Most people have suffered from different forms of pneumonia in their lifetime. A threatening kind of pneumonia infection results in the development of Legionnaires disease. The disease is caused due to infection by the air-borne bacteria Legionella. It is a pathogenic bacteria that affects the lower regions of the human respiratory tract. Legionella is also found to be instrumental in the development of Pontiac fever, marked by symptoms related to flu. Both Pontiac fever and Legionnaires disease are together called Legionellosis. Legionella testing is generally performed to detect the bacterial presence or its antigens. Let us look into the details of such tests below:-
Why is the test performed?
Although Legionella infection is associated with pneumonia, there are other kinds of pneumonia infections that take place in a human being. Many of these infections are not threatening and can be treated with medications. However, legionella infection requires hospitalization at times and has shown high mortality rates. Therefore, proper diagnosis and antibiotic treatment are necessary for such an infection.
What are the initial tests performed to detect the presence of Legionella?
The first step in the diagnosis of Legionellosis is the identification of the Legionella antigen in the urine of infected patients. Adults are more affected by bacteria. Although such tests are performed rapidly and can produce the results within hours, it can detect only serogroup 1 antigens’ presence. Therefore a negative result from the tests does not confer the absence of Legionella in the patient’s body.
Legionella culture analysis
In this test, special nutrient-rich media is allowed to come in contact with sputum collected from patients. These nutrients specifically allow Legionella to grow on the media. The test takes 2-3 days to be completed and is considered the best test for analyzing the bacteria’s presence in the sputum. Moreover, the rapid amplification of bacterial culture will enable the detection of its presence.
Direct Fluorescent Antibody Staining
The Legionella antigen can be detected by direct fluorescent staining by antibodies. This is a rapid procedure and can take a maximum of 2-4 hours to complete. Again, the drawback of antibody testing also stands true for this test, i.e., a negative test result might also occur due to obscurement of the bacterial antigens. A rapid Polymerase Chain Reaction test is better in this approach.
Legionella species are found in the natural world. It prefers a warm, moist climate and can grow in stagnant water. Therefore, legionella culture often develops in several plumbing systems. If you feel that your family members are showing Legionellosis symptoms, conduct a legionella test now.