Enzyme to protect 'good' gut bacteria from antibiotics

You may soon take antibiotics without fearing the loss of "good bacteria" residing in the intestines.

Researchers from Case Western Reserve University in Cleveland have discovered that populating the gastrointestinal (GI) tracts of mice with Bacteroides species producing a specific enzyme helps protect the "good" bacteria from the harmful effects of antibiotics.

"The results are exciting as it might be possible to take antibiotics without suffering from the loss of your colonic microbiome and then becoming colonised by virulent pathogens," said lead researcher Usha Stiefel Case Western Reserve University.

The novel aspect of the research is that the enzyme produced by these bacteria, beta-lactamase, is a major cause of antibiotic resistance.

When patients receive antibiotics, it is doubly dangerous when they lose their native colonic bacteria, because healthcare settings are full of resistant or particularly virulent bacteria.

"So patients are especially vulnerable to acquiring these bacteria within their intestinal tracts," Stiefel said.

Since the Bacteroides, which comprise roughly one quarter of the intestinal microbiome, are absent elsewhere in the body, the investigators believe that the beta-lactamase will not interfere with treatment of infections in other organ systems, such as in the respiratory tract, or the blood.

For example, beta-lactamase enzymes could be given orally as drugs, to protect the gut bacteria from systemic antibiotics.

The research was published in the journal Antimicrobial Agents and Chemotherapy.