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Objective: To develop a fast and efficient method for measuring prevalence and gene expression of representatives from the three major groups of Treponema, most frequently identified in DD biopsies from cattle.

Endocarditis lesions from 117 slaughter pigs were examined pathologically and etiologically in addition to 90 control hearts with cardiac valves. Lesions were located on the valves; however, the lesions had extended to the walls in 21 cases (18%). Lesions predominated on the mitral valve (59%). A total of 28 cases, from which no growth was obtained or a contamination flora was grown, were screened by fluorescence in situ hybridization (FISH) for bacteria (general bacterial probe) and probes specific for Streptococcus suis and Erysipelothrix rhusiopathiae, respectively. Using FISH, an additional 10 cases of endocarditis due to S. suis and E. rhusiopathiae were disclosed. Within lesions, streptococci predominated (53%) followed by E. rhusiopathiae (30%). Distinct features of both the lesions and the shape and localization of bacterial colonies were related to streptococci and E. rhusiopathiae. The propensity for streptococci to be localized on more than 1 valve in single hearts may be because S. suis–infected pigs tend to have been infected for a longer period compared with E. rhusiopathiae. Mineralization of endocarditis lesions was significantly associated with infection by streptococci, and was seen in 71% of the cases, whereas it was present in only 28% of lesions caused by E. rhusiopathiae. In addition, areas with mineralization were significantly correlated to the presence of a granulomatous reaction. Granulomatous endocarditis is likely a result of a foreign body reaction due to dystrophic mineralization. Local proliferation of valvular endothelial cells, found in 9 hearts in the current study, may increase the risk of developing thrombosing endocarditis in pigs.

Background Sepsis caused by Staphylococcus aureus constitutes an important cause of morbidity and mortality in humans, and the incidence of this disease-entity is increasing. In this paper we describe the initial microbial dynamics and lesions in pigs experimentally infected with S. aureus, with the aim of mimicking human sepsis and pyemia. Methods The study was conducted in anaesthetized and intravenously inoculated pigs, and was based on bacteriological examination of blood and testing of blood for IL-6 and C-reactive protein. Following killing of the animals and necropsy bacteriological and histological examinations of different organs were performed 4, 5 or 6 h after inoculation. Results Clearance of bacteria from the blood was completed within the first 2 h in some of the pigs and the highest bacterial load was recorded in the lungs as compared to the spleen, liver and bones. This probably was a consequence of both the intravenous route of inoculation and the presence of pulmonary intravascular macrophages. Inoculation of bacteria induced formation of acute microabscesses in the lungs, spleen and liver, but not in the kidneys or bones. No generalized inflammatory response was recorded, i.e. IL-6 was not detected in the blood and C-reactive protein did not increase, probably because of the short time course of the study. Conclusion This study demonstrates the successful induction of acute pyemia (microabscesses), and forms a basis for future experiments that should include inoculation with strains of S. aureus isolated from man and an extension of the timeframe aiming at inducing sepsis, severe sepsis and septic shock.