On April 5, 2024, a study from a Swedish university revealed a new class of antibiotics effective against multidrug-resistant bacteria, showing promise in treating bloodstream infections in mice. Published in *Proceedings of the National Academy of Sciences*, the discovery is significant due to the rising challenge of antibiotic resistance, particularly against gram-negative bacteria.

Importance of New Antibiotics
Antibiotics are crucial in modern medicine, but resistance threatens their effectiveness. The development of new antibiotics is vital for expanding treatment options and safeguarding public health, especially during surgeries.
 

Characteristics of the New Antibiotic

The antibiotics found in this study have potent antimicrobial activity against gram-negative bacteria by targeting the lipopolysaccharide synthesis pathway of bacteria. This pathway is necessary in most gram-negative bacteria and there is no analogue in humans, so this class of antibiotics is selective for bacteria. This new class of antibiotics acts on a protein called LpxH, which synthesizes the outermost protective layer, lipopolysaccharides, in gram-negative bacteria. These antibiotics have shown great potential for the successful treatment of bloodstream infections in mouse models with high activity against multidrug-resistant bacteria.

Specifically, this class of antibiotics is optimized to be active against wild-type bacterial strains (with efflux function) and can effectively inhibit bacteria expressing drug-resistant genes such as broad-spectrum β-lactamase, metallo β-lactamase, and carbapenemase. There is no pre-existing resistance in clinical isolates, so it is still effective against "superbugs" that have evolved in the direction of current resistance mechanisms. In vivo, it has a strong effect on bloodstream infections caused by E. coli and Klebsiella. In conclusion, this new class of antibiotics is characterized by specificity, potency, and lack of existing resistance, which is expected to provide a new solution to the challenge of antibiotic resistance.

Challenges Ahead
Despite their potential, developing these antibiotics into approved drugs involves complex and lengthy processes, including laboratory studies, preclinical trials, and several phases of clinical trials, often taking at least five years.

In a word, this new class of antibiotics presents exciting possibilities for treating a range of gram-negative infections and may improve therapeutic outcomes when used with other antibiotics, offering hope against antibiotic resistance.