Nocardia culture is carried out to establish the diagnosis of Nocardiosis.
The sample for the test comprises of pus, aspirate, cerebrospinal fluid, respiratory specimen, or tissue. If the sample is a fluid or an aspirate it needs to be transferred to a sterile container after collection. If it is a tissue, it has to be kept on a gauze moistened with sterile saline, inside a sterile container, and transported to the lab.
The sample taken from a patient may be grown on a petri plate containing bacterial, mycobacterial or fungal media.
Colonies appear within 4 days of inoculation but it may take upto 2-3 weeks if the patient is being treated with antibiotics.Physiology :
Nocardia species are a group of aerobic, gram variable, filamentous bacteria which are relatively slow- growing and variably acid fast. They appear beaded, comprising of alternating gram positive and gram negative segments along the filament. The presence of filaments make them act like fungi, despite being true bacteria
Some species of Nocardia are non-pathogenic, while others cause the condition ‘Nocardiosis,’ which is a slow- progressing pneumonia with symptoms such as cough
and shortness of breath
. The route of infection is either through inhalation or through the skin.
Human infection of Nocardia is seen most frequently in patients whose immune systems are suppressed by HIV infection, lymphoreticular malignancy or chemotherapy.Normal Range :
No nocardia sp isolatedInterpretation : Normal
No Nocardia species can be seen on the culture plates.
Nocardia colonies appear mold-like and have a characteristic mildew odor, indicating Nocardia infectionSample :
pus, tissue, cerebrospinal fluid or other body fluid, aspirate, sputum.Test Method :
Aerobic culture on blood agar and Lowenstein Jensen media with no antibiotics.Infections may be acute, subacute, or chronic and they may be disseminated or localized to cutaneous sites or the respiratory tract.Related Tests :
Acid fast stain, Actinomyces culture, Sputum culture.