Thirty-two isolates of Campylobacter fetus subsp venerealis were obtained from 1 bull and 4 heifers with experimentally induced infection. When whole-cell antigens of isolates were cross titrated with antisera to the infecting strain, isolates from 3 heifers had limited antigenic variation, whereas whole-cell antigens of isolates from 2 cattle (the bull and a heifer) differed serologically from those of the infecting strain. Changes were detected specifically in 6 heat-labile antigens. Of the 6 heat-labile factors evaluated, all were initially present on the infecting parent strain, but not on early isolates obtained from 4 of the 5 cattle. Restriction enzyme analysis revealed minor variation in the DNA fingerprints of isolates obtained from individual cattle, thus implying stability of the Campylobacter genome once persistent infection is established. Isolates with identical restriction enzyme patterns expressed different heat-labile antigens. Correlation could not be found between the DNA electrophoretic pattern and the expression of heat-labile antigens.

Sarcocystis cruzi, pregnant cows, plasma alpha-fetoprotein concentrations, cannot be used as diagnostic tool for fetal death

Campylobacter fetus é o agente etiológico da campilobacteriose genital bovina, uma doença sexualmente transmissível que está associada com perdas reprodutivas em bovinos. Campylobacter coloniza a vagina e o útero e então infecta as células epiteliais do endométrio. O objetivo deste trabalho foi desenvolver um modelo ex vivo para quantificar a adesão de Campylobacter às células-alvo naturais específicas; este é um passo fundamental para o estabelecimento da infecção e estudos acerca da adesão e citotoxicidade sobre as células do hospedeiro natural não estão disponíveis. Os ensaios foram realizados a través da semeadura de Campylobacter fetus venerealis em culturas celulares epiteliais vaginais e uterinas.Células HeLa foram utilizadas como controle.A aderência bacteriana foi confirmada por microscopia óptica e a determinação da porcentagem de bactérias aderidas foi realizada em lâminas tingidas imunoquimicamente. Os resultados são apresentados como porcentagem de células com Campylobacter aderente e como o número de bactérias por células. Em comparação com as células HeLa controle, a análise estatística revelou que as culturas primárias mostram uma maior porcentagem de células infectadas e uma menor variação dos parâmetros avaliados. Este modelo de cultura primária pode ser útil para estudos sobre citopatogenicidade e adesão de diferentes cepas de campo de Campylobacter fetus. | Campylobacter fetus is the etiological agent of bovine genital campylobacteriosis, a sexually transmitted disease which is associated with reproductive losses in bovines. Campylobacter colonizes the vagina and the uterus and then infects the epithelial cells of the endometrium. The objective of this work was to develop an ex vivo model to quantify the adhesion of Campylobacter to its natural specific target cells; this is a key step for the establishment of infection and studies regarding the adherence and cytotoxicity on the natural host cells are not available. The assays were carried out by seeding Campylobacter fetus venerealis on bovine vaginal and uterine epithelial cell cultures. HeLa cells were used as control. Bacterial adhesion was corroborated by optical microscopy and determination of the percentage of adherent bacteria was performed on immunochemically-stained slides. Results are presented as percentage of cells with adherent Campylobacter and as number of bacteria per cell. In comparison to the control HeLa cells, the statistical analysis revealed that primary cultures show a higher percentage of infected cells and a lower variation of the evaluated parameters. This primary culture model might be useful for studies on cytopathogenicity and adhesion of different field strains of Campylobacter fetus.