Researchers have found that nasal drops of a
"good" bacterial strain can help prevent the deadly disease
meningitis. The findings could lead to a new approach that could help suppress
meningitis outbreaks.
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.
Meningitis can be life threatening and the first symptoms of the disease are usually fever, vomiting, headache and feeling unwell.
In the study, published online in the journal Clinical Infectious Diseases, researchers placed drops containing low doses of Neisseria lactamica, a related but harmless bacterial strain, into the noses of 149 healthy university students in Britain.
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.
Meningitis can be life threatening and the first symptoms of the disease are usually fever, vomiting, headache and feeling unwell.
In the study, published online in the journal Clinical Infectious Diseases, researchers placed drops containing low doses of Neisseria lactamica, a related but harmless bacterial strain, into the noses of 149 healthy university students in Britain.
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
colonised, the harmless bacteria appeared to prevent N meningitidis from
colonising 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 colonised by N lactamica using the drops. The effect lasted for at least four months, the researchers noted.
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 colonised by N lactamica using the drops. The effect lasted for at least four months, the researchers noted.
"It is the first time that anyone has taken a bug -- a
friendly bacterium -- and has shown that it changes the way that you can become
colonised by the meningitis bacterium, Neisseria meningitidis," said study
author Robert Read from University of Southampton.
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 be used as a bacterial medicine to help suppress meningococcal outbreaks. Before then, Dr. Read noted, more research is needed, including confirming 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, Dr. Read said.
Sources