery.

Still, taking antibiotics is not fun, and many people experience unpleasant side effects. In more serious cases, opportunistic secondary infections, such as C. difficult or C. albicans (yeast) can take root following antibiotic treatment. These side effects largely stem from the fact that antibiotics target and kill pathogenic bacteria as well as naturally-occurring bacteria. Today, as we begin to learn more about the importance of a healthy microbiome—bacteria that naturally occurs in our gut and elsewhere—researchers are now looking for a new, more selective kind of antibiotic.


Credit: mostly*harmless, flickr

This week, scientists from St Jude published a study that takes a small step towards selective antibiotics. Published in Antimicrobial Agents and Chemotherapythe researchers track how a targeted antibiotic—one that selectively inhibits a protein found in only a few bacterial species, including Staphylococcus aureus—altered the gut microbiome of mice in a 10-day treatment. Control mice received broad-spectrum antibiotics or an inactive agent.

At the end of ten days, mice that received the selective antibiotic had a gut microbiome that seemed largely unchanged. In contrast, the gut microbiota showed far reduced bacterial abundance and diversity in mice that received broad-spectrum antibiotics.

While these results are promising, it is important to note the limited sample size (only five mice were used per condition). Additionally, it remains to be seen how these results will translate to human subjects. Full text of this article can be found here.

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