Bacterial Pneumonia

Last Updated August 5th, 2021

What is bacterial pneumonia?

It is an inflammation of the lungs, which is caused by some form of bacteria.  There are various types of bacteria that can cause bacterial pneumonia and can be acquired when someone who is infected coughs or sneezes.  The bacteria-filled droplets get into the air and as we breathe them, we get infected.

People who have a weakened immune system have higher chances of acquiring bacterial pneumonia.  Others who are more likely to get infected include people suffering from asthma, emphysema, or heart disease.  Symptoms of bacterial pneumonia may include shortness of breath, greenish mucus, rapid breathing, chest pain with coughing or breathing, as well as lethargy.  Bacterial pneumonia can affect a part of the lung or can affect the entire lung altogether.

Signs and symptoms of bacterial pneumonia

There are several signs and symptoms indicating the presence of bacterial pneumonia and include:

  • High fever ranging up to 105 degrees.
  • Rapid breathing.
  • Chills and shivering.
  • Cough with expectoration of green colored mucus.
  • Coughing or deep breathing can cause severe chest pain.
  • Loss of appetite.
  • Shortness of breath.

Causes of bacterial pneumonia

The most common cause of bacterial pneumonia is due to Streptococcus pneumoniae bacteria.  This type of pneumonia generally occurs after an illness such as cold or flu.  The weakened immune system, respiratory distress, and other illness are the risk factors associated with bacterial pneumonia.  The two main causes of bacterial pneumonia include community-acquired pneumonia and hospital-acquired pneumonia.

Hospital-acquired pneumonia:  It is also called as healthcare-associated pneumonia or nosocomial pneumonia.  It is a lower respiratory infection, which is acquired after a stay at the hospital.  It can be serious because the bacteria causing pneumonia can be resistant to antibiotics.  Hospital-acquired pneumonia is generally acquired when a patient is placed on a breathing machine, on the tracheostomy tube to help breathe, or when the immune system of the patient is weak from disease.

Community-acquired pneumonia:  Typical pneumonia can be considered as community-acquired pneumonia when it is acquired by people with limited or no contact with medical institutions or settings.  The most commonly identified pathogens associated with community-acquired pneumonia are Streptococcus pneumoniae, Haemophilus influenzae, etc.  Symptoms and signs of community-acquired pneumonia include fever, cough, sputum production, pleuritic chest pain, dyspnea, tachypnea, and tachycardia.  Community-acquired pneumonia also includes aspiration pneumonia, which is acquired when a person inhales food, fluid, or vomit into the lungs.  People suffering from swallowing problems are more likely to get aspiration pneumonia. ( Similar to what is mentioned in Aspiration pneumonia)

Bacterial versus viral pneumonia

The most common causes of pneumonia involve either bacteria or virus.  Some of the similarities and differences are discussed below

Bacterial pneumonia in children

In infants, symptoms include difficulty with breathing can be noticed with chest sinking when breathing.  Bluish discoloration of the lips and nails can be noticed indicating an inadequate supply of oxygen.  There are some red flags associated with bacterial pneumonia in children and include high fever up to 102.5 degrees, difficulty breathing, blood in the mucus, confusion, fast heart rate, as well as bluish discoloration of the lips and nails.  Immediate medical attention should be rendered when these symptoms arise to avoid further complications.

Bacteria that cause pneumonia

The most common bacterium causing pneumonia includes Streptococcus pneumoniae.  This type of bacterium enters the body either by inhalation or through the bloodstream.  The second most common cause of bacterial pneumonia is from Haemophilus influenzae.  This bacterium is usually present in the upper respiratory tract and generally do not cause any harm.  A person with a weakened immune system is the one who is likely to be affected by this bacterium.  Other bacteria causing pneumonia include Staphylococcus aureus, Moraxella catarrhalis, Streptococcus pyogenes, Neisseria meningitidis, and Klebsiella pneumonia.

Diagnosis of bacterial pneumonia

Initially, a physical examination is conducted on the patient.  The doctor would examine the patient’s chest with the use of a stethoscope to determine if there are any abnormal sounds related to mucus build-up.  Next, the medical history is reviewed to find out the cause.

Various diagnostic tests are conducted to confirm the diagnosis of bacterial pneumonia.  Generally, the doctor will conduct a chest x-ray to figure out the areas of inflammation and infiltrate in the lungs.  Additional tests such as CT scan and arterial blood gas is done to measure the oxygen and carbon dioxide levels.  A bronchoscopy also may be performed on the patient to collect a biopsy or mucus sample for testing.

Complications of bacterial pneumonia

Complications from bacterial pneumonia may occur depending on the age of the patient and how effective the immune system is.  Both children and adults can develop complications from bacterial pneumonia.  Some of the complications are discussed below.

  • Respiratory failure: A respiratory failure occurs when there is a low level of oxygen and a high level of carbon dioxide.  Due to the infection of the lung by bacteria, it prevents the cells from obtaining oxygen and reduces the ability to breathe adequately.  Both these factors may lead to abnormal function of the lungs leading to respiratory failure.
  • Sepsis: It is a medical condition where the chemicals released in the blood to fight infection causes inflammation throughout the body.  This is considered to be a life-threatening condition that can cause multiple organ failure.
  • Lung abscess: An abscess may be formed when a pocket in the lung becomes infected and there is the formation of pus within the pocket.
  • Pleural empyema: A collection of pus in the pleural cavity is termed as pleural empyema.  This would require drainage of the infected pleural cavity.

Treating bacterial pneumonia

Following the medical examination and diagnosis of pneumonia, treatment for bacterial pneumonia solely is concentrated on targeting the bacterium causing the infection.  This is achieved with the use of antibiotics.  Additional medications to reduce pain and fever are also prescribed.  It is important to complete the course of antibiotics prescribed to avoid any complications.  You will be advised to drink lots of liquids and get plenty of rest until the symptoms subside.

A severe case of bacterial pneumonia would prompt hospitalization for a few days since the patient would require supplemental oxygen with the help of mechanical ventilator due to an inadequate oxygen supply.  Any complications such as respiratory failure, sepsis, lung abscess or pleural empyema would require hospitalization for an extended period of time.


Prevention seems to be the best cure for pneumonia.  This can be achieved by strengthening the immune system of the body.  The immune system can be improved and activated with some lifestyle changes such as eating a healthy diet, maintaining good hygiene, as well as avoiding exposure to people affected by pneumonia.

The first line of defense can be achieved by getting the annual flu shot since pneumonia is considered to be a complication of flu symptoms.  There are vaccines available in the market to protect you against the most common bacterium causing pneumonia called Staphylococcus pneumoniae.  PCV13 and PPSV23 are the two vaccines available that can protect you against 13 and 23 strains of pneumococcal bacterium respectively.

It is recommended that older adults who are 65 years and older should receive both these vaccines whereas children should receive a series of PCV13 vaccine.  You need to contact your doctor who would provide you further details regarding the dosing of the vaccine and their benefits.



  • Bacterial pneumonia may be caused by the germs that already live in your body.
  • Children and old people are at higher risk of acquiring bacterial pneumonia.


  • Getting a flu shot may help prevent pneumonia.
  • Bacteria causing pneumonia are getting more resistant to antibiotics.


  • Pneumonia causes the highest cases of sepsis and septic shock.
  • Streptococcus pneumoniae bacteria are the most common cause of bacterial pneumonia.

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