Abstract：
Staphylococcus aureus, a major foodborne pathogen, is frequently detected in fresh produce. It often causes food poisoning accompanied by abdominal pain, diarrhea, and vomiting. Additionally, the abuse of antibiotics to control S. aureus has resulted in the emergence of antibiotics-resistant bacteria, such as methicillin resistant S. aureus. Therefore, bacteriophage, a natural antimicrobial agent, has been suggested as an alternative to antibiotics. In this study, a lytic phage SSP49 that specifically infects S. aureus was isolated from a sewage sample, and its morphological, biological, and genetic characteristics were determined. We found that phage SSP49 belongs to the Straboviridae family (Caudoviricetes class) and maintained host growth inhibition for 30 h in vitro. In addition, it showed high host specificity and a broad host range against various S. aureus strains. Receptor analysis revealed that phage SSP49 utilized cell wall teichoic acid as a host receptor. Whole genome sequencing revealed that the genome size of SSP49 was 137,283 bp and it contained 191 open reading frames. The genome of phage SSP49 did not contain genes related to lysogen formation, bacterial toxicity, and antibiotic resistance, suggesting its safety in food application. The activity of phage SSP49 was considerably stable under various high temperature and pH conditions. Furthermore, phage SSP49 effectively inhibited S. aureus growth on baby spinach leaves both at 4 °C and 25 °C while maintaining the numbers of active phage during treatments (reductions of 1.2 and 2.1 log CFU/cm2, respectively). Thus, this study demonstrated the potential of phage SSP49 as an alternative natural biocontrol agent against S. aureus contamination in fresh produce.
摘要：
金黄色葡萄球菌,一种主要的食源性病原体，经常在新鲜农产品中检测到。常引起食物中毒并伴有腹痛,腹泻,和呕吐。此外,滥用抗生素来控制金黄色葡萄球菌导致了抗生素抗性细菌的出现，如耐甲氧西林金黄色葡萄球菌。因此,噬菌体,一种天然抗菌剂，已被建议作为抗生素的替代品。在这项研究中,从污水样品中分离出特异性感染金黄色葡萄球菌的裂解噬菌体SSP49，和它的形态，生物，并确定了遗传特征。我们发现噬菌体SSP49属于Straboviridae家族（Caudoviricetes类），并在体外保持宿主生长抑制30小时。此外,它对各种金黄色葡萄球菌菌株显示出高宿主特异性和宽宿主范围。受体分析表明，噬菌体SSP49利用细胞壁磷壁酸作为宿主受体。全基因组测序显示，SSP49的基因组大小为137,283bp，包含191个开放阅读框。噬菌体SSP49的基因组不包含与溶菌原形成相关的基因，细菌毒性，和抗生素耐药性，表明其在食品应用中的安全性。噬菌体SSP49的活性在各种高温和pH条件下相当稳定。此外，噬菌体SSP49在4°C和25°C下都有效地抑制了小菠菜叶上的金黄色葡萄球菌生长，同时在处理期间保持了活性噬菌体的数量（分别降低了1.2和2.1logCFU/cm2）。因此，这项研究证明了噬菌体SSP49作为新鲜农产品中金黄色葡萄球菌污染的替代天然生物防治剂的潜力。
