Lung infections can be bacterial, viral, fungal or parasitic and can range from minor to life threatening. As with other sources of infection, bacteria can cause inflammation in the lungs -- pneumonia -- or in the trachea and its branches -- bronchitis, although most cases of bronchitis tend to be viral (2, 3, 4). Bacteria can also spread and cause areas of tissue death after food or fluids have accidently made their way into the lungs (4). Treatment of bacterial lung infections will depend on the area of infection and how it was acquired (4)
According to a 2011 report from the Centers for Disease Control and Prevention, pneumonia is the 8th leading cause of death in America, sharing a spot with the flu (1). The most common cause in America adults is bacteria -- mainly Streptococcus pneumonia. A complication of pneumonia is empyema, where the lungs fill with pus. Empyema can also be brought on by complications of surgery, ruptured esophagus or physical injury (4). Although rare, bacterial bronchitis can occur after a viral respiratory infection has weakened the immune system, but is most likely to occur in the case of an outbreak (3, 4). When bits of food or fluid get sucked into the lungs in what is known as aspiration, areas of dying tissue, or abscesses, can develop after a few weeks (4).
Bacterial pneumonia is acquired in a community, hospital or congregate living setting, but can also occur due to autoimmune disease. The most common cause of community acquired pneumonia is streptococcus, although less common types can be responsible (2, 4). In a hospital, seriously ill patients can aspirate bacteria into their lungs, especially if they are using a machine to help them breathe. Pneumonia associated with health care settings affects people who live in nursing homes and similar environments, especially if they under go IV therapy, wound care or hospitalization (2, 4). Bacterial bronchitis accounts for 5 percent of cases and usually occurs in people with underlying health problems. As with pneumonia, the most common culprit of bacterial bronchitis is streptococcus (3, 4).
Symptoms of bacterial pneumonia are generally similar for all types and may include cough, fever, chest pain, gastrointestinal symptoms, trouble breathing and an overall ill feeling. In health care associated pneumonia, changes in mental status, appetite loss, incontinence, weakness, irritability and falling are common (2, 4). Initially, people with acute bacterial bronchitis feel tired and have a sore throat, runny nose, chills and a cough that is dry at first (3, 4). A slight fever can occur as opposed to the high temperatures seen with the flu (3, 4).
Diagnosis and Treatment
A trained medical professional will give a diagnosis of pneumonia after a medical history review, physical examination and X-ray and may need to test blood or sputum to see which bacteria is causing illness (2, 4). Doctors look for signs like increased heart rate, wheezing or crackles, abnormal breathing and other typical signs of pneumonia. Treatment depends on the setting in which pneumonia was acquired and usually includes antibiotics and support for difficulty breathing (2, 4). Bronchitis is diagnosed with physical examination and review of medical history, X-ray and throat sample (3, 4). Fever reducing medications are given as necessary and antibiotics are prescribed if bacteria is discovered or in the case of a known outbreak (3, 4)
Prevention and Risk Factors
Vaccines have been developed that can help prevent bacterial pneumonia. The pneumococcal vaccine can help protect against streptococcus-related pneumonia ( 2, 4, 5). The Haemophilus influenzae type b and influenza vaccines are important because they protect the immune system from being weakened by viruses that can pave the way for opportunistic bacterial infections (2, 4, 5). Bacterial bronchitis is difficult to prevent, but avoiding or quitting smoking, getting appropriate vaccinations, hand-washing and steering clear of those infected can reduce the risk of illness 3, 4, 6). People who are risk for pneumonia and bronchitis include smokers, the unvaccinated, those with immune deficiencies, children, the elderly, bedridden or paralyzed individuals, those with chronic respiratory infections and people taking certain medication (2, 3, 4, 5, 6).
Warnings and Precauitions
Bacteria that cause pneumonia and bronchitis spread through germs that travel through the air when an infected person coughs, sneezes or has direct contact with other people (4). It is best to avoid sick individuals when possible, practice thorough hand washing and follow vaccination recommendations from a medical doctor. Seek emergency medical attention in the case of persistent or increasing fever, rapid heart rate, sudden dizziness, mental confusion, new or intensifying chest pain, extreme shortness of breath and blue tinted lips or nails (6, 7). For children, the elderly and people with compromised immune systems call for emergency help -- better safe than sorry.
- Centers for Disease Control and Prevention: National Vital Statistics Reports
- Merck Manual: Overview of Pneumonia
- Merck Manual: Acute Bronchitis
- Infectious Diseases Society of America: American Thoracic Society Consensus Guidelines on the Management of Community-Acquired Pneumonia
- American Lung Association: Preventin Pneumonia
- American Lung Association: Managing and Preventing Acute Bronchitis
- University Health Service: Colds and Flu: Upper Respiratory Infections