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Salmonella enterica subsp. enterica serovar Abortusovis is a major agent of abortion of the sheep and is firmly established, although at low prevalence, in Sicily. This paper describes the application rDNA gene restriction pattern fingerprinting to investigate relatedness among 7 serovar Abortusovis strains isolated at the "Istituto Zooprofilattico Sperimentale" of Sicily and 29 isolates identified at the Southern Italy Centre of Enterobacteriaceae between 1981 and 1989. Although Abortusovis serovar has exhibited a remarkable degree of homogeneity, genomic DNA polymorphisms, that have emerged, suggest possible importation of bacterial clones from different geographic areas.

An ELISA assay was performed to detect antigens of Brucella melitensis directly in the blood of patients affected by Brucellosis. Disposable polystyrene microtiter plates were coated with rabbit immunoglobulins anti-Brucella melitensis antigens and then incubated with sera of Brucellosis patients and sera of not infected normal subjects as a control, to standardize the conditions of the different steps of the assay. The level of the blood-containing Brucella antigen bound to the plate was measured by addition of anti-Brucella melitensis antiserum conjugated with alkaline phosphatase followed by incubation with the specific enzyme substrate. Sera from 9 Brucellosis patients not undergoing therapy were tested by this ELISA assay, and all showed values significantly higher than the control. A pool of 96 sera from normal subjects not infected with Brucella melitensis was used as a negative control. In addition, a different group of 8 sera from patients with Brucellosis undergoing therapy were also analyzed, but no difference in the ELISA value was observed between the two groups with or without therapy. The ELISA assay described in this paper could be a reproducible, sensitive and suitable test to detect Brucella-antigens in the blood of Brucellosis patients and it could be used in addition to the more common methods for a more thorough diagnosis of Brucellosis.

A crude extract of Brucella melitensis was obtained by sonication, centrifugation and dialysis, and analyzed by quantitative immunoelectrophoresis. CIE analysis, using a high titer purified rabbit antibody anti-brucella fraction, showed that the Brucella melitensis extract contained at least 22 antigens that all moved towards the anode. The antigens of the crude extract able to interact with IgG of patients affected by brucellosis, were identified by means of CRIE using sheep 125I-anti human IgG. Fifteen sera of patients affected by brucellosis were analyzed by CRIE and three (Ag6, Ag12, Ag15) of the 22 antigens were able to bind specific human IgG to their corresponding immunoprecipitates. Ag6 was the only one present after one day of the CRIE plate exposure. After treatment of brucellosis patients with antibiotics for two weeks, the three antigens were still able to bind the specific IgG, after two months of treatment the antigens were reduced to two (Ag6, Ag15), while after ten months only one antigen (Ag6) was still able to bind specific human IgG. The brucellosis titer determined with common methods gave normal values after ten months of therapy. These results suggest that Ag6 is the most important antigen specific for human IgG. A preliminary determination of the molecular weight range of these antigens was carried out by a combination of size exclusion chromatography and CIE analysis. The Kav values were all above 66 kD.