Antibiotics have a new ally against superbugs

Nanoparticles weaken bacteria’s defenses, giving standard antibiotics a chance against drug-resistant infections.

With antibiotic-resistant superbugs on the rise, the race is on to find new ways to treat patients with multiple-drug resistant infections. A research group at the University of Colorado is working on a promising solution: synthetic nanoparticles that lower superbugs’ defenses, rendering traditional antibiotics effective again. We spoke with Prashant Nagpal and Anushree Chatterjee, the researchers behind the study, to learn more.

ResearchGate: What are superoxide-generating nanoparticles?

Prashant Nagpal and Anushree Chatterjee: Superoxide-generating nanoparticles are very tiny—approximately 10,000 times smaller in width than a human hair—bits of semiconductors, the same material as our computers, solar cells, TVs, etc. The nanoparticles, called quantum dots, are made in solution using chemical precursors and are very scalable in production. These quantum dots were designed to absorb visible light and generate a superoxide inside a cell to increase the power of antibiotics that otherwise wouldn’t work against superbugs.

RG: How do they increase the effectiveness of antibiotics?

Nagpal and Chatterjee: Multiple-drug resistant bacteria can regulate their metabolism and stress response genes to overcome stress caused by antibiotics. But when quantum dots provide a dose of superoxide, the bacterium needs to divert its resources to overcome the superoxide stress, which then makes it vulnerable to the antibiotic.

RG: Can you describe what the experience would be like for a patient being treated this way?

Nagpal and Chatterjee: We are still far away from clinical trials, but we can speculate on how the treatment would be administered. The quantum dots could be taken with the antibiotics—intravenously or through an aerosol—and the patient asked to sit in an illuminated room, outside in the sun, or asked to wear clothing lined with LED lights, and just go through their normal daily routine. The infection should be cleared fast, and the patient will recover.

Credit: Mason Marino / University of Colorado Boulder

RG: What kinds of bacteria could this method be used to treat?

Nagpal and Chatterjee: We have tested our potentiator therapy with a range of different bacteria—gram-positive and gram-negative, from E.coli to Salmonella and MRSA—with varying degrees of resistance—those resistant to two or more drugs, to really potent strains resistant to more than 20 antibiotics. It worked against a large number of tested pathogens, more than 80 percent. We didn’t see any systematic cases where the potentiator does not work. The main difference was the dose required for the strains.

RG: What’s the current stage of this research? When do you expect it could be put into practice?

Nagpal and Chatterjee: Currently, the research has been done in lab cultures, infection modes, and preliminary animal models (nematodes). It will be few years before it can be ready for clinical tests, which would require us to test our potentiator nanoparticles in animals, and then clinical human trials. Since this requires significant financial resources, given adequate support and funds, we could anticipate bringing this to clinical trials in a couple of years.

RG: How does this approach fit into the bigger picture of addressing the problem antibiotic resistance?

Nagpal and Chatterjee: This is part of a two-pronged approach our team has developed to fight antibiotic drug-resistance. In a study published last year, we showed that quantum dots that can be developed as antibiotics to treat infections. This study points to the potential of designed quantum dots to work with existing antibiotics, improving their effectiveness. Our goal is to develop a whole range of antibiotic therapies against resistant superbugs, which can be scaled easily, tailored rapidly, and work with a range of existing solutions (like antibiotics) to prevent further spread of antibiotic resistance. The goal is to keep a few steps ahead of these fast-evolving and honestly very smart bugs, whereas we are currently ten steps or more behind. This would give us a fighting chance in an evolutionary race we cannot afford to lose, since antibiotics are an important pillar of modern medicine and crucial for our survival and health and well-being.

We always want to remind people that antibiotic-resistance is not a future nightmare scenario. It is very real and it exists right now. All the strains we used in our study were from outbreaks in Colorado. The only thing preventing them from being a pandemic infection is their spread, which could turn into a very serious and impending health crisis. So the time to act is now!

Featured image: Micrograph of Methicillin-Resistant Staphylococcus aureus (MRSA). Courtesy of NIAID.