Scientists found a clever way to fight bacteria that have become resistant to antibiotics. Instead of creating completely new drugs, they tested 2,027 existing medications approved for other diseases to see if they could kill bacteria. Using computer predictions and lab tests, they discovered that a drug called lifitegrast, normally used for eye problems, can stop six types of dangerous bacteria from growing when combined with another compound. This approach, called drug repurposing, could help us fight infections when traditional antibiotics stop working.
The Quick Take
- What they studied: Can we use existing medications (not designed as antibiotics) to kill drug-resistant bacteria by testing them against bacterial proteins?
- Who participated: The study tested 2,027 approved non-antibiotic drugs and 173 existing antibiotics against six types of dangerous bacteria commonly found in hospitals and infections.
- Key finding: A drug called lifitegrast, when combined with a helper compound, successfully stopped the growth of six types of gram-negative bacteria at low doses in lab tests.
- What it means for you: This suggests a new strategy for fighting antibiotic-resistant infections, but these results are from lab tests only. Much more research is needed before this could be used in patients.
The Research Details
Scientists used a three-step approach to find new antibacterial drugs. First, they used computer software to predict which of 2,027 existing approved drugs might attach to and disable 125 essential bacterial proteins. This narrowed down thousands of possibilities to just 14 promising candidates. Second, they tested these 14 drugs in the laboratory against six types of dangerous bacteria to see which ones actually killed or stopped bacterial growth. Third, they used advanced techniques like surface plasmon resonance and molecular simulations to understand exactly how the most promising drug (lifitegrast) was working against the bacteria.
This approach is important because it’s much faster and cheaper than developing completely new antibiotics from scratch. By testing drugs already approved for human use, scientists can skip many safety steps and focus on finding new uses for existing medications. This is especially critical because bacteria are becoming resistant to our current antibiotics, and we need new solutions quickly.
This is a preliminary laboratory study, which means the results are promising but not yet proven in humans. The researchers used established scientific methods and multiple validation techniques to confirm their findings. However, the study was conducted in controlled lab conditions with pure bacterial cultures, which is very different from how infections work in the human body. The results need to be confirmed in more complex studies before any clinical use.
What the Results Show
Among the 2,027 non-antibiotic drugs tested, several showed the ability to kill or stop bacterial growth. The most successful candidate was lifitegrast, a drug normally used to treat dry eyes. When lifitegrast was combined with a helper compound called PMBN at a low dose of 8 micrograms per milliliter, it effectively stopped the growth of all six types of gram-negative bacteria tested in the laboratory. These bacteria included E. coli, Pseudomonas aeruginosa, and Acinetobacter baumannii—all common causes of serious hospital infections. The researchers also discovered that existing antibiotics could be grouped into two categories based on how they attach to bacterial proteins, and these groups showed different levels of effectiveness against bacteria.
The research revealed that lifitegrast works by blocking a bacterial protein called FolA, which bacteria need to survive and reproduce. When this protein is disabled, the bacteria cannot make the molecules they need to grow. This mechanism was confirmed through folate rescue experiments, where adding folate (a B vitamin) partially restored bacterial growth, proving that FolA inhibition was the key mechanism. The study also showed that the computer prediction method was useful for identifying which drugs might have antibacterial properties, suggesting this approach could be used to screen other drug libraries in the future.
This research builds on the growing field of drug repurposing, which has successfully found new uses for existing medications in other areas of medicine. The approach of using computer predictions combined with laboratory testing is becoming more common in antibacterial research as scientists search for alternatives to traditional antibiotic development. However, this is one of the first studies to systematically test such a large library of non-antibiotic drugs specifically for antibacterial activity, making it a novel contribution to the field.
This study has several important limitations. First, all testing was done in laboratory dishes with pure bacterial cultures, not in living organisms or humans. Second, the study only tested lifitegrast at specific concentrations and didn’t fully explore how different doses might affect human cells or cause side effects. Third, the research focused only on gram-negative bacteria; effectiveness against other types of bacteria is unknown. Fourth, the study didn’t test whether bacteria might develop resistance to lifitegrast over time. Finally, the mechanism of action needs further investigation to fully understand how lifitegrast affects bacterial cells.
The Bottom Line
Based on this preliminary research, drug repurposing appears to be a promising strategy for discovering new antibacterial compounds. However, these findings are from laboratory studies only. Before lifitegrast or any other repurposed drug could be used to treat infections in patients, it would need to go through extensive testing in animals and then human clinical trials to confirm safety and effectiveness. Current confidence level: Low to Moderate (preliminary laboratory evidence only).
This research is most relevant to pharmaceutical companies, researchers, and healthcare professionals looking for new ways to combat antibiotic-resistant infections. Patients with serious drug-resistant bacterial infections should be aware that new treatment options are being researched, but they should not expect these drugs to be available soon. People taking lifitegrast for dry eyes should not change their use based on this research.
If this research progresses as hoped, it would take several years of additional testing before lifitegrast or similar repurposed drugs could potentially be used to treat bacterial infections in patients. Typical timelines for drug development are 5-10 years from laboratory discovery to clinical use.
Want to Apply This Research?
- Users interested in antibiotic resistance could track their antibiotic use and prescription history to understand their personal exposure to antibiotics, helping them make informed decisions with their healthcare providers about when antibiotics are truly necessary.
- Users could set reminders to complete full courses of prescribed antibiotics as directed, which helps prevent antibiotic resistance from developing. They could also log when they practice infection prevention measures like handwashing to reduce the need for antibiotics in the first place.
- Over time, users could monitor trends in their infection frequency and antibiotic prescriptions, sharing this data with their healthcare provider to identify patterns and discuss prevention strategies. This long-term tracking helps users understand their personal infection risk and the importance of antibiotic stewardship.
This research describes preliminary laboratory findings and does not represent approved medical treatment. Lifitegrast is currently approved only for dry eye disease and should only be used as prescribed by a healthcare provider for that indication. These laboratory results do not indicate that lifitegrast is safe or effective for treating bacterial infections in humans. Anyone with a bacterial infection should consult their healthcare provider for appropriate treatment. Do not attempt to use any medication off-label based on this research without explicit guidance from a qualified healthcare professional. This information is for educational purposes only and should not be used for self-diagnosis or self-treatment.