Gram negative aerobic bacteria associated with an acute colitis and diarrhea in horse farm and evaluation of the efficacy of salmonella newport autogenous bacterin

Field problem in a governmental horse farm accompanied with a fever, acute colitis and diarrhea was investigated. A total, 58 fecal samples, 7 samples obtained from horses suffering from acute colitis and diarrhea and 51 fecal samples from horses had mild diarrhea. Bacteriological examination of 7 samples revealed isolation of Salmonella Newport, Escherichia coli, Klebsiella oxytoca and Proteus species with an incidence of 85.7%, 42.9%, 28.6% and 14.3% respectively while examination of 51 fecal samples obtained from horses had mild diarrhea revealed isolation of E. coli, Pseudomonas aeruginosa, Klebsiella oxytoca, Citrobacter freundii, Proteus species Kiebsiella pneumoniae and Salmonella Newport with an incidence of 86.3%, 39.2%, 29.4%, 25.5%, 21.6%, 11.8% and 2%, respectively. Serological identification of Salmonella species and E. coli were carried out. Salmonella enterica serotype Newport was recovered from 6 out of 7 horses suffering of acute colitis and diarrhea while it could be isolated from a horse had mild diarrhea. Salmonella Newport was isolated from the colonic mucosa and mesenteric lymph node of 2 dead horse. No Salmonella species could be isolated from feed and water. Analysis of the questionnaires showed access to new arrival the source of Salmonella excretion on horse farm. An experimental approach to control spreading of S. Newport by using a prepared S. Newport autogenous bacterin was evaluated in mouse model. Immunogenicity and protection studies against S. Newport challenge were performed in Balb/C mice. Mice were immunized I/M and S/C with 2 doses of an autogenous bacterin. Antibody responses were determined by enzyme-Linked-immunosorbent assay [ELISA]. Also, non-specific immune responses including nitric oxide production [NO], catalase activity and hydrogen peroxide release [H[2]O[2]], have been measured. Immunization of mice with the autogenous bacterin resulted in a significant enhancement of humoral response following to vaccination and challenge as compared to control group. Additionally, this immunization succeeded in raising NO production, activating catalase and increase H[2]O[2] release. Increasing survival was noticed in immunized mice [80% and 66.7%] being declined in challenged non-immunized group [6.7%]. It was concluded that the prepared autogenous S. Newport bacterin could elaborate not only humoral immune responses but also host innate responses against S. Newport. However, more studies should be conducted under field condition to evaluate the efficacy of vaccine

Comparison of protection induced by corynebacterium pseudotuberculosis toxoid and BCG vaccines in lambs

A total of 460 sheep in 3 distinct age/sex groups were examined to determine the occurrence of caseous lymphadenitis in Beni Suef Governorate. The results confirmed that frequency increased with age but also revealed increases in extent of involvement and occurrence of visceral lesion, particularly in association with lesion in the body. An attempt was conducted to evaluate the immunogenic value of toxoid [prepared from C. pseudotuberculosis field isolate] and BCG used in sheep farms. Application of ELISA revealed slight increase in antibody response to toxoid and BCG vaccines prior to challenge, however, at week 7 [1 week post challenge] there was statistical significance elevation of antibody titre in group A vaccinated with toxoid over group B vaccinated with BCG [P < 0.05]. The capacity for induction of memory is a better indicator of vaccine performance and is most effectively assessed by challenge in the natural host. The protection rates post challenge were 71.4%, 42.9% and 14.3% for lambs immunized with toxoid, BCG and non vaccinated group respectively. Generally, the toxoid vaccine [prepared from field isolate] has been shown to confer high but not absolute degree of protection against caseous lymphadenitis and was more efficient than BCG. In sheep, it is likely that a short period of expression is insufficient to induce strong immune response in vivo

Comparison of PCR amplification of the FIM a gene and cultural method for detction of salmonellae in food and water

Bacteriological examination of local and imported feedstuff samples revealed that 11 out of 600 feedstuff samples harboured salmonellae with un incidence 1.8%. The highest incidence of isolation was in imported bone and meat meal [4%]. A polymerase chain reaction was performed by amplification fim A gene as specific method for detection of salmonella in feed and water. In order to obtain higher specificity, we have selected a series of primers internal to the fim A gene sequence. The concordance percent between conventional cultural method and PCR of feed and water were 96.6% and 100% respectively. This assay enable to detect 10 C.F.U. / 100 ml water and 10 C.F.U. / 25 g feedstuffs and it could detect only Salmonella strains. The detection of all position samples and the failure to amplify the fragment from non Salmonella strains confirm that the fim A gene contain sequences unique to Salmonella genus and demonstrate that this gene is suitable PCR target for detection of Salmonella bacteria. This rapid assay provides a sensitive and specific means of screening drinking water samples as well as feedstuff samples for the presence of Salmonella spp