Community-Acquired Pneumonia

    Community-Acquired Pneumonia

    Community-acquired refers to the fact that these types of pneumonia are usually spread from person to person within a community. It is not acquired from hospitals or healthcare facilities. There are three main types of community-acquired pneumonia: viral, bacterial or fungal.

    1. Viral Pneumonia

    In viral pneumonia, a virus invades the lungs causing them to swell and block the flow of oxygen. Viruses are the cause of the majority of cases of childhood pneumonia. According to the American College of Chest Physicians, viral pneumonia used to be a disease that was found only in young children and people over 65 years of age (Matsuoka & Eneloq, 2010). It is now common among all age groups. Nevertheless, children are considered high-risk cases because their bodies are more susceptible to infection.

    There are a number of viruses that can lead to viral pneumonia including:

    • Adenoviruses
    • Chickenpox
    • Influenza Virus
    • Respiratory Syncytial Virus

    Viruses usually spread from person to person within a community. Coughing, sneezing, or touching a surface that has been contaminated by another infected person is the most common way to catch a virus that causes viral pneumonia.

    Most cases of viral pneumonia clear up within three weeks. However, viral pneumonia can range from mild to severe, and can be complicated by secondary bacterial infection.

    2. Bacterial Pneumonia

    Bacterial pneumonia is caused by any number of bacteria1,2. Bacteria typically enter the lung with inhalation, although they can reach the lung through the bloodstream if other parts of the body are infected. Bacteria often travel from the lung into the blood stream and can result in serious illness, such as septic shock, in which there is low blood pressure leading to damage in multiple organs of the body, including the brain, kidney and heart. They can also travel to the areas between the lungs and the chest wall, called the pleural cavity, causing fluid to accumulate.

    Bacterial pneumonia can be caused by the following:

    Strptococcus pneumoniae is the most common bacterial cause of pneumonia in all age groups except newborn infants1, 2. Streptococcus pneumoniae or pneumococcus is a Gram-positive bacterium that often lives in the throat of people who do not have pneumonia.

    Pneumococcal disease attacks different parts of the body:

    • Meningitis, an infection of the lining of the brain and spinal cord resulting in brain damage and even death.
    • Acute Otitis Media, an infection of the middle ear leading to deafness.
    • Bacteraemia, an infection in the bloodstream causing life-threatening conditions.
    • Pneumonia, an infection of the lung causing chest pains and difficulty in breathing.

    Gram-Negative Bacteria

    Gram-negative bacteria are seen less frequently: Haemophilus influenzae , Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa , Bordetella pertussis, and Moraxella catarrhalis are the more common ones. These bacteria can also cause severe disease if not properly treated.

    Atypical Bacteria

    ‘Atypical’ bacteria are Coxiella burnetii, Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila3. Many people wrongly believe they are called ‘atypical’ because they are uncommon and/or do not respond to common antibiotics and/or cause atypical symptoms. In reality, they are ‘atypical’ because they do not gram stain as well as gram-negative and gram-positive organisms3.

    Diagnosing Pneumonia

    Although the chest x-ray may be able to show pneumonia, it cannot tell if the cause is a virus or bacteria4. Blood investigations may be able to elucidate the probable cause and blood taken for culture may even be able to identify the bacteria concerned4. Other indirect tests are measuring antibodies against certain bacteria (like Mycoplasma) and urine for antigen detection (for pneumococcus antigen)4. Viral pneumonias need symptomatic treatment while bacterial pneumonias need appropriate antibiotics.

    Preventing Viral & Bacterial Pneumonia

    Fortunately, you can protect your child against viral & bacterial pneumonia through vaccination2. The pneumococcal conjugate vaccine protects against pneumococcal infections, which mostly strikes children under age of 5 and can lead to some of the worse childhood diseases 1,2. It is recommended for infants and young children as early as 2 months2. The number of doses taken by a child is dependent on the age. The vaccine is available at all private hospitals and clinics.

    The Haemophilus influenzae type b (Hib) vaccination is also essential. This is provided to all children in Malaysia under the National Immunisation Programme.

    Also consult your doctor on other additional vaccines available to prevent pneumonia in your child today such as vaccination against measles, pertussis, influenza, chickenpox, and so forth.


    1. World Health Organisation (WHO) November 13 2013 Pneumonia Fact Sheet available online ( Accessed on 3 November 2014
    2. Centers for Disease Control & Prevention (CDC) Pneumonia can be prevented – vaccines can help. Available online ( Accessed on 3 November 2014
    3. American Academy of Family Physicians (AAFP) Atypical Pathogens and Challenges in Community-Acquired Pneumonia 2014 Available online ( Accessed on 3 November 2014
    4. Academy of Medicine of Malaysia & Malaysian Paediatric Association Guideline on Pneumonia and Respiratory Tract Infections in Children 2001 Available online ( Accessed on 3 November 2014