--- title: "Colistin Resistance Compromises Last-Resort Antibiotic Efficacy" url: https://newscentral.site/colistin-resistance-compromises-last-resort-antibiotic-efficacy/ language: en publisher: "News Central Site" section: "Science" published: 2026-10-29T13:00:01.000Z updated: 2026-10-29T13:53:01.845Z id: ce3a14e5-5d40-4056-9d49-52dff0c36d86 source: "Phys.org https://phys.org/news/2026-10-amino-acid-boosts-resort-antibiotic.html" attribution: "Link to https://newscentral.site/colistin-resistance-compromises-last-resort-antibiotic-efficacy/ and name News Central Site when you quote or summarize this story." --- # Colistin Resistance Compromises Last-Resort Antibiotic Efficacy Researchers have discovered a promising approach to overcoming antibiotic resistance by combining colistin with L-arginine, an amino acid found naturally in the body. Millions of people die each year due to antibiotic resistance worldwide, a trend that is being closely monitored by the World Health Organization. The organization warns that the number of resistant infections is rising, which puts patients at greater risk when they are treated with last-resort antibiotics like colistin. Colistin is often used as a last resort when other treatments fail, but its effectiveness is also being compromised by increasing rates of resistance. In fact, the rise in colistin-resistant infections has made it even more urgent to find new ways to combat these pathogens. Researchers in China have discovered a promising approach that involves combining colistin with L-arginine, an amino acid found naturally in the body. This combination has shown potential in restoring sensitivity to colistin in bacteria that are resistant to its effects. Lab and animal studies suggest that this treatment works by altering the cell membrane of the bacterium, allowing colistin to penetrate more easily and trigger a response that ultimately kills the microbe. A team of researchers has identified a promising approach to overcoming antibiotic resistance by combining a last-resort medication with an amino acid. Colistin was initially approved in 1959 for treating severe infections caused by gram-negative bacteria, but its use was limited due to toxicity and severe side effects. However, the emergence of superbugs resistant to powerful antibiotics led to increased reliance on colistin as a therapeutic option. The problem is further complicated by the spread of genes conferring resistance through small circular DNA segments called plasmids. To combat this issue, scientists have explored various strategies for resensitizing bacteria to colistin. Some researchers have combined the antibiotic with nanomaterials or other medications, while others have investigated metabolites produced during metabolism as potential boosters due to their ability to alter interactions between pathogens and antibiotics. The study focuses on L-arginine, an amino acid that has previously shown promise in enhancing the efficacy of certain antibiotics. The researchers found that combining colistin with L-arginine was effective in killing strains of Escherichia coli harboring the mcr-1 gene, which drives resistance to colistin. The combination of colistin and L-arginine proved to be a potent antibacterial treatment when administered together, but showed minimal activity when used separately. This dual-targeted approach offers a promising strategy for overcoming antibiotic resistance and potentially saving lives. Researchers tested the combination of the last-resort antibiotic colistin and the amino acid L-arginine on mice infected with a colistin-resistant strain of E. coli in the peritoneum. The results showed that 80% of treated mice survived after 72 hours, significantly higher than the survival rates for those given either treatment alone. The combination therapy was not only effective in increasing survival rates but also led to a significant reduction in pathogenic bacteria in major organs. Scanning electron microscopes and other imaging methods revealed changes in the size and structure of the bacteria, including alterations to their cell membranes. Further analysis using transcriptome sequencing shed light on the mechanism behind the drug combination's effectiveness. The researchers found that L-arginine amplifies the membrane-damaging effects of colistin by downregulating certain genes related to metabolism. The findings suggest that disrupting bacterial membranes with this combination could be a promising therapeutic approach, but more testing is needed to ensure its safety and efficacy in humans. Additionally, it remains unclear whether the results will translate to all strains of resistant bacteria. The discovery of a combination that enhances the effectiveness of last-resort antibiotics has sparked optimism among researchers. By pairing a certain amino acid with this critical medication, its benefits can be preserved. This approach is seen as readily translatable to various applications, offering new hope for combating resistant bacterial strains. The potential impact on public health is significant, but further research is needed to confirm the results' universality across different strains of bacteria. --- Source: [Phys.org](https://phys.org/news/2026-10-amino-acid-boosts-resort-antibiotic.html) Published by News Central Site: https://newscentral.site/colistin-resistance-compromises-last-resort-antibiotic-efficacy/