Bacteriological, molecular and histopathological evaluation of four vaccines’ protective role against caseous lymphadenitis in sheep

The caseous lymphadenitis disease (CLA) due to Corynebacteriumpseudotuberculosis has worldwide distribution and indicates high prevalence in different countries. The bacterium has many pathogenicity factors; firstly, “phospholipase D”, an exotoxin virulence factor that enhances vascular permeability and facilitates bacterial transmission causing endothelial cell damage. The bacterium's exterior lipid cover is the second pathogenicity factor. This protects it from hydrolytic enzymes found in the phagocytes of the host, where the bacteria proliferate and then release after rupturing.  Bacterial proliferation causes CLA abscesses, which are followed by attraction and the formation of an inflammatory response, which increases lymph flow and vascular permeability. The purpose of this study was to look atpostmortem findings, bacterial cultures, and histology of vaccinated sheep to see how well they were protected. On 15 male local sheep bread, four prepared vaccinations against C. pseudotuberculosis biotype 1 were tested. The animals were divided into 5 groups; four of various vaccines used and the fifthwere kept non-vaccinated. A live virulent strain of C. pseudotuberculosis was given to each group. Unvaccinated animals displayed CLA symptoms similar to those seen in spontaneously sick animals.&nbsp

Advanced molecular characterization of enteropathogenic Escherichia coli isolated from diarrheic camel neonates in Egypt

Background and Aim: Camels are important livestock in Egypt on cultural and economic bases, but studies of etiological agents of camelid diseases are limited. The enteropathogen Escherichia coli is a cause of broad spectrum gastrointestinal infections among humans and animals, especially in developing countries. Severe infections can lead to death. The current study aimed to identify pathogenic E. coli strains that cause diarrhea in camel calves and characterize their virulence and drug resistance at a molecular level. Materials and Methods: Seventy fecal samples were collected from diarrheic neonatal camel calves in Giza Governorate during 2018-2019. Samples were cultured on a selective medium for E. coli, and positive colonies were confirmed biochemically, serotyped, and tested for antibiotic susceptibility. E. coli isolates were further confirmed through detection of the housekeeping gene, yaiO, and examined for the presence of virulence genes; traT and fimH and for genes responsible for antibiotic resistance, ampC, aadB, and mphA. The isolates in the important isolated serotype, E. coli O26, were examined for toxigenic genes and sequenced. Results: The bacteriological and biochemical examination identified 12 E. coli isolates from 70 fecal samples (17.1%). Serotyping of these isolates showed four types: O26, four isolates, 33.3%; O103, O111, three isolates each, 25%; and O45, two isolates, 16.7%. The isolates showed resistance to vancomycin (75%) and ampicillin (66.6%), but were highly susceptible to ciprofloxacin, norfloxacin, and tetracycline (100%). The structural gene, yaiO (115 bp), was amplified from all 12 E. coli isolates and traT and fimH genes were amplified from 10 and 8 isolates, respectively. Antibiotic resistance genes, ampC, mphA, and aadB, were harbored in 9 (75%), 8 (66.6%), and 5 (41.7%), respectively. Seven isolates (58.3%) were MDR. Real-time-polymerase chain reaction of the O26 isolates identified one isolate harboring vt1, two with vt2, and one isolate with neither gene. Sequencing of the isolates revealed similarities to E. coli O157 strains. Conclusion: Camels and other livestock suffer various diseases, including diarrhea often caused by microbial pathogens. Enteropathogenic E. coli serotypes were isolated from diarrheic neonatal camel calves. These isolates exhibited virulence and multiple drug resistance genes

Antigenic evaluation of extracted fimbrial protein obtained from pathogenic Escherichia coli isolated from diarrheic camel neonates

Enteropathogenic Escherichia coli (EPEC) were considered prime reason of diarrhea among neonatal livestock animals in developing countries and could be of public health importance via contaminated milk and meat.  Continual attempts were conducted to combat this illness using various antigenic determinants. This study was performed on four E. coli serotypes O26, O45, O103 and O111, which were previously recovered from diarrheic camel calves in Giza, Egypt. Extraction of fimbrial proteins was carried out through dialysis then evaluation of their immunogenic activity was preceded. SDS-PAGE electrophoresis was performed on crude extracted fimbrial proteins and revealed single band for each isolate ranged from 22 to 33kDa. Immunobloting was implemented on the extracted crude fimbrial proteins against E.coli O26 antisera formerly prepared in rabbit.These findings suggested that the fimbrial proteins are of immunogenicity importance and can serve as a protective passive vaccine antigen in prevention of diarrhea caused by EPEC and ETEC infection in camel calves