Detection of Virulence and ß-lactamase resistance genes of non-typhoidal Salmonella isolates from human and animal origin in Egypt "one health concern".

BACKGROUND: Non-typhoidal Salmonella (NTS) is a major foodborne zoonotic pathogen worldwide. In the current study, Various NTS strains were isolated from (cows, milk and dairy products in addition to humans) in New Valley and Assiut Governorate, Egypt. NTS were firstly serotyped and tested by antibiotic sensitivity test. Secondly, some virulence genes and Antibiotic resistance genes have been identified by using PCR. Finally, Phylogenesis was performed depending on the invA gene, for two S. typhimurium isolates (one of animal origin and the other of human origin for evaluating zoonotic potential). RESULTS: Out of 800 examined samples, the total number of isolates was 87 (10.88%), which were classified into 13 serotypes, with the most prevalent being S. Typhimurium and S. enteritidis. Both bovine and human isolates showed the highest resistance to clindamycin and streptomycin, with 90.80% of the tested isolates exhibiting MDR. The occurrence of the invA gene was 100%, while 72.22%, 30.56%, and 94.44% of the examined strains were positive for stn, spvC, and hilA genes, respectively. Additionally, blaOXA-2 was detected in 16.67% (6/ 36) of the tested isolates, while blaCMY-1 was detected in 30.56% (11of 36) of the tested isolates. Phylogenesis revealed a high degree of similarity between the two isolates. CONCLUSIONS: The high occurrence of MDR strains of NTS in both human and animal samples with high degree of genetic similarity, shows that cows, milk and milk product may be a valuable source of human infection with NTS and interfere with treatment procedures.

Genetic Correlation of Virulent Salmonella Serovars (Extended Spectrum ß-Lactamases) Isolated from Broiler Chickens and Human: A Public Health Concern.

This study aimed to detect the virulent Salmonella serovars (including ESBLs producing) isolated from broiler chickens and humans. Three hundred broilers and sixty human fecal samples were bacteriologically examined. Thirty (10%) and fourteen (23.4%) Salmonella isolates were recovered from broiler and human samples, respectively. The most predominant serovar was S. enteritidis and S. typhimurium. All Salmonella isolates were confirmed by conventional PCR-based invA and ompA genes. Multidrug resistant (MDR) isolates were screened for the detection of adrA and csgD biofilm-associated genes, which were found in all isolated serovars except one S. typhimurium and 2 S. infantis of chicken isolates that were devoid of the adrA gene. Moreover, MDR isolates were screened for detection of seven resistance genes including ESBLs and other classes of resistance genes. Chicken isolates harbored blaTEM, int1, blaCTX and qnrS genes as 100, 27.8, 11.1 and 11.1%, respectively, while all human isolates harbored blaTEM, int1 and int3 genes. The genetic correlations between virulent Salmonella serovars (including antimicrobial resistance) avian and human origins were compared. In conclusion, the high prevalence of virulent ESBL producing Salmonella serovars in broilers and humans with genetic correlations between them might be zoonotic and public health hazards.

Preparation and the assessed efficacy of oral baits for the vaccination of free-roaming dogs against rabies.

Background and Aim: Rabies is considered a highly fatal zoonotic disease and many deaths in humans have been associated with dog bites. This study was designed to prepare an oral anti-rabies vaccine in the form of baits to eliminate the disease in free-roaming dogs and subsequently protect humans from dog bites. Materials and Methods: The Evelyn Rokintniki Abelseth (ERA) rabies virus strain was propagated in baby hamster kidney cell cultures and adjusted to the recommended dose for application. Four forms of oral baits were employed with the rabies vaccine, which was evaluated for safety, acceptability, and potency in different dog groups. Enzyme-Linked Immunosorbent Assay (ELISA) and the serum neutralization test (SNT) were used to determine the protective rabies antibody titer in the sera of vaccinated dogs. Results: According to the results, a dose of 3 mL of the ERA strain, containing a viral titer of 107.6 TCID50/mL, induced a mean antibody titer of 25.6 by SNT, and the PI% was 75.7 by Block ELISA, providing a protective level of the rabies antibody in 100% of vaccinated dogs. All used baits were found to be safe, inducing no abnormal general post-vaccination signs (the signs are limited to mild fever, mild loss of appetite, and mild-to-moderate loss of energy for 24-36 h after vaccination). Conclusion: It was found that most of the accepted and highly potent bait types consisted of a mixture of wheat flour, vegetable oil, sodium alginate, corn starch, meat meal, cellulose gum, and water. This dog meal was covered with bran and edible wax to seal the bait cavity after inserting the vaccine sachet. This bait was able to induce a protective level of rabies antibodies in 100% of vaccinated dogs after receiving one bait/dog. Hence, such a bait could be recommended for use in the protection of free-roaming dogs and the elimination of the disease.

Effects of the Probiotic Candidate E. faecalis-1, the Poulvac E. coli Vaccine, and their Combination on Growth Performance, Caecal Microbial Composition, Immune Response, and Protection against E. coli O78 Challenge in Broiler Chickens.

The present study was performed on 180-day-old commercial Cobb chicks to assess the effects of the probiotic candidate Enterococcus faecalis-1, the Poulvac Escherichia coli vaccine, and their combination on growth parameters, intestinal microbial composition, immune response, and protection against challenge with the avian pathogen E. coli O78. The experimental groups were as follows: G1, basal diet; G2, basal diet and challenge with O78 at 28 days of growth; G3, basal diet, vaccination with Poulvac (1 and 15 days), and challenge with O78 at 28 days of growth; G4, basal diet, E. faecalis-1 supplementation for the first 3 days of growth, and challenge with O78 at 28 days of growth; G5, basal diet, E. faecalis-1 supplementation for the first 3 days of growth, vaccination with Poulvac (1 and 15 days), and challenge with O78 at 28 days of growth; G6, basal diet and E. faecalis-1 supplementation for the first 3 days of growth. The results showed that E. faecalis-1 in drinking water significantly improved the growth performance and immune response, increased the total Enterococcus counts, reduced the mortality, and decreased the visceral invasion by O78 in challenged broilers. While the effect of the Poulvac vaccine alone or with E. faecalis-1 was not significant compared with that of the E. faecalis-1 supplement, the vaccine improved the growth rate and decreased the mortality and visceral invasion by APEC O78 in challenged broilers. These results showed that E. faecalis-1 supplementation and routine vaccination with the Poulvac vaccine could improve the growth performance and immune response of broiler chickens and protect against challenge with APEC O78.