Decades old Antibiotics could prevent drug-resistant superbugs

In time to fight deadly bacterial strains, an antibiotic from the 1940s might make a stunning comeback. Scientists previously discarded this 80-year-old medicine, but a new study suggests it may offer protection against antibiotic-resistant superbugs.

It is derived from a complex molecule called streptothricin, a natural product produced by soil fungi. The discovery of this antibiotic in the 1940s raised optimism that it would prove to be an effective weapon against gram-negative bacteria, which are difficult to treat with other antibiotics due to their tough outer shells. Nourseothricin has, however, been discontinued due to its toxic effects on the kidneys.

Nonetheless, antibiotic-resistant bacteria have necessitated the development of new medications. As a result, Harvard Medical School pathology professor James Kirby and his colleagues reexamined nourseothricin. In his view, earlier studies of nourseothricin suffered from insufficient streptothricin purification.

In recent research, it has been found that streptothricins have different levels of toxicity. The streptothricin-F form is significantly less toxic while remaining highly effective against multidrug-resistant bacteria.

Researchers examined the antibacterial activity, kidney toxicity, and mechanism of action of streptothricins D and F purified forms. A professor stated that the D form was more effective against drug-resistant Enterobacterales and other bacterial species, but it induced kidney toxicity at lower doses.

Streptothricin-F, an antibacterial antibiotic, significantly binds to a bacterial ribosome subunit using cryo-electron microscopy. This may explain why these antibiotics cause translation errors in their target bacteria.

The findings are published in the journal PLOS Biology.