The western immunoblotting technique in atypical situations of Rickettsia conorii infection. Presentation of 2 cases

BACKGROUND: During the last few years the application of Western immunoblotting in the study of human infection by Rickettsia conorii has led to the development of a new method of serologic diagnosis of the Mediterranean exanthematous fever. METHODS: The pattern of reactivity of serum samples sequentially obtained in the course of infection versus R. conorii antigens (Malish 7 strain) purified in discontinued density gradient and separated by SDS-PAGE was analyzed by Western immunoblotting. RESULTS: The presence of typical profiles of rickettsial infection similar to those observed in the common forms of presentation of the Mediterranean exanthematous fever was demonstrated in a case of accidental infection transmitted via aerosol and followed by an incomplete clinical picture after the early administration of specific antibiotic therapy and in a patient with signs and symptoms characteristic of Mediterranean exanthematous fever in whom the results of indirect immunofluorescence tests were repeatedly negative. CONCLUSIONS: Western immunoblotting may be a specially useful technique as a complementary procedure in the laboratory to guide in the diagnosis of Mediterranean exanthematous fever in special situations.