The four cases we have reported illustrate several interesting points. As was brought out by Coventry and his coworkers in their report of a case of Brucella suis infection of the hip in 1949, and as was further demonstrated in one of our cases, the results of Brucella cultures of aspirated fluid from a site of Brucella infection are many times reported as negative, while cultures of tissue taken from the same site give positive results. The results of the agglutination test for Brucella, when positive, are not significant enough to establish a diagnosis of localized brucellosis. We feel that the only certain way to make a diagnosis of brucellosis is by isolation of the organism; in patients with localized lesions, this is best done by bacteriological examination of the tissue removed at operation. Cultures of such tissue in our hands have given a more reliable basis than any other type of culture for making a positive diagnosis of brucellosis. This fact has already been emphasized32.
Lastly, we wish to stress the point that localized lesions do occur and represent a definite clinical entity. The most important factors leading to the diagnosis of brucellosis are: (1) a suspicion that such an infection is present, and (2) actual bacteriological isolation of the organism.