In the present study, immunoglobulin Y (IgY) antibodies were raised in hens against the surface staphylococcal protein A (SpA) of Staphylococcus aureus. Anti-SpA IgY were tested in vitro for diagnostic applications, bacteriostatic, and biofilm inhibition effects. A specific and sensitive immunocapture PCR (IPCR) was developed to detect S. aureus from food, clinical, and environmental samples. Anti-SpA IgY were used for capturing S. aureus cells from different matrices. Chicken antibodies were chosen over mammalian antibodies based on its inertness to immunoglobulin (Ig)-binding property of SpA protein. No cross-reactivity was encountered with closely related Gram-positive and Gram-negative food pathogens. Inter-assay variation is < 10%. The assay was found suitable for testing on solid and liquid food samples, skin, and nasal swabs. The assay showed limit of detection of ≥ 102 CFU/mL from broth cultures and 102 to 103 CFU/ml from diverse natural samples. This assay overcomes the false positives commonly encountered while using mammalian immunoglobulins (IgG). Anti-SpA IgY antibodies were tested for their bacteriostatic effect on the growth of S. aureus. IgY antibodies at a concentration of 150 μg/ml inhibited the growth of S. aureus completely indicating the potential of IgY antibodies in neutralization of infectious pathogens. Similarly, anti-SpA IgY at MIC50 concentration reduced biofilm formation by ~ 45%. In view of advantages offered by IgY antibodies for specific detection of S. aureus in immunocapture PCR (IPCR) assay and in vitro neutralization potential of S. aureus, we recommend using IgY over conventional IgG of mammals involving S. aureus and its antigens. KEY POINTS: • IPCR with anti-SpA IgY for S. aureus was specific and sensitive for natural samples. • Anti-SpA IgY at 150 ug/ml displayed growth inhibition of S. aureus strains temporarily. • Anti-SpA IgY at MIC50 concentrations inhibited the biofilm formation partially.

中文翻译：

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针对金黄色葡萄球菌的葡萄球菌蛋白A（SpA）的IgY抗体在检测和预防功能中的应用。

在本研究中，针对金黄色葡萄球菌的表面葡萄球菌蛋白A（SpA）的母鸡产生了免疫球蛋白Y（IgY）抗体。在体外测试了抗SpA IgY的诊断应用，抑菌和生物膜抑制作用。开发了一种特异性和灵敏的免疫捕获PCR（IPCR），可从食品，临床和环境样品中检测金黄色葡萄球菌。抗SpA IgY用于捕获来自不同基质的金黄色葡萄球菌细胞。基于鸡抗体对SpA蛋白的免疫球蛋白（Ig）结合特性的惰性，选择了鸡抗体而不是哺乳动物抗体。与紧密相关的革兰氏阳性和革兰氏阴性食品病原体没有交叉反应。批间差异<10％。发现该测定法适合测试固体和液体食物样品，皮肤和鼻拭子。该测定法显示出肉汤培养物中检出限≥102 CFU / mL，各种自然样品中检出限为102至103 CFU / ml。该测定法克服了使用哺乳动物免疫球蛋白（IgG）时经常遇到的假阳性现象。测试了抗SpA IgY抗体对金黄色葡萄球菌生长的抑菌作用。浓度为150μg/ ml的IgY抗体可抑制金黄色葡萄球菌的生长，完全表明IgY抗体具有中和感染性病原体的潜力。同样，MIC50浓度下的抗SpA IgY将生物膜形成减少了约45％。考虑到IgY抗体在免疫捕获PCR（IPCR）分析中特异性检测金黄色葡萄球菌提供的优势以及金黄色葡萄球菌的体外中和潜力，我们建议使用IgY优于涉及金黄色葡萄球菌及其抗原的哺乳动物的常规IgG。要点：•对于金黄色葡萄球菌，具有抗SpA IgY的IPCR对天然样品具有特异性和敏感性。•150 ug / ml的抗SpA IgY暂时显示了金黄色葡萄球菌菌株的生长抑制。•MIC50浓度的抗SpA IgY部分抑制了生物膜的形成。