Browsing by Author "Elsner, C."

Invasive zygomycoses (syn. mucormycoses) are rather rare but life-threatening diseases which often take a peracute course. Particularly endangered are diabetics and patients suffering from siderophilia. Zygomycosis is regularly complicated by thrombosis and subsequent necrosis. Usually it evolves from sinusitis in a rhinocerebral form. With the use of a clinical isolate (Rhizopus microsporus) and sera of the same female survivor, we investigated possible sources of the typical blood clotting. The results suggest that coagulation is probably initiated in a bimodal manner by an extracellular serine proteinase of the fungus and by elastase from the patients' leukocytes. The former causes a partial hydrolysis of fibrinogen, while the latter activates coagulation factor XIII (fibrin stabilizing factor). Both proteinases were present in the patient at the site of infection, and in vitro they jointly bring about regular clotting of fibrinogen.

Activation of blood coagulation to a varying extent affect the course of domestic invasive mycoses. Upon invasion of blood vessels by Candida or aspergilli, occasionally thrombi are formed, which may cause septic embolism. In the course of mucormycosis (syn. zygomycosis) thrombotic occlusion of afflicted blood vessels and subsequent necrosis of dependent tissue regularly occurs. Coagulation during candidosis or aspergillosis may be triggered by secreted aspartic proteinases which are able to activate factor X as has been shown previously [1, 2]. During mucormycosis, severe blood coagulation apparently is due to paracoagulation of fibrinogen which is triggered by low concentrations of extracellular fungal subtilisin-like proteinase (Arp). The enzyme is also able to inactivate the major inhibitor 4 blood coagulation (antithrombin III). Recent findings on the action of Arp are discussed.