ASPARAGINE BROTH

Description

Histoplasma capsulatum, a dimorphic fungus causes histoplasmosis, a systemic fungal disease. H. capsulatum is an obligate intracellular organism residing in macrophages of the reticuloendothelial system. Of current concern is the increased incidence of histoplasmosis in patients with AIDS. Coccidiodes immitis, the causative agent of coccidioidomycosis (Valley fever) is endemic in hot regions with dry climate and alkaline soil. Patients with AIDS are at a risk of developing coccidioidomycosis. Asparagine Broth is a chemically defined medium used for the preparation of Coccidioidin and Histoplasmin antigens. Histoplasma capsulatum or Coccidioides immitis are cultured in this medium for 1-3 months at 37?C till the static phase is obtained. At this stage, cells are autolyzed and a mixture of antigen haptens is prepared. Cell free filtrate from this medium is sterilized by filtration and used as the antigen. Preparation, standardization and administration of histoplasmin and the interpretation of delayed cutaneous hypersensitivity tests are identical to those for Coccidioidin.