Brucellosis 2003 proceedings - PHIDIAS

Poster Session
60- DIAGNOSIS OF HUMAN AND ANIMAL BRUCELLOSIS USING EXTRACTS
OF BACTERIA PHYLOGENETICALLY RELATED TO Brucella.
M. V. Delpino 1 , J. C. Wallach 1,2 , C. A. Fossati 1 and P. C. Baldi 1 . (1) Instituto de Estudios de la
Inmunidad Humoral, Facultad de Farmacia y Bioquímica, CONICET, UBA, Argentina. (2) Servicio de
Brucelosis, Hospital F.J.Muñiz, Buenos Aires, Argentina.
Members of the genus Brucella are gram negative alpha-proteobacteria that
cause brucellosis, an infectious disease affecting livestock and humans. The
production of antigens for the serological diagnosis of brucellosis implies the handling
of live Brucella, which is a dangerous pathogen. We speculated that cytoplasmic
proteins from other alpha-proteobacteria (Agrobacterium sp, Sinorhizobium sp and
Ochrobactrum sp) would show cross-reactivity with Brucella antigens and could be
used to diagnose brucellosis in humans and animals. Proteins from A. tumefaciens,
S. meliloti and O. anthropi were obtained by French press disruption, followed by
ultracentrifugation and DNAse and RNAse digestion. Indirect ELISAs were designed
in which the plates were coated with the corresponding cytoplasmic proteins at 0.5
µg/well. Cut-off values were calculated as mean ± SD of specific optical densities
(sOD= OD with antigen – OD without antigen ) obtained with normal sera (humans, 20; sheep,
20; cows, 36; dogs, 34). These tests were used to assay sera from humans (n=32),
sheep (n=75), cows (n=59), and dogs (n=61) infected with different Brucella species.
These sera were all positive for antibodies against lipopolysaccharides and
cytoplasmatic proteins of Brucella sp by previously described ELISA systems. Canine
infection by B. canis was detected with high specificity (97,6% for Agrobacterium,
93,3% for Sinorhizobium, 100% for Ochrobactrum) and sensitivity (32% for
Agrobacterium, 77% for Sinorhizobium, 100% for Ochorbactrum) by all the ELISAs
tested, and it was possible to diagnose the disease shortly after the exposure to the
pathogen (15 days). In contrast, normal sera from humans, sheep, and cattle yielded
high sOD with all the antigens, which resulted in high cut-off values and,
consequently, in low sensitivities. For human sera, cut-off values were 2.550 for
Agrobacterium, 1.820 for Sinorhizobium, 1.500 for Ochrobactrum; for sheep, cut off
values were 1.821, 1.255, and 0.856, respectively; for cattle, cut off values were
0.822, 0.930, and 0.665, respectively. These results show that antibodies to
cytoplasmatic proteins from related proteobacteria have no diagnostic role in ovine,
bovine and human brucellosis. In contrast, they allow the specific and sensitive
diagnosis of canine brucellosis and the detection of the infection by B. canis shortly
after the exposure to the pathogen.
61- HIGH PREVALENCE OF Brucella pinnipediae IN TISSUES FROM
APPARENTLY HEALTHY GREENLAND SEA HOODED SEALS (Cystophora
cristata).
M. Tryland 1,2 , K. K. Sørensen 3 , and J. Godfroid 4 . (1) Department of Arctic Veterinary Medicine, The
Norwegian School of Veterinary Science, Tromsø, Norway. (2) Department of Microbiology and
Virology, University of Tromsø, Norway. (3) National Veterinary Institute, Regional Laboratory,
Tromsø, Norway. (4) Veterinary and Agrochemical Research Centre, Brussels, Belgium.
We have previously reported a high prevalence (35%) of anti-Brucella
antibodies in sera from hooded seals. The aim of the present study was to look
further into Brucella-infections in hooded seals by bacteriological and serological
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