Bacterial pneumonia is an inflammation of the lungs due to bacterial infection. Different types of bacteria can cause pneumonia. This type of pneumonia can occur in both lungs, one lung, or one section of a lung.

Pneumococcal disease, which Streptococcus pneumoniae causes, is a major cause of bacterial pneumonia. In the United States, it occurs in around 900,000 people each year, and approximately 400,000 of these require admission to a hospital.

Pneumococcal pneumonia is fatal in roughly 5­-7 percent of people who stay in hospital for treatment.

Other types of bacteria can cause pneumonia and significant harm, alongside other types of pathogen, including viruses, parasites, and fungi.

In this article, we look at the symptoms, causes, and treatments of bacterial pneumonia, as well as how to prevent the disease.

Pneumonia causes chest painShare on Pinterest
Pneumonia might cause chest pain or shortness of breath.

The severity of bacterial pneumonia symptoms can vary. Some people only experience mild symptoms while others develop life-threatening complications.

According to the American Lung Association, typical symptoms of bacterial pneumonia include:

  • chest pain
  • shortness of breath
  • a cough that may produce yellow or green mucus
  • fever
  • tiredness
  • chills

Symptoms of bacterial pneumonia tend to be similar in both children and adults. According to the American Academy of Pediatrics, toddlers and infants may cry more than usual, have reduced energy, and appear pale.

A person who suspects symptoms of pneumonia should seek medical attention. The cause of a particular presentation of pneumonia can be difficult to determine without seeing a physician.

Since the treatments for bacterial and viral pneumonia are different, finding the correct cause is vital for choosing the appropriate treatment regimen.


Bacterial pneumonia might be complicated in both children and adults. Anyone can develop complications from bacterial pneumonia, but people with weaker immune systems, younger children, and older adults have a higher risk.

Complications may include the following:

  • Respiratory failure: This might develop if oxygen levels in the lungs drop too low or if carbon dioxide levels spike. It can occur due to inadequate breathing ability, and respiratory failure may even cause lung function to stop completely.
  • Sepsis: This occurs when an infection causes an overwhelming inflammatory response throughout the body. Sepsis can lead to failure in multiple organs and may be life-threatening.
  • Lung abscess: This occurs when an infected pocket of pus forms in the lung.
  • Empyema: This is an infectious collection of pus in the pleural cavity that surrounds the outside of lungs

Swift treatment is vital for reducing the risk of complications.

Small air sacs called alveoli are within the lobes of each lung. Normally, these air sacs aid in the body’s gas exchange, while inhaling oxygen and exhaling carbon dioxide.

When a person develops pneumonia, the air sacs experience inflammation, which can cause them to fill with fluid. If the air sacs fill with fluid rather than air, breathing might become difficult.

In some cases, the lungs and the rest of the body may not get enough oxygen.


Pneumonia is often classified as either community-acquired pneumonia or hospital-acquired pneumonia. The classification refers to the location in which a person acquired the infection.

Community-acquired pneumonia is the by far more the common type. Other, less common types can occur, such as healthcare-associated pneumonia (HCAP) and ventilator-associated pneumonia (VAP).

If a person develops community-acquired pneumonia, it means infection occurred outside of a hospital. The pneumococcal bacterium usually enters the lungs after a person breathes in particles or droplets from a sneeze or cough from another individual who has the infection.

Amongst the most common causes of community-acquired pneumonia are bacteria, including Streptococcus pneumoniae, the most common bacteria, and Haemophilus influenzae.

However, viruses, including influenza viruses, can also cause community-acquired pneumonia.

Hospital-acquired pneumonia develops while in the hospital and occurs after at least 48 hours of being admitted.

Most patients with hospital-acquired pneumonia are very ill, and they become colonized with a bacterium in their mouth and/or upper respiratory tract that then enters their lungs to cause infection.

The most common causes of hospital-acquired pneumonia are Pseudomonas aeruginosa and Staphylococcus aureus.

Risk factors

Although anyone can develop bacterial pneumonia, certain factors increase the risk.

According to the Cleveland Clinic, people who have a weakened immune system as a result of cancer, cancer treatment, or an organ transplant face an increased risk of bacterial pneumonia.

Smoking tobacco products and having a long-term lung condition, such as emphysema or chronic bronchitis COPD, increases the risk. Being over 65 years of age and having had recent surgery also puts people at a higher risk.

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A chest X-ray can help identify areas of inflammation.

Healthcare professionals can create a diagnosis of bacterial pneumonia after completing various diagnostic tests and performing a thorough history and physical exam. During a physical exam, the doctor will listen to the lungs to determine whether they sound dysfunctional.

In most cases, a doctor will conduct a chest X-ray to check for areas of inflammation and infiltrate in the lungs.

Additional tests may also support a pneumonia diagnosis, such as a chest CT scan and an arterial blood gas (ABG) sample. An ABG measures the amount of oxygen and carbon dioxide in the arterial blood, in addition to other things like pH and bicarbonate levels, and helps determine breathing efficiency and gas exchange.

The medical team might also perform a bronchoscopy to look into the lung airways and obtain a biopsy or a mucus sample. The operating doctor inserts a small tube with a tiny camera attached through the mouth into the lungs.

A person receives medication before a bronchoscopy to numb and relax the throat, and the doctor typically also gives intravenous sedating medication.

Treatment for bacterial pneumonia includes antibiotics, which target the specific type of bacterium causing the infection. A doctor might also prescribe medications to ease breathing.

Additional medications may include over-the-counter (OTC) drugs to ease aches and pains, as well as reducing fever.

Home care will often include rest and drinking plenty of fluids unless a doctor instructs otherwise. Be sure to finish a course of antibiotic therapy according to the doctor’s prescription, even if symptoms have improved.

Some people may require hospitalization for a severe case of bacterial pneumonia, especially for a person who needs supplemental oxygen, is experiencing dehydration, or requires breathing assistance with a mechanical ventilator.

People who develop complications, like sepsis, may also require additional treatments that involve admission into a hospital.

As a precaution, those who have an increased risk of complications may also benefit from admission to enable closer monitoring. These groups include people over 65 years or under 2 months of age.

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A person can receive a vaccine for pneumonia from the age of 2 months.

One of the best ways to prevent bacterial pneumonia is by preserving the strength of the immune system. Eating healthy foods, getting enough rest, and frequent hand-washing are good starting points.

Since bacterial pneumonia can develop as a complication of the flu, getting an annual flu shot may prevent pneumonia.

Two different pneumococcal vaccines are also available for reducing a person’s risk of developing bacterial pneumonia due to S. pneumoniae bacterium, the most common cause of bacterial pneumonia. These vaccines are the PCV13 and PPSV23, which protect against 13 and 23 strains of the pneumococcal bacterium respectively.

Doctors recommend that adults over 65 years of age have both types of vaccine. Children should receive a series of PCV13 vaccination starting at 2 months of age. Overall health status and age may affect the recommendation for pneumococcal vaccination.

Ultimately, a doctor will be able to determine which vaccine you may need and when to have them.

Recognizing bacterial pneumonia

In addition to bacteria, viruses and fungi can also cause pneumonia. Regardless of the cause, symptoms of pneumonia are often similar.

The similar symptoms in people with both viral and bacterial pneumonia can make determining the cause difficult.

According to the Cleveland Clinic, symptoms of bacterial pneumonia tend to be more severe than viral pneumonia and can come on suddenly. Symptoms of viral pneumonia tend to develop more slowly and are more similar to the flu at first.

One way to tell the difference between viral and bacterial pneumonia is a mucus sample, also called a sputum sample. A person coughs up a mucus sample, or a doctor obtains one from the lungs during a bronchoscopy.

A medical professional then analyzes it in the laboratory to determine the presence of any bacteria.

Supportive treatment for pneumonia, such as supplemental oxygen and fever-reducing medicine, is often the same regardless of the cause. The main difference in treatment is that antibiotics are for treating bacterial pneumonia but are ineffective for viral pneumonia.


Is bacterial pneumonia more dangerous than viral pneumonia.


Depending on immune system function, either type of pneumonia could be dangerous, especially in those with a weaker immune system.

For example, if a person is an older adult and has weaker immune system functioning, a viral infection, such as influenza, may develop into viral pneumonia, or it could lead to further weakening of the immune system, in which secondary bacterial pneumonia could occur.

A person in better overall health with a better functioning immune system has a lower risk of having pneumonia in general. However, is an individual has significant or worsening symptoms that could due to any type of pneumonia, visiting a physician is the best course of action for appropriate diagnosis and treatment.

Stacy Sampson, DO Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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