Streptococcus pneumonia: Are you at Risk?

Red blood cells on an agar plate are used to d...

Red blood cells on an agar plate are used to diagnose infection. The plate on the left shows a positive staphylococcus infection. The plate on the right shows a positive streptococcus infection and with the halo effect shows specifically a beta-hemolytic group A. (Photo credit: Wikipedia)

Olivia Rehman (11 AM Micro) found some articles discussing the complex relationship between members of the normal microbiota, and influenza. Here is Olivia’s summary:

While looking at Science Daily, I was interested to find two similar articles that discussed the bacteria Streptococcus pneumonia. While this is typically a harmless bacterium found in the linings of throats and noses of most people, it can quickly cause disease under certain conditions. For years, scientists have been researching the “cause” of this change from harmless to pathogenic.

In April of 2011, scientists had claimed that these bacteria are only able to spread when individuals are infected with the flu. This article titled, “Flu Helps Spread Pneumonia,” goes on to support this theory using infant mice. He found that all mice had to be infected with the flu for the bacteria to spread and that by blocking the flu infection; the mice did not spread the disease.  They explained this phenomenon by stating that flu virus increases the bacterial load in the nose and for others it alters host immunity, making individuals more susceptible. While this study in 2011 may have identified a cause of this disease, a more recent article takes a closer look.

In August of 2013, researchers from the University of Buffalo studied how Streptococcus pneumonia spreads and becomes a virulent pathogen. In this article from Science Daily, the team was looking to find ways to interfere with the disease transmission to possibly block the process and prevent disease from happening. They found that S. pneumonia form biofilms within the nose and cause disease when the bacteria travel to the lungs or the middle ear. By growing biofilms on top of human epithelial cells, they infected the bacteria with influenza A virus, or exposed them to other similar conditions that accompany the flu such as increased temperature, higher amounts of ATP, and the hormone norepinephrine. These stimuli produced a sudden release of the bacteria from the biofilm in the nose into other areas such as the middle ears, lungs or bloodstream. They also noticed that the gene expression of the bacteria revealed more virulence. This causes some sort of “interkingdom” signaling and the bacteria respond to the host molecules. Researchers hope that by finding ways to interrupt the signaling they can prevent this disease from happening altogether.

Currently 80% of children carry the bacteria in their nose and if infected with influenza, are susceptible to life-threatening secondary infections like meningitis, pneumonia and sepsis. Statistics show that more than one million children under the age of five die from S. pneumonia each year. This is just one of the many examples of how opportunistic infections occur and hopefully we will be able to intervene and prevent these deaths in the near future. By looking at articles two years apart, it seems that science is making some advances in their research. While they haven’t found the answer to prevention just yet, they are gaining more knowledge about the organism and gathering a better understanding of how it works. It seems that our best prevention now is to get vaccinated for the flu.


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on November 19, 2013, in Guest Post, Microbes in the News. Bookmark the permalink. 2 Comments.

  1. I was unaware that pneumonia caused so many deaths in children. I always thought that it was not a serious illness and more like the flu in which people get medicine and just get over it. It surprised me that these bacteria are only able to spread when individuals are infected with the flu. If we vacinate most of the population from the flu then the cases of pneumonia should decrease significantly as well. I’m interested to see the outcome of this over the next few years.

    • Pneumonia used to be known as the “Old Man’s Friend,” mainly because it was seen as a relatively painless way to die. Antibiotics have lowered the mortality rate due to pneumonia, so that the major cause of death in that age bracket are things like cardiovascular disease and cancer. With antibiotics losing their efficacy, it is likely that pneumonia will return as a significant cause of death worldwide.

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