Bacterial Pneumonia: Causes, Signs & Treatments

Bacterial Pneumonia: Causes, Signs & Treatments
Coming up next: What Is a Staph Infection? - Causes, Symptoms & Treatments

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:33 Bacterial Pneumonia
  • 1:59 Signs and Symptoms
  • 3:16 Bacteria That Cause Pneumonia
  • 5:07 Diagnosis and Treatment
  • 6:21 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up


Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Artem Cheprasov
This lesson will discuss the causes of bacterial pneumonia. We'll also look into how bacterial pneumonia is diagnosed and treated as well as the common signs and symptoms associated with this condition.

Far Worse Than the Flu

Once, a friend of mine in high school developed what seemed to be a small cold. This then turned into what seemed to be a case of a bad flu. Then my friend didn't show up to class for over two weeks straight. This was no flu. It was something far worse. It caused him terrible chills, incredible and unforgiving thirst, and even required him to be hospitalized just to stay alive!

Bacterial Pneumonia

The havoc wreaked upon my friend's body was all due to something we call bacterial pneumonia. This is an inflammatory condition of the lungs caused by different kinds of bacteria.

The bacteria that cause this inflammation are typically inhaled by their victim. Once they are inhaled, they set up shop in the lungs and trigger something known as the inflammatory response.

Think of it this way - if you were to have a store in a big mall, and someone, like a terrorist, sets up shop next to you, that wouldn't be good for business. You'd probably call mall security or the cops to get rid of that terrorist.

Well, the mall is like your lungs, and the various shops in the lungs are the cells that line and make up the lungs. If bacterial cells enter the lungs, your immune system will try to kick them out.

The way the immune system does this is by recruiting white blood cells, such as neutrophils, to the areas infected with pneumonia-causing bacteria. Once these white blood cells reach the area infected by the bacteria, they, like the police entering a mall to clear it of a terrorist, will begin to fire.

However, instead of firing bullets, the white blood cells release substances that cause vasodilation of local blood vessels and the recruitment of even more inflammatory cells to the area in order to fight off the infection.

Signs and Symptoms

The vasodilation, or widening of blood vessels, causes all sorts of fluids, cells, and molecules to leak into the area to try and kill the bacteria. It's like a whole mixture of mall security, cops, SWAT, and bullets flying into the mall to try and get rid of the terrorist trying to set up shop. Well, as this mall engorges with all sorts of personnel, the mall becomes quite congested.

Similarly, your lungs become congested with bacteria, white blood cells, and fluids, all as a result of the inflammatory response that was initially triggered by the bacteria. This congestion causes you a lot of signs, such as difficulty breathing. In addition, this congestive fluid mixture of cells, bacteria, and molecules involved in pneumonia is what people with pneumonia spit out of their mouth when they cough up the sputum from their lungs.

Besides difficulty breathing and coughing, bacterial pneumonia can cause other signs and symptoms, such as a fever, sweating, chills, and a loss of appetite. All of these factors and more combine together to cause fluid loss from the body, which causes the dehydration and feelings of serious thirst my friend developed.

Bacteria That Cause Pneumonia

The different types of terrorists that can set up shop in a mall are many. Likewise, there are many different kinds of bacteria that may commonly cause bacterial pneumonia. They include:

  • Streptococcus pneumoniae
  • Mycoplasma pneumoniae
  • Legionella pneumophila
  • Chlamydia trachomatis
  • Haemophilus influenzae

This seems like a long list, but I'll give you some tricks that can easily clue you into the fact that these bacteria can cause pneumonia. The word 'pneumonia' refers to the lungs because 'pneumo' means 'lungs' in Greek. Look at the first three types of bacteria I listed:

  • Streptococcus pneumoniae
  • Mycoplasma pneumoniae
  • Legionella pneumophila

I'm positive you can spot the 'pneumo' in each one of them. That'll clue you into the fact that these bacteria are somehow involved with the lung.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account