Diarréia em bezerros da raça Nelore criados extensivamente: estudo clínico e etiológico Diarrhea in Nelore calves: Clinical and etiologic study

A diarréia é considerada uma das principais causas de morbidade e mortalidade de bezerros neonatos. Foram colhidas 100 amostras fecais diarréicas e 30 amostras não diarréicas (grupo controle), de bezerros Nelore com até nove semanas de idade com o objetivo de detectar os enteropatógenos Salmonella spp., Escherichia coli, rotavírus, coronavírus, Cryptosporidium spp. e ovos de helmintos. Enteropatógenos foram detectados em 79,0% das amostras diarréicas e em 70,0% das amostras não-diarréicas. No grupo de bezerros com diarréia, E. coli (69,0%) foi o agente mais freqüentemente isolado, seguido de Cryptosporidium spp. (30,0%), coronavírus (16,0%) e rotavírus (11,0%). No grupo controle, E. coli, Cryptosporidium spp. e coronavírus foram detectados, respectivamente, em 66,7%, 10,0% e 3,3% das amostras. Salmonella spp. e ovos de estrongilídeos não foram encontrados nos dois grupos avaliados. A fímbria K99 foi identificada exclusivamente nas linhagens de E. coli isoladas de bezerros com diarréia (5,8%). Entre os antimicrobianos avaliados "in vitro" a enrofloxacina, a norfloxacina e a gentamicina foram os mais efetivos. O peso dos bezerros aos 210 dias de idade não apresentou diferença significativa entre os animais com e sem diarréia.<br>Diarrhea is considered as one of the main causes of morbidity and mortality in neonates calves. Fecal samples from 100 diarrheic and 30 non-diarrheic (control group) Nelore calves less than 9 weeks old were collected for Salmonella spp., Escherichia coli, rotavirus, coronavirus, Cryptosporidium spp., and for helminth eggs investigation. Enteropathogens were detected in 79.0% diarrheic samples and 70.0% non-diarrheic samples. Among diarrheic calves, Escherichia coli (69.0%) was the most common agent found, following by Cryptosporidium spp. (30.0%), coronavirus (16.0%), and rotavirus (11.0%). In the control group, E. coli, Cryptosporidium spp. and coronavirus were detected in 66.7%, 10.0% and 3.3% of the samples, respectively. Salmonella spp. and strongylids were not found in any of the calves from either group. The K99 fimbrial only was detected in E. coli strains from diarrheic calves (5.8%). Enrofloxacin, norfloxacin, and gentamicin were the most effective among the antimicrobials tested. The weight of 210-day-old calves did not show statistic differences between diarrheic and non-diarrheic calves

Immunization of Mice with Lactobacillus casei Expressing a Beta-Intimin Fragment Reduces Intestinal Colonization by Citrobacter rodentium ▿ †

Enteropathogenic Escherichia coli (EPEC) is a common cause of diarrhea in children from developing countries. Intimate adhesion of the bacteria to intestinal cells occurs via binding of the adhesin intimin to the TIR receptor exposed on cell surfaces. Here, Lactobacillus casei expressing a fragment of β-intimin (L. casei-Intcv) was tested as mucosal vaccines in mice against intestinal colonization with the murine pathogen Citrobacter rodentium. Oral or sublingual immunization of C57BL/6 mice with L. casei-Intcv induced anti-Intcv IgA in feces but no IgG in sera. Conversely, anti-Intcv IgG was induced in the sera of mice after sublingual immunization with purified Intcv. All vaccines were able to decrease C. rodentium recovery from feces. However, this reduction was more evident and sustained over time in mice immunized with L. casei-Intcv by the sublingual route. These mice also displayed an increase in interleukin 6 (IL-6) and gamma interferon (IFN-γ) secretion by spleen cells 10 days after infection. Additionally, oral or sublingual immunization of C3H/HePas mice, which are highly susceptible to C. rodentium infection, with L. casei-Intcv induced anti-Intcv antibodies and significantly increased survival after challenge. Immunohistological analysis of colon sections revealed that C. rodentium was located in deep fractions of the tissue from C3H/HePas mice immunized with L. casei whereas superficial staining was observed in colon sections from mice immunized with L. casei-Intcv. The results indicate that vaccines composed of L. casei expressing intimin may represent a promising approach and that the C3H/HePas infection model with C. rodentium can be used to evaluate potential vaccines against EPEC