Nav: Home

Pneumococcal DNA predicts course of infection

July 04, 2018

Pneumococcus (Streptococcus pneumoniae) is an important cause of pneumonia, sepsis and meningitis. This bacterium commonly resides in the nasal cavity. Normally, this is not a problem but it can make weak patients very ill, quite often with a fatal outcome. Patient characteristics such as age, compromised immune system and comorbidity partly explain why some patients develop pneumonia and others meningitis. It was not known whether properties of the pneumococcus itself also determine how invasive pneumococcal disease manifests itself.


Pneumococci show huge genetic variability. This variation is often denoted using antibodies (sera) which recognize specific sugar capsules on the pneumococcal surface. More than ninety of such sugar capsules (serotypes) are known. Although there is a relationship between these serotypes and the course of the disease, the variation in pneumococci is not restricted to these differences in sugar capsules. Therefore, researchers at the Radboudumc in collaboration with the RIVM, CWZ, Maasziekenhuis Pantein, Imperial College London and the Sanger Institute in Cambridge have determined the entire DNA sequence of pneumococci isolated from the blood of 350 patients. They could subsequently relate the genetic variation they found to more than twenty disease manifestations.

Blood-brain barrier

The researchers found several bacterial genes which appeared to be linked to the course of the infection. The presence of the slaA gene, for example, appeared to predict meningitis. This gene codes for the phospholipase A2 protein. Earlier research suggests that this protein is involved in inflammation and may also affect the blood-brain barrier. Bacteria carrying this gene could therefore be able to penetrate the brain. Another set of four genes predicted whether a patient would die within 30 days, particularly among those who were not expected to die at first sight. Marien de Jonge, head of the section Pediatric Infectious Diseases at the Radboudumc: "Earlier we found that one of these genes codes for a protein that activates blood platelets, which could lead to excessive blood clotting and an increased risk of death." The genes identified were also found in a second group of 500 patients.

Risk assessment

The pneumococcal genes found can also be measured in the blood of patients. This provides diagnostic opportunities, says Amelieke Cremers, clinical microbiologist in training and first author of the article: "This study shows that modern DNA sequencing techniques can be used to improve the diagnostics of infectious diseases. Knowledge of the genetic variation within bacterial species can improve our risk assessment for individual patients with acute infections."

Radboud University Medical Center

Related Infectious Diseases Articles:

Certain antidepressants could provide treatment for multiple infectious diseases
Some antidepressants could potentially be used to treat a wide range of diseases caused by bacteria living within cells, according to work by researchers in the Virginia Commonwealth University School of Medicine and collaborators at other institutions.
Opioid epidemic is increasing rates of some infectious diseases
The US faces a public health crisis as the opioid epidemic fuels growing rates of certain infectious diseases, including HIV/AIDS, hepatitis, heart infections, and skin and soft tissue infections.
Infectious diseases could be diagnosed with smartphones in sub-Saharan Africa
A new Imperial-led review has outlined how health workers could use existing phones to predict and curb the spread of infectious diseases.
The Lancet Infectious Diseases: Experts warn of a surge in vector-borne diseases as humanitarian crisis in Venezuela worsens
The ongoing humanitarian crisis in Venezuela is accelerating the re-emergence of vector-borne diseases such as malaria, Chagas disease, dengue, and Zika virus, and threatens to jeopardize public health gains in the country over the past two decades, warn leading public health experts.
Glow-in-the-dark paper as a rapid test for infectious diseases
Researchers from Eindhoven University of Technology (The Netherlands) and Keio University (Japan) present a practicable and reliable way to test for infectious diseases.
Math shows how human behavior spreads infectious diseases
Mathematics can help public health workers better understand and influence human behaviors that lead to the spread of infectious disease, according to a study from the University of Waterloo.
Many Americans say infectious and emerging diseases in other countries will threaten the US
An overwhelming majority of Americans (95%) think infectious and emerging diseases facing other countries will pose a 'major' or 'minor' threat to the U.S. in the next few years, but more than half (61%) say they are confident the federal government can prevent a major infectious disease outbreak in the US, according to a new national public opinion survey commissioned by Research!America and the American Society for Microbiology.
Decline in deaths from most infectious diseases in US, large differences among counties
Deaths due to most infectious diseases decreased in the United States from 1980 to 2014, although there were large differences among counties.
AI to fight the spread of infectious diseases
Public outreach campaigns can prevent the spread of devastating yet treatable diseases such as tuberculosis (TB), malaria and gonorrhea.
Increasing public awareness is vital in the fight against infectious diseases
Public awareness campaigns on spotting the signs and symptoms of infectious diseases and how to prevent them, play a key role in helping to stop the spread of such infections, a new study in the journal Epidemiology and Infection reports.
More Infectious Diseases News and Infectious Diseases Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#540 Specialize? Or Generalize?
Ever been called a "jack of all trades, master of none"? The world loves to elevate specialists, people who drill deep into a single topic. Those people are great. But there's a place for generalists too, argues David Epstein. Jacks of all trades are often more successful than specialists. And he's got science to back it up. We talk with Epstein about his latest book, "Range: Why Generalists Triumph in a Specialized World".
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at