Salmonella enterica serotypes isolated for the first time in laying hens, and their susceptibility to antibiotics

In this study, a total of 323 drag swab samples were taken from laying hen fresh feces from 3 different provinces (Kırklareli, Edirne, and Tekirdağ), which are located in the European part of Türkiye. According to the ISO 6579: 2002 method, 17.3% of the samples were found positive for Salmonella. Obtained 56 Salmonella isolates were serotyped by slide agglutination using antisera according to Kauffmann White Le Minor Scheme. Sixteen serotypes of Salmonella were identified as S. Typhimurium (28.6%), S. Kentucky (17.9%), S. Abony (16.1%), S. Infantis (8.9%), S. Enteritidis (5.4%), S. Anatum (3.6%), S. Saintpaul (3.6%), S. Szentes (1.8%), S. Dibra (1.8%), S. Fallowfield (1.8%), S. Kimuenza (1.8%), S. Escanaba (1.8%), S. Nagoya (1.8%), S. Mbandaka (1.8%), S. Agona (1.8%), and Salmonella II 17: e, n, x, z15: 1,6 (1.8%). Isolations of S. Kimuenza, S. Escanaba, and S. Nagoya from laying hens are reported for the first time in Türkiye. The isolations of S. Dibra, S. Fallowfield, S. Szentes, and Salmonella II 17: e, n, x, z15: 1,6 from laying hens are the first report in the world. A total of 56 Salmonella isolates were tested for susceptibility to amoxicillin-clavulanic acid, cefepime, azithromycin, cefoxitin, and trimethoprim/sulfamethoxazole by the disk diffusion method. While 10% of S. Kentucky isolates were resistant to ofloxacin, and S. Kimuenza was only resistant to chloramphenicol.

The Efficacy of a Trivalent Inactivated Salmonella Vaccine Combined with the Live S. Gallinarum 9R Vaccine in Young Layers after Experimental Infections with S. Enteritidis, S. Typhimurium, and S. Infantis

Worldwide, poultry infections by Salmonella are the cause of significant economic losses, not only due to reduced production (due to fowl typhoid disease), but also considering the efforts and control measures that must be constantly applied, especially due to zoonotic serovars. Poultry is a common reservoir of Salmonella and its transmission into the food chain is a risk for humans. The vaccination of layers plays an important role in the overall efforts to prevent Salmonella infections. An inactivated trivalent vaccine was prepared with S. Enteritidis, S. Typhimurium, and S. Infantis strains. Infection trials were performed to evaluate the efficacy of three vaccination schedules using inactivated and live S. Gallinarum 9R vaccines. For this purpose, at week 5 of life, one subcutaneous dose of live S. Gallinarum 9R vaccine (1-5 × 107 CFU) was given to Groups 1 and 2. At weeks 8 and 11 of life, chickens were also vaccinated with one (Group 1) or two (Groups 2 and 3) intramuscular doses of the inactivated oil-adjuvant trivalent vaccine (1 × 108 CFU/dose of each antigen). Group 4 consisted of chickens that remained unvaccinated (control). At week 14 of life, the efficacy of the vaccination plans was evaluated in three separate inoculation trials with S. Enteritidis, S. Typhimurium, or S. Infantis. After vaccination with the inactivated vaccine, homologous antibody production was observed, and after challenge, a significant reduction in the faecal shedding, invasion, and colonization of S. Typhimurium and S. Infantis was achieved by all vaccination schedules, while the vaccination with at least one dose of the live S. Gallinarum 9R vaccine was necessary to obtain such a significant protection against S. Enteritidis infection.

The effect of volatile oil mixtures on the performance and ilio-caecal microflora of broiler chickens

The aim of this study was to investigate the individual and combined effects of rosemary, oregano and fennel volatile oil (FVO) supplementation on the performance and ilio-caecal bacteriological flora of broiler chickens. A total of 800 male Ross-308 broiler chickens were divided equally into 8 groups; each contained 100 chickens. The study included a control treatment (NC) with no dietary additives that was supplemented with oils according to the following 7 treatments: 200 mg α-tocopherol acetate/kg (PC), 100 mg oregano volatile oil (OVO)/kg, 100 mg rosemary volatile oil (RVO)/kg, 100 mg FVO/kg and an equal mixture of oregano+rosemary+fennel VO (100, 200, 400 mg/kg, VOM-1, VOM-2 and VOM-3, respectively). The experiment lasted for 6 weeks. At the end of the experiment, dietary supplementation with α-tocopherol, oregano, rosemary and FVO and two different volatile oil mixtures (VOMs) (VOM-2; VOM-3) significantly increased the body weights (BWs) of broilers at 7, 14 and 21 d of age compared to the negative control (NC) (-) and VOM-1 groups. At 0-42 d, birds fed on VOM-3 were considerably heavier and also gained more weight than NC (-) and VOM-1 groups. The blend of VOs at 400 mg/kg significantly increased Lactobacillus spp. in faeces. The blends of oregano, rosemary and FVOs (VOM-3) at 400 mg/kg concentration and also VOM-3 group exhibited stronger antibacterial activity against coliform bacteria compared to the NC (-) group. In conclusion, the blend of oregano, rosemary and fennel VOs at higher concentrations (400 mg/kg concentration) in diets can be used to stimulate the growth and can improve the intestinal microbial balance (including a reduction of coliform bacteria and an increase in Lactobacillus spp. counts) of broiler chickens.

Comparison of a real-time PCR method with a culture method for the detection of Salmonella enterica serotype enteritidis in naturally contaminated environmental samples from integrated poultry houses

Conventional culture methods have traditionally been considered the "gold standard" for the isolation and identification of foodborne bacterial pathogens. However, culture methods are labor-intensive and time-consuming. A Salmonella enterica serotype Enteritidis-specific real-time PCR assay that recently received interim approval by the National Poultry Improvement Plan for the detection of Salmonella Enteritidis was evaluated against a culture method that had also received interim National Poultry Improvement Plan approval for the analysis of environmental samples from integrated poultry houses. The method was validated with 422 field samples collected by either the boot sock or drag swab method. The samples were cultured by selective enrichment in tetrathionate broth followed by transfer onto a modified semisolid Rappaport-Vassiliadis medium and then plating onto brilliant green with novobiocin and xylose lysine brilliant Tergitol 4 plates. One-milliliter aliquots of the selective enrichment broths from each sample were collected for DNA extraction by the commercial PrepSEQ nucleic acid extraction assay and analysis by the Salmonella Enteritidis-specific real-time PCR assay. The real-time PCR assay detected no significant differences between the boot sock and drag swab samples. In contrast, the culture method detected a significantly higher number of positive samples from boot socks. The diagnostic sensitivity of the real-time PCR assay for the field samples was significantly higher than that of the culture method. The kappa value obtained was 0.46, indicating moderate agreement between the real-time PCR assay and the culture method. In addition, the real-time PCR method had a turnaround time of 2 days compared with 4 to 8 days for the culture method. The higher sensitivity as well as the reduction in time and labor makes this real-time PCR assay an excellent alternative to conventional culture methods for diagnostic purposes, surveillance, and research studies to improve food safety.