다양한 Salmonella 혈청형의 증식을 억제하는 신규 박테리오파지 C-STyP21의 분리, 특성 분석 및 계통학적 분류 = Isolation, Characterization, and Phylogenetic Classification of a Novel Bacteriophage C-STyP21 Inhibiting the Growth of Diverse Salmonella Serovars

다국어 초록 (Multilingual Abstract)

Salmonella is a food poisoning bacterium that causes typhoid and non-typhoid diseases in humans and animals. In recent years, the number of cases of damage caused by various Salmonella serotypes is increasing, anrse due to the emergence of resistant bacteria to antibiotics used for treatment. Therefore, research on alternatives that can replace antibiotics is needed, and recently, it has begun to attract attention as an antibiotic alternative in that bacteriophage is high host specificity, it is possible to suppress the growth of harmful bacteria without affecting the normal flora, and it is easier to find new products than antibiotics.
In this study, we aimed to isolate phages that inhibit various Salmonella serotypes, analyze the characterization of the phages, and proceed with systematic classification.
Using Salmonella enterica serovar Typhimurium as the host strain in Chapter Ⅰ, novel phage C-STyP21 was isolated from samples of Gimje livestock manure treatment facility and confirmed that it is possible to inhibit various serotypes (Salmonella Enteritidis, Typhimurium, Thompson, Heidelberg, Infantis). In addition, genomic analysis confirmed that C-STyP21 has no genes that may be problematic when applied to food production, and it is likely to be new species.
characterization analysis was conducted with phage C-StyP21 previously isolated from Chapter Ⅱ. characterization analysis identified various life cycle-related parameters (adsorption rate, late period, burst size, etc.), evaluated stability and stress resistance under various processing and applied environmental conditions (temperature, pH, bail salt), and further tested the biological control efficacy of phages in complex food matrices such as egg yolk and milk to confirm their ability to inhibit Salmonella growth under realistic food processing conditions. Collectively, these results show the potential of C-StyP21 with a wide range of hosts newly isolated and as a biological control agent to mitigate Salmonella contamination in various industries, including food.

목차 (Table of Contents)

• Chapter Ⅰ. Salmonella multi-serovar 감염 박테리오파지 C-STyP21의 분리, 동정 및 새로운 species 가능성 1
• 1. 서 론 1
• 2. 재료 및 방법 4
• 2.1. Bacterial strains and culture conditions 4
• 2.2 Phage isolation 4
• 2.3. Host Range Determination 5
• 2.4. Polyethylene glycol (PEG) precipitation and CsCl gradient ultracentrifugation 5
• 2.5. Transmission electron microscopy (TEM) 6
• 2.6. Phage DNA extraction and whole genome sequencing 6
• 2.7. Bioinformatics analysis 7
• 3. 결 과 10
• 3.1. Isolation and host range analysis of Salmonella phage C-STyP21 10
• 3.2. TEM analysis of phage C-STyP21 13
• 3.3. Complete genome sequence analysis of C-STyP21 15
• 3.4. Classification of C-STyP21 27
• 3.5. Comparative analysis of tail length tape measure protein genus of phage C-STyP21 45
• 4. 고 찰 47
• Chapter Ⅱ. C-STyP21의 특성 분석 및 Salmonella Enteritidis 증식 억제를 위한 식품 적용 53
• 1. 서 론 53
• 2. 재료 및 방법 55
• 2.1. C-STyP21 propagation using various Salmonella serovars 55
• 2.2. Efficiency of plating (EOP) assay for C-STyP21 propagated in various serovars 55
• 2.3. Phage stability test assays 56
• 2.4. Adsorption study 57
• 2.5. One-step growth curve 58
• 2.6. Growth inhibition of Salmonella in liquid culture 58
• 2.7. Food application of C-STyP21 59
• 3. 결과 60
• 3.1. Plaque morphology analysis of phage C-STyP21 propagated in various serovars 60
• 3.2. Efficiency of plating (EOP) assay for phage C-STyP21 propagated in various serovars 67
• 3.3. Phage stability test assays 74
• 3.3.1. 저장 온도에 따른 C-STyP21 안정성 74
• 3.3.2. 고온 안정성 74
• 3.3.3 pH 안정성 75
• 3.3.4. Bile slat 안정성 75
• 3.4. Adsorption study and one step growth curve 78
• 3.5. Growth Inhibition of Salmonella in liquid culture (method 1) 80
• 3.6. Growth Inhibition of Salmonella in liquid culture (method 2) 84
• 3.7. Food application of C-STyP21 88
• 4. 고찰 90
• 참고문헌 96