Nocardia



Nocardia is a genus that resembles mycobacteria. It is a grampositive to gramlabile rod and sometimes partially acid resistant microorganism. It has a specific wall structure. Morphologically they also resemble actinomycetes. The most important representatives are Nocardia asteroides, Nocardia caviae a Nocardia brasiliensis. They occur naturally in water and soil, from where they often enter the human body by inhalation. Inter-human transmission has not been demonstrated. In terms of immunity, cell-mediated immunity plays the greatest role.

Cultivation
Cultivation is carried out on Sabourad agar. Nocardia grow in white to orange rigid colonies. Sputum and pus are collected for microscopic examination. Biochemical tests are used to determine the exact species.

Diseases
Nocardiosis is a disease that resembles tuberculosis, this pulmonary form is most often caused by Nocardia asteroides. A serious complication is metastatic brain abscess. Mortality from this disease is reported to be up to 40%  . When the cutaneous form develops, which is caused by bacterial penetration through the injured skin, an actinomycetous mycetoma is formed – an infectious lesion that may resemble a tumor and in later stages it communicates with the surrounding area through fistulas. Previously, nocardiosis was of minor importance, but because of the spread of AIDS, these bacteria are the cause of frequent complications.

Therapy
Co-trimoxazol and tetracycline are indicated as suitable antibiotics for the treatment of nocardiosis; and resulting mycetomas are often treated surgically.