ABSTRACT
Scleroma, the chronic specific granuloma of the nose and upper respiratory tract is endemic in Egypt and many other countries. The exact pathogenesis of the disease as regards the etiologic role of Klebsiella rhinoscleromatis is contradictory. This work investigated the effect of experimental intravenous injection of Klebsiella rhinoscleromatis bacilli in albino rats to demonstrate that the organism can fulfill Koch's postulates. Organisms were isolated from biopsy specimens taken form nasal lesions of ten patients in the granulomatous stage of scleroma. Specimens were subjected to bacteriological and histopathological examinations to confirm the diagnosis. One hundred micro of freshly prepared bacterial inoculum containing 10[8] CFU/ml was injected weekly in the tail vein of each of thirty albino rats and repeated for 5 consecutive weeks. Biopsy specimens were taken form sacrificed animals and subjected to bacteriological and histopathological examinations. Positive histopathological diagnosis of scleroma was reported in the nose of 66.7% of rats, the larynx of 46.7%, the lungs of 26.7% and liver of 20% of rats. Bacteriological techniques were successful in revealing Klebsiella rhinoscleromatis form the nose of 36.7% of rats, the larynx of 30% and the lungs of 20% of rats. Various techniques were carried out to demonstrate the organisms in tissue sections. Two histochemical stains were employed including silver and periodic acid Schiff [PAS] stains. Immunoperoxidase technique using Klebsiella capsular type 3 antiserum was Care applied It gave positive results in 66.7% or the 6 stained liver sections inspite of negative bacteriological cultures. The histiocytic nature of the Mikulicz cells was confirmed using alpha-1 antitrypsin, an immunohistochemical marker of histiocytes, and by studying the ultrastructural features of Mikulicz cells using the transmission electron microscope