Bacteria+in+Us

Streptococcus pneumoniae is a species of "true" bacteria which is responsible for, as you guessed, pneumonia, but also many other pneumococcal infections, which include meningitis, sepsis, sinusitis, and brain abscess. Its common name is pneumococcus.  Streptococcus pneumoniae [Electronic Image]. Retrieved November 12, 2010, from:

The phylum to which this species belongs is Firmicutes. This phylum contains bacteria that are gram-postive and nonbranching. This means that when dyed, these bacteria will retain the dark-purple colour and lack an extra outer membrane. The phylum includes rod-shaped and cocci bacteria. Pneumococci (the plural form) are slightly elongated, spherical and smooth unicellular organisms that generally live in the upper human respiratory tract. They can either be unicellular or can grow in chains. The bacteria have six cell wall layers and small hair-like structures called pili on their surfaces. The pili help the bacteria colonize better and help them form large groups, which helps in invading a human respiratory system effectively. These bacteria can only flourish and reproduce after the host human has been slightly weakened by other diseases or infections. The common cold, for example, which is a viral infection, causes the human to produce too many liquids and fluids. These liquids allow the pneumococci the grow and live well.

Pneumococci have adapted well to prosper in its situation. They, to attack its host, release a toxin called pneumolysin, which ruins and destroys the blood vessels that are found in the lungs. Once they are destroyed, blood leaks into the areas for air in the lungs. When there is no more room for air, the human dies from the inability to breathe. Even antibiotics are not effective against this bacterium because causing the breaking of the cells will only allow more of the toxins to be released. That is one of the reasons pneumonia and similar diseases were and still are so deadly to humans. Also, pneumococci have an interesting natural transformation system which allows them to exchange genetic information with each other. This builds up resistance to medications or antibiotics. They also grow extremely quickly in environments that are suitable, like a human sick with a common cold. This allows them to "mutate" very quickly and build up immunity to antibiotics. They are selectively bred in that the strong and resistant bacteria survive and reproduce while the weak and non-resistant die off. Another self-defense mechanism these bacteria have is the ability to autolyse. When faced with an antimicrobial drug or medicine, they will kill themselves off, releasing the parts of their cell walls. These parts are toxic and cause further inflammation in the host.

Pneumococci can live in any human being that has been weakened, likely by a viral infection. Therefore, as long as there is a suitable host for the pneumococci, it can survive virtually anywhere on the planet.

Gram Stain of a film of sputum from a case of lobar pneumonia [Electronic Media]. Retrieved November 12, 2010, from: []

The taxonomy of this species: Eubacteria Firmicutes Bacilli Lactobacillales Streptococcaceae Streptococcus pneumoniae

A computer-generated video of pneumococcus: media type="youtube" key="GO3tIhoZvOo?fs=1" height="385" width="640"

An educational video to help you remember things about pneumococcus: media type="youtube" key="mzvBc8gQyOw?fs=1" height="385" width="480"


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 * Wikipedia**. (2010). //Streptococcus pneumonia.// Retrieved November 12, 2010, from: h[|ttp://en.wikipedia.org/wiki/Gram-positive_bacteria]