Nasal drops of harmless bacteria can inhibit a related bug that sometimes causes meningococcal disease, according to new findings published online in Clinical Infectious Diseases. The study -- conducted among college students, a group at higher risk for this often serious illness -- suggests a new approach that could help suppress outbreaks of the disease, if supported by future research.
Meningococcal disease is caused by Neisseria meningitidis, which can infect the lining of the brain and the spinal cord, causing meningitis. Strains of the bacteria can also cause serious bloodstream infections. But N. meningitidis can also live silently in a person's nose and throat, without illness. These "colonized" carriers can spread the pathogen to others through close contact.
In the study, researchers placed drops containing low doses of Neisseria lactamica, a related but harmless bacterial strain, into the noses of 149 healthy university students in the United Kingdom. A control group of 161 students received drops of saline instead. Nose swabs were taken at regular intervals over six months and tested for both types of bacteria.
Among students who received the N. lactamica drops and became colonized, the harmless bacteria appeared to prevent N. meningitidis from colonizing the students' throats. The "good" bacteria also displaced the worrisome pathogen in those who were already carrying it when the study began. The effect was seen after just two weeks, when the number of students carrying N. meningitidis in their upper airway dropped by 9.5 percent among those who were also colonized by N. lactamica using the drops. The effect lasted for at least four months.
"It's the first time that anyone has taken a bug--a friendly bacterium--and has shown that it changes the way that you can become colonized by the meningitis bacterium, Neisseria meningitidis," says study author Robert C. Read, MD, of the University of Southampton in the United Kingdom, who described the study as a "proof of principle" with intriguing implications.
Meningococcal vaccines induce high levels of antibodies in the blood to ward off infection, but current vaccines also limit "carriage" of N. meningitidis in the throat, preventing its spread from one person to another. The drop in carriage seen in this study was faster and more persistent than that seen after vaccination. The harmless bacterial strain was also active against more varieties of N. meningitidis.
The findings suggest that N. lactamica may one day help suppress meningococcal outbreaks as a bacterial medicine. Before then, Read notes, more research is needed, including to confirm that N. lactamica is entirely harmless in a wide population and that it does not change genetically while living in the airway. Determining how to improve carriages rates of N. lactamica also will be necessary before the approach can advance, Read says.
Source: Infectious Diseases Society of America
The Next Frontier in Infection Control: AI-Driven Operating Rooms
Published: July 15th 2025 | Updated: July 15th 2025Discover how AI-powered sensors, smart surveillance, and advanced analytics are revolutionizing infection prevention in the OR. Herman DeBoard, PhD, discusses how these technologies safeguard sterile fields, reduce SSIs, and help hospitals balance operational efficiency with patient safety.
Targeting Uncertainty: Why Pregnancy May Be the Best Time to Build Vaccine Confidence
July 15th 2025New national survey data reveal high uncertainty among pregnant individuals—especially first-time parents—about vaccinating their future children, underscoring the value of proactive engagement to strengthen infection prevention.
CDC Urges Vigilance: New Recommendations for Monitoring and Testing H5N1 Exposures
July 11th 2025With avian influenza A(H5N1) infections surfacing in both animals and humans, the CDC has issued updated guidance calling for aggressive monitoring and targeted testing to contain the virus and protect public health.
IP LifeLine: Layoffs and the Evolving Job Market Landscape for Infection Preventionists
July 11th 2025Infection preventionists, once hailed as indispensable during the pandemic, now face a sobering reality: budget pressures, hiring freezes, and layoffs are reshaping the field, leaving many IPs worried about their future and questioning their value within health care organizations.