Welcome to Study of the Week from Patient Worthy. In this segment, we select a study we posted about from the previous week that we think is of particular interest or importance and go more in-depth. In this story we will talk about the details of the study and explain why it’s important, who will be impacted, and more.
If you read our short form research stories and find yourself wanting to learn more, you’ve come to the right place.
This week’s study is…
Neisseria species as pathobionts in bronchiectasis
We previously published about this research in a story titled “Neisseria Bacteria Cause Worsening Bronchiectasis” which can be found here. The study was originally published in the scientific journal Cell Host & Microbe. You can read the full text of the study here.
This research team was affiliated with the Nanyang Technological University, Singapore.
What Happened?
Patients living with bronchiectasis, an uncommon type of lung disease, are vulnerable to infections. Bacteria of the genus Neisseria, which are commonly found in the human body, also frequently turn up as a component of the microbiome in bronchiectasis. In the past, the presence of this bacteria was not considered a contributor to the disease. However, this research team found that patients that had Neisseria bacteria in their bronchiectasis biome had worse outcomes and more disease exacerbations.
The team was driven to conduct the research due to evidence that the disease tends to worsen more rapidly in older patients of Asian descent. The researchers looked at data from 225 Asian patients and compared it to patients of European descent. Neisseria bacteria have been linked to infectious diseases before, such as meningitis and gonorrhea. However, they have not historically been associated with lung diseases.
The team compared the microbiome data from the two groups of patients and found that the Asian patients with the worst disease progression and exacerbations tended to have a lot of Neisseria in their bronchiectasis microbiome. The effect was strongest in patients with Neisseria subflava. These patients had repeated episodes of infection and more severe overall disease. Further investigation using animal and cell models revealed that this bacterium causes cell disruptions that trigger immune dysfunction and inflammation.
This was the first time that this genus of bacteria has been implicated in a lung disease, and the team also found that Neisseria was also present in chronic obstructive pulmonary disease (COPD) and severe asthma. Further study of the homes of the patients that had high levels of the bacteria found that it was present in the home environment. The scientists believe that a tropical environment is favorable for the growth of Neisseria and may help explain why it was more common in the Asian patients.
About Bronchiectasis
Bronchiectasis is a disease of the lung which is most characterized by the permanent enlargement of certain areas of the lung’s air passages. This illness can be both acquired or congenital. It often appears as the result of other diseases, such as cystic fibrosis, pneumonia, tuberculosis, and many others. Heroin, alcoholism, and inhalation of toxic gases like ammonia can also increase the risk. There are also several genetic disorders and conditions that increase the risk, such as immunodeficiency, Marfan syndrome, and Young’s syndrome. In many cases, the cause is unknown. Symptoms include coughing up mucus, lung infections, clubbed digits, wheezing, chest pain, coughing up blood, and shortness of breath. Treatments include inhaled steroids, postural drainage, antibiotics, and surgery. The exact frequency of this disease is not well known. To learn more about bronchiectasis, click here.
Why Does it Matter?
The discoveries made in this study help the medical world gain a greater understanding of the drivers of bronchiectasis. The identification of Neisseria bacteria as a risk factor for more severe disease is of special importance to patients of Asian descent. To begin with, bronchiectasis has been found to be more common in Asian populations. In fact, the disease is four times more common in Asians than in Europeans. In about half of cases in Singapore, the cause of the disease is unknown.
“Our findings have established, for the first time, that poorer clinical outcomes such as greater disease severity, poorer lung function and high repeated infection rates among bronchiectasis patients are closely associated to the bacteria Neisseria and that this finding is especially important for Asian patients.” – Sanjay Chotirmall, lead investigator, LKCMedicine Associate Professor, Provost’s Chair in Molecular Medicine
The findings will also have an impact on how bronchiectasis is treated. In patients with a worse than normal case, this bacterium now must be considered a potential cause. Testing to determine the presence of Neisseria will be critical. This could result in more personalized treatments that could improve outcomes, particularly for Asian patients who are more at risk of having this bacterium.
