Differentiation between serological responses to Brucella suis and Yersinia enterocolitica serotype O[ratio ]9 after natural or experimental infection in pigs

Abstract

False-positive serological reactions (FPSR) due to infections with Yersinia enterocolitica serotype Oratio9 (YeOratio9) are a problem in tests for brucellosis. In the present study, FPSR in classical and novel tests for brucellosis following experimental infections of pigs with YeOratio9 were compared with responses of B. suis biovar 2-inoculated pigs. FPSR were limited to 2-9 weeks post-YeOratio9 inoculation, while B. suis-infected pigs were test-positive throughout the 21-week period of investigation. Although YeOratio9-inoculated pigs exhibited FPSR in Brucella tests for a limited period of time, the serological responses in a YeOratio9-purified O-antigen indirect ELISA did not decrease accordingly. Analysis of available cross-sectional serum samples from pig herds naturally infected with YeOratio9 or B. suis biovar 2 confirmed that the observed difference in the duration of the serological responses between the two infections could be used to discriminate between herds infected with B. suis biovar 2 and YeOratio9.

Genotypic virulence markers of Yersinia enterocolitica O:9 isolated from pigs and wild boars serologically positive and negative for brucellosis

“…In our study, none of the isolates was ystB-positive. This result is similar to findings of other authors, who found that ail+ and ystA+ positive Y. enterocolitica strains are almost always ystB-negative (9,20).…”

“…One of the most important problems which should be always taken into account is the possibility of cross reactions between Brucella sp. and Y. enterocolitica O:9, which are difficult to distinguish from specific anti-Brucella reactions (6,9,14,16,20,23). The study of Szulowski et al (19) presents that each year, in Poland, a very limited number of cattle is classified as positive for brucellosis and slaughtered, but Brucella sp.…”

The porcine brucellosis – evidence of the role of Yersinia enterocolitica O:9 in occurrence of false positive serological reactions

“…Taking into account the data from the literature and our current and previous results we conclude that false positive serological reactions in porcine brucellosis serology are not unusual (Jungersen et al 2006, OIE Manual 2012 and clear guidelines for dealing with such cases should be created.…”

“…Detection of Y. enterocolitica O:9 in the herd with a high degree of probability confirms the reason of false positive reactions for brucellosis. Determining the presence of other serotypes of Y. enterocolitica in the herd, beside serotype O:9, is not surprising as there are no biological differences between the serotypes and their different distribution in the herd is possible (Jungersen et al 2006). Implementation of bacteriological examination for the presence of Y. enterocolitica O:9 and isolation of this bacteria provides very important information enabling proper interpretation of the results.…”

Soroprevalência de pseudorraiva, peste suína clássica e brucelose em suínos do estado do Piauí

“…Zootec., v.65, n.5, p.1321-1328, 2013 (Organización..., 1986), não é recomendado para áreas de baixa prevalência (Motta et al, 2010), uma vez que apresenta alta sensibilidade e baixa especificidade, podendo ocorrer reações cruzadas com Yersinia enterocolitica e Brucella spp. (Jungersen et al, 2006). Na região Nordeste, resultados semelhantes foram obtidos em estudo conduzido em granjas de suínos na região metropolitana de Recife, onde apenas 2,4% dos animais foram positivos ao 2-ME (Ribeiro et al, 2000).…”