Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, P,O, Box 57, FIN-00014, Helsinki, Finland.
BMC Vet Res. 2013 Nov 11;9:227. doi: 10.1186/1746-6148-9-227.
Coagulase-negative staphylococci (CNS) cause usually subclinical or mild clinical bovine mastitis, which often remains persistent. Symptoms are usually mild, mostly only comprising slight changes in the appearance of milk and possibly slight swelling. However, clinical mastitis with severe signs has also been reported. The reasons for the differences in clinical expression are largely unknown. Macrophages play an important role in the innate immunity of the udder. This study examined phagocytosis and killing by mouse macrophage cells of three CNS species: Staphylococcus chromogenes (15 isolates), Staphylococcus agnetis (6 isolates) and Staphylococcus simulans (15 isolates). Staphylococcus aureus (7 isolates) was also included as a control.
All the studied CNS species were phagocytosed by macrophages, but S. simulans resisted phagocytosis more effectively than the other CNS species. Only S. chromogenes was substantially killed by macrophages. Significant variations between isolates were seen in both phagocytosis and killing by macrophages and were more common in the killing assays. Significant differences between single CNS species and S. aureus were observed in both assays.
This study demonstrated that differences in the phagocytosis and killing of mastitis-causing staphylococci by macrophages exist at both the species and isolate level.
凝固酶阴性葡萄球菌（CNS）通常引起亚临床或轻度临床奶牛乳腺炎，且通常持续存在。症状通常较轻，主要只包括牛奶外观的轻微变化，可能有轻微肿胀。然而，也有严重症状的临床乳腺炎报告。临床表现差异的原因在很大程度上尚不清楚。巨噬细胞在乳房的先天免疫中起重要作用。本研究检查了三种 CNS 物种（15 株染色葡萄球菌、6 株嗜银葡萄球菌和 15 株模拟葡萄球菌）和金黄色葡萄球菌（7 株）的鼠巨噬细胞的吞噬和杀伤作用。
所有研究的 CNS 物种都被巨噬细胞吞噬，但 S. simulans 比其他 CNS 物种更有效地抵抗吞噬。只有 S. chromogenes 被巨噬细胞大量杀死。在吞噬和巨噬细胞杀伤中，在种间和种内都观察到显著的差异，在杀伤试验中更为常见。在两种试验中，单个 CNS 物种与金黄色葡萄球菌之间均存在显著差异。
本研究表明，巨噬细胞对乳腺炎相关葡萄球菌的吞噬和杀伤存在种间和种内差异。
