Bacteria Versus Bacteria Creates New Antibiotic

Biologists at the Massachusetts Institute of Technology were able to find a new type of antibiotic, when soil-dwelling bacteria was made to fight against another strain of bacteria.

This ‘battle for survival’, the researchers say, has led to the new antibiotic that holds promise as a treatment for Helicobacter pylori that causes stomach ulcers in humans.

As a part of the study, the researchers provoked Rhodococcus, a soil-dwelling bacteria, into producing the antibiotic by forcing them to grow in the presence of a competing bacteria, a strain of Streptomyces that produces an antibiotic that normally kills other bacteria.

They found that in one of the experimental test tubes, Rhodococcus started producing its own antibiotic, which killed off the Streptomyces.

This was then isolated and named rhodostreptomycin.

When it was further tested, the researchers found that it proved effective against many other strains of bacteria, most notably Helicobacter pylori.

“Even if (rhodostreptomycin) is not the best antibiotic, it provides new structures to make chemical derivatives of. This may be a starting point for new antibiotics,” said Philip Lessard, research scientist in Professor Anthony Sinskey's laboratory at MIT where the research was conducted.

What still remains a mystery however, is why Rhodococcus started producing this antibiotic.

As the version of Rhodococcus that produced the antibiotic had a “megaplasmid,” or large segment of extra DNA, that it received from Streptomyces, one theory suggests that the presence of the rival bacteria raised an alarm, thus turning on new genes.

However, the researchers having sequenced more than half of the plasmid, found no genes that correlate to the antibiotic.

Another theory suggests that the plasmid itself served as the “insult” that provoked Rhodococcus into producing the antibiotic.

A third theory suggests that some kind of interaction of the two bacterial genomes produced the new antibiotic.

The researchers believe that if they or other scientists could find out what caused Rhodococcus to produce the antibody, they could manipulate bacterial genomes in a more methodical fashion to design new antibiotics.

The research is reported in the February issue of the Journal of the American Chemical Society.

Source-ANI
SUN/L