Heilongjiang Provincial Key Laboratory of Prevention and Control of Bovine Diseases, College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, No. 5 Xinfeng Road, Daqing, 163319, P. R. China.
BMC Microbiol. 2021 Feb 20;21(1):57. doi: 10.1186/s12866-021-02117-1.
Staphylococcus aureus is the causative agent of chronic mastitis, and can form a biofilm that is difficult to completely remove once formed. Disinfectants are effective against S. aureus, but their activity is easily affected by environmental factors and they are corrosive to equipment and chemically toxic to livestock and humans. Therefore, we investigated the potential utility of a bacteriophage as a narrow-spectrum disinfectant against biofilms formed by S. aureus. In this study, we isolated and characterized bacteriophage vB_SauM_SDQ (abbreviated to SDQ) to determine its efficacy in removing S. aureus biofilms.
SDQ belongs to the family Myoviridae and consists of a hexagonal head, long neck, and short tail. This phage can sterilize a 10 CFU/mL culture of S. aureus in 12 h and multiply itself 1000-fold in that time. Biofilms formed on polystyrene, milk, and mammary-gland tissue were significantly reduced after SDQ treatment. Fluorescence microscopy and scanning electron microscopy showed that SDQ destroyed the biofilm structure. Moreover, the titer of SDQ remained relatively high after the lysis of the bacteria and the removal of the biofilm, exerting a continuous bacteriostatic effect. SDQ also retained its full activity under conditions that mimic common environments, i.e., in the presence of nonionic detergents, tap water, or organic materials. A nonionic detergent (Triton X-100) enhanced the removal of biofilm by SDQ.
Our results suggest that SDQ, a specific lytic S. aureus phage, can be used to control biofilm infections. SDQ maintains its full activity in the presence of nonionic detergents, tap water, metal chelators, and organic materials, and can be used in combination with detergents. We propose this phage as a narrow-spectrum disinfectant against S. aureus, to augment or supplement the use of broad-spectrum disinfectants in the prevention and control of the mastitis and dairy industry contamination caused by S. aureus.
金黄色葡萄球菌是慢性乳腺炎的病原体，并且一旦形成生物膜就难以彻底清除。消毒剂对金黄色葡萄球菌有效，但它们的活性容易受到环境因素的影响，对设备有腐蚀性，对牲畜和人类有化学毒性。因此，我们研究了噬菌体作为一种针对金黄色葡萄球菌生物膜的窄谱消毒剂的潜在用途。在本研究中，我们分离并鉴定了噬菌体 vB_SauM_SDQ（简称 SDQ），以确定其去除金黄色葡萄球菌生物膜的功效。
SDQ 属于肌尾噬菌体科，由六边形头部、长颈部和短尾部组成。这种噬菌体可在 12 小时内杀死 10 CFU/mL 的金黄色葡萄球菌培养物，并在 12 小时内自我繁殖 1000 倍。经 SDQ 处理后，聚苯乙烯、牛奶和乳腺组织上形成的生物膜明显减少。荧光显微镜和扫描电子显微镜显示，SDQ 破坏了生物膜结构。此外，在细菌裂解和生物膜去除后，噬菌体的效价仍相对较高，发挥持续的抑菌作用。SDQ 在模拟常见环境的条件下也保持较高的活性，即存在非离子型清洁剂、自来水或有机物质时。非离子型清洁剂（Triton X-100）增强了 SDQ 对生物膜的去除效果。
我们的结果表明，金黄色葡萄球菌特异性裂解噬菌体 SDQ 可用于控制生物膜感染。SDQ 在存在非离子型清洁剂、自来水、金属螯合剂和有机物质的情况下保持其全部活性，并且可以与清洁剂联合使用。我们建议将该噬菌体作为一种针对金黄色葡萄球菌的窄谱消毒剂，以增强或补充广谱消毒剂在预防和控制金黄色葡萄球菌引起的乳腺炎和乳制品行业污染中的应用。
