Bacterial Pneumonia
Bacterial pneumonia is an infection in one or both lungs. The bacteria cause the lung's air sacs (alveoli) to become inflamed and engorged with...

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Bacterial pneumonia is an infection in one or both lungs. The bacteria cause the lung’s air sacs (alveoli) to become inflamed and engorged with pus, fluid, and cellular debris. This often impairs the body’s ability to exchange oxygen and carbon dioxide. If you have bacterial pneumonia you might experience breathlessness or pain as you struggle to take in oxygen.

Bacterial pneumonia can be mild or serious, even leading to respiratory failure or death. How you will be affected depends on the potency of the bacterial agent and your age, health, and immune status.

Early treatment of the infection with antibiotics may significantly reduce the danger of acute respiratory distress.

How You Can Catch Bacterial Pneumonia

Bacterial pneumonia is classified based on where you acquire it—outside or inside a hospital. An infection that occurs in a healthcare setting is usually more serious because you are already sick. Also, this type of infection is often caused by more dangerous bacteria.

Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) refers to an infection that is the result of exposure to pathogens outside of a healthcare setting. This is the most common type. You may be infected by respiratory droplets in coughs or sneezes or by skin-to-skin contact.

The bacteria that commonly cause CAP include:

  • Streptococcus pneumoniae: This is the leading cause of bacterial pneumonia. This bacterium lives in the noses and throats of healthy people. It can enter your lungs through inhalation, or it can travel to the bloodstream from a wound or infection site within the body. 
  • Haemophilus influenzae: This bacterium may live in your upper respiratory tract and does not cause harm or illness until opportunity strikes, such as after a viral infection or when immune function is impaired. It is the second most common cause of bacterial pneumonia. 
  • Klebsiella pneumoniae:It is found in the mouth, skin, and digestive tract. This bacterium is more prone to infect those with weakened immunity. 
  • Staphylococcus aureus: Infection from this bacterium occurs more frequently among intravenous drug abusers, patients with chronic illness, or young children with immature immune systems. Approximately 1 in 4 healthy individuals carries the staph germ. It usually lives on skin or within the pharynx or intestine. About 2 in 100 individuals carry an antibiotic-resistant strain of the bacterium known as methicillin-resistant Staphylococcus aureus (MRSA). MRSA occurs more commonly in medical settings but is becoming increasingly common within the general community. It is spread by the sharing of personal items or through contact sports such as rugby or wrestling.

Hospital-Acquired Pneumonia

You get hospital-acquired pneumonia (HAP) within two to three days of exposure to germs in an inpatient or outpatient healthcare facility. This type of pneumonia is often more resistant to antibiotics and more difficult to treat than CAP. Examples of the germs that give rise to HAP include MRSA (methicillin resistant staphylococcus aureus) and Pseudomonas aeruginosa.

Risk Factors for Developing Pneumonia

Those who are at higher risk for developing bacterial pneumonia include:

  • infants and children
  • adults over age 65
  • individuals who are ill or have impaired immunity
  • long-term users of immunosuppressant drugs
  • chronic obstructive pulmonary disease (COPD) patients who use inhaled corticosteroids for lengthy periods
  • smokers

Recognizing the Signs of Pneumonia

The most common symptoms of bacterial pneumonia are:

  • cough with yellow, green, or blood-tinged mucus
  • chest pain that worsens when coughing or breathing
  • sudden onset of chills
  • fever of 102 degrees or above (lower than 102 in older persons)
  • headache
  • muscle pain
  • breathlessness or rapid breathing
  • lethargy
  • moist, pale skin
  • confusion (especially among the elderly)
  • loss of appetite

Tests and Diagnosis

To diagnose bacterial pneumonia, your doctor will:

  • listen for abnormal chest sounds that indicate heavy mucus secretion
  • take a blood sample to get a white blood cell count. A high count usually indicates infection.
  • take blood and/or mucus samples to identify the infection-causing pathogen.
  • order chest X-rays to confirm the presence and extent of infection

How to Treat Pneumonia

Your doctor may prescribe the following medications:

  • an antibiotic that fights the specific bacterium causing your infection
  • a cough medicine to calm the cough and to help you expectorate sputum
  • fever medication to reduce your temperature

Avoiding the Spread of Pneumonia

The U.S. Centers for Disease Control and Prevention (CDC) recommends a pneumococcal polysaccharide vaccine (PPSV) for adults age 65 and above. The vaccine is also available for adults of any age who are at higher risk for pneumonia due to impaired health or immune status.

The CDC recommends a pneumococcal conjugate vaccine (PCV13) for infants and young children. It is usually given to infants in several doses during their first year. It may be given at other times depending on a child’s vaccine schedule and healthcare needs.

A bout of the flu can weaken individual immune response and can provide the perfect opportunity for bacteria to invade the lungs. An annual flu shot can protect adults against influenza and certain forms of bacterial pneumonia.

You can also minimize your chance of becoming ill with bacterial pneumonia if you keep fit by exercising, eating well, avoiding smoking, and getting adequate rest. Washing hands with soap or an alcohol sanitizer can kill the germs that cause bacterial pneumonia.

Written by: Cynthia Chase and Marijane Leonard
Edited by:
Medically Reviewed by: George Krucik, MD
Published: Aug 16, 2012
Published By: Healthline Networks, Inc.
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