Nourseothricin, a potential new treatment for multi-drug resistant bacterial infections

A recent study published in the open access journal PLOS Biology suggests that an old antibiotic could be a valuable weapon against multi-drug resistant bacterial infections. The research, conducted by James Kirby and colleagues from Harvard Medical School, highlights the potential of nourseothricin, a natural compound derived from a soil fungus.

Nourseothricin was initially discovered in the 1940s and showed promise as a potent agent against Gram-negative bacteria, which are notoriously difficult to eliminate due to their protective outer layer. However, further development was halted due to its toxic effects on the kidneys. With the rise of antibiotic-resistant infections, Kirby and his team revisited nourseothricin as a potential solution.

Previous studies on nourseothricin were hindered by incomplete purification of its various forms, known as streptothricins. Recent advancements allowed researchers to obtain highly purified forms of two different streptothricins, labeled as D and F. Streptothricin-F demonstrated lower toxicity while maintaining high efficacy against contemporary multidrug-resistant pathogens. Both forms exhibited a strong preference for Gram-negative bacteria.

By employing cryo-electron microscopy, the scientists discovered that streptothricin-F extensively binds to a bacterial ribosome subunit. This binding explains the translation errors induced by these antibiotics in target bacteria. Notably, this interaction differs from other known translation inhibitors, suggesting that streptothricin-F could be employed when other agents fail to be effective.

Kirby expressed optimism about the potential of the streptothricin scaffold as a therapeutic approach against multidrug-resistant Gram-negative pathogens. He emphasized its unique and promising activity, stating that further pre-clinical exploration is warranted.

In conclusion, the study highlights the renewed interest in nourseothricin and its streptothricin derivatives as a potential solution for combating drug-resistant bacterial infections. With its powerful activity against resilient pathogens and distinctive mode of action, this old antibiotic holds promise as a valuable tool in the fight against these challenging infections.

Source: Public Library of Science

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