The Chobanian & Avedisian School of Medicine and Tufts University School of Medicine are hosting the 23rd International Pathogenic Neisseria Conference at the Boston Park Plaza Hotel from Sept. 24-29. The conference brings together hundreds of researchers from around the world who are focused on gonococcal and meningococcal bacteria, two harmful bacteria that are part of the large Neisseria genus that colonize the mucosal tissues of animals.
Most people have heard of the diseases caused by these bacteria. Gonorrhea is one of the most common Sexually Transmitted Infections (STI) worldwide, disproportionately affecting women because of a lack of, or mild, symptoms. Untreated gonorrhea can cause serious and permanent health problems in mainly women, including infertility and ectopic pregnancies.
Meningococcal infections can lead to severe, sometimes fatal, bacterial meningitis, an infection of the lining of the brain and spinal cord. It can also cause the bloodstream infection septicemia, or sepsis, which can lead septic shock. These bloodstream infections can have death rates as high as 50%.
We asked Lee Wetzler, MD, professor of medicine and microbiology a few questions about these diseases and the conference. He has been a conference participant since 1986 and is one of the co-organizers of the current meeting.
Can you give some background information on the conference?
This conference has been held over the last 40 years (the first meeting was in 1978), and it brings together research scientists who investigate pathogenic Neisseria. It’s usually held every two years, typically alternating between North America and Europe.
These are diseases that occur around the world, and we have people coming from five continents and 20 or 30 different countries. Meeting face-to-face with people from all over the world is so important because talking about ways to collaborate is an important function of a conference like this.
The thought leaders in this field all come to this meeting. We have more than 300 people coming, which I was very happy about. It shows how many people are eager to meet in-person again.
The conference was important when we were talking about the meningococcal vaccines in the 1990s, 2000s and it’s important now because gonococcus has been coming to forefront because of the rise of significant antimicrobial resistance. (The conference) really brought the development of a gonococcal vaccine, new therapeutics and diagnostics to the forefront. There’s much more funding dedicated to that and more people coming into the field.
How prevalent are gonococcal and meningococcal infections and the two diseases gonorrhea and meningitis?
Rates of gonococcal infection in the U.S. have increased significantly. In the U.S., there were 710,151 cases of gonorrhea in 2021, the last reported year, but with underreporting you double that usually. There are approximately 80 million annual cases worldwide.
Meningococcal infection is more sporadic than epidemic. It happens usually in conditions where there’s a lot of crowding, like college or in military recruits, which is why the vaccine is sometimes required for incoming college freshmen. Around 1.2 million people are estimated to be diagnosed with invasive meningococcal disease per year, with nearly 135,000 fatalities worldwide. In 2020 in the U.S., 210 cases were reported.
Are there concerns over the rise of antimicrobial resistance in both diseases?
Mainly in gonococcus. We have not seen a rise in antibiotic resistance in the meningococcus. Investigations into why we are seeing it in one and not the other have been ongoing. Some people feel it’s the number of organisms, the microbial burden, and turnover of the organisms, but it’s unclear.
What’s the status on vaccines for the two diseases?
For gonococcus there is no vaccine. A vaccine for meningococcus made from polysaccharides was developed in the early 70s. And then they were conjugated to make them more effective and to allow for a better immune memory.
That vaccine has been around for many, many years. However, there’s one strain called group B, which is not immunogenic (it does not cause or produce an immune response). Only recently has that vaccine been developed.
In meningococcal disease you’re mainly preventing dissemination and meningitis, but it’s really difficult for gonococcus because how you induce immune protection and the mechanism of immune protection are still relatively unknown. That’s the focus of a lot of investigators.
With the reports of increased gonococcal antimicrobial resistance there have been increased efforts for gonococcal (vaccine) development, and the NIH has been giving out more money. There are now centers specifically dedicated to vaccine development against various STI’s and people who are part of that effort are attending the conference.