Question

What do the DFA results indicate about what might be causing this disease?

Answer 1

Sputum direct fluorescent antibody (DFA) is a lab test that looks for micro-organisms in lung secretions.

Abnormal results may be due to an infection such as:

• Legionnaire disease
• Pneumonia due to certain bacteria

Legionnaire disease :

Legionnaire disease is an infection of the lungs and airways. It is caused by Legionella bacteria.

Causes

The bacteria that cause Legionnaire disease have been found in water delivery systems. They can survive in the warm, moist air conditioning systems of large buildings, including hospitals.

Most cases are caused by the bacteria Legionella pneumophila. The rest of the cases are caused by other Legionella species.

Spread of the bacteria from person to person has not been proven.

Most infections occur in middle-aged or older people. In rare cases, children can get the infection. When they do, the disease is less severe.

Risk factors include:

• Alcohol use
• Cigarette smoking
• Chronic illnesses, such as kidney failure or diabetes
• Long-term (chronic) lung disease, such as COPD
• Long-term use of a breathing machine (ventilator)
• Medicines that suppress the immune system, including chemotherapy and steroid drugs
• Older age

Pneumonia is a breathing (respiratory) condition in which there is an infection of the lung.

This article covers community-acquired pneumonia (CAP). This type of pneumonia is found in people who have not recently been in the hospital or another health care facility such as a nursing home or rehab facility. Pneumonia that affects people in health care facilities, such as hospitals, is called hospital-acquired pneumonia.

Causes

Pneumonia is a common illness that affects millions of people each year in the United States. Germs called bacteria, viruses, and fungi may cause pneumonia. In adults, bacteria are the most common cause of pneumonia.

Ways you can get pneumonia include:

• Bacteria and viruses living in your nose, sinuses, or mouth may spread to your lungs.
• You may breathe some of these germs directly into your lungs.
• You breathe in (inhale) food, liquids, vomit, or fluids from the mouth into your lungs (aspiration pneumonia).
• 

Pneumonia can be caused by many types of germs.

• The most common type of bacteria is Streptococcus pneumoniae (pneumococcus).
• Atypical pneumonia, often called walking pneumonia, is caused by other bacteria.
• A fungus called Pneumocystis jiroveci can cause pneumonia in people whose immune system is not working well, especially people with advanced HIV infection.
• Viruses, such as the flu virus, are also a common cause of pneumonia.

Risk factors that increase your chance of getting pneumonia include:

• Chronic lung disease (COPD, bronchiectasis, cystic fibrosis)
• Cigarette smoking
• Dementia, stroke, brain injury, cerebral palsy, or other brain disorders
• Immune system problem (during cancer treatment, or due to HIV/AIDS, organ transplant, or other diseases)
• Other serious illnesses, such as heart disease, liver cirrhosis, or diabetes
• Recent surgery or trauma
• Surgery to treat cancer of the mouth, throat, or neck.