Chen Yu, Wu Da, Sun Min, Deng Mingjun, Cui Shuhua, Liang Chengzhu, Geng Juan, Sun Tao, Long Ling, Xiao Xizhi
College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China, 350002.
J AOAC Int. 2016 Jan-Feb;99(1):124-9. doi: 10.5740/jaoacint.15-0172. Epub 2016 Jan 28.
While inspecting animal feed for Salmonella contamination, we routinely observed bacterial colonies on selective agars that were similar in appearance to those formed by Salmonella. These were identified as Citrobacter freundii, Proteus mirabilis, and Serratia fonticola using biochemical and serological techniques. Because the presence of these bacterial species confounds identification of Salmonella, we refer to them as "interference bacteria." Polyvalent antisera against these interference bacteria were prepared by immunizing rabbits with a mixture of all three organisms. To minimize or eliminate interference by these bacteria, the polyvalent antisera were introduced between the steps of selective enrichment and Salmonella-selective plating. The antisera raised against the interference bacteria, when combined with neonatal rabbit complement, exhibited specific bactericidal activity against C. freundii, P. mirabilis, and S. fonticola. The respective serum bactericidal assay titers were 2(9), 2(8), and 2(10). In selective broth, polyvalent antisera could also kill the target bacterial cells effectively. We tested 526 samples (186 white fishmeal, 97 red fishmeal, and 243 cattle bone powder) using the polyvalent antisera and found that the rates of contamination of each species of the three respective foods decreased by 58.8, 100, and 83%. Our data indicates that polyvalent sera against C. freundii, P. mirabilis, and S. fonticola can be used as inhibitors to increase the accuracy of Salmonella detection.
在检查动物饲料中的沙门氏菌污染时，我们经常在选择性琼脂上观察到外观与沙门氏菌形成的菌落相似的细菌菌落。使用生化和血清学技术将这些菌落鉴定为弗氏柠檬酸杆菌、奇异变形杆菌和丰氏沙雷氏菌。由于这些细菌的存在会混淆沙门氏菌的鉴定，我们将它们称为“干扰菌”。通过用这三种生物体的混合物免疫兔子，制备了针对这些干扰菌的多价抗血清。为了最小化或消除这些细菌的干扰，在选择性富集和沙门氏菌选择性平板接种步骤之间引入了多价抗血清。针对干扰菌产生的抗血清与新生兔补体结合后，对弗氏柠檬酸杆菌、奇异变形杆菌和丰氏沙雷氏菌表现出特异性杀菌活性。各自的血清杀菌试验效价分别为2(9)、2(8)和2(10)。在选择性肉汤中，多价抗血清也能有效杀死目标细菌细胞。我们使用多价抗血清检测了526个样本（186份白鱼粉、97份红鱼粉和243份牛骨粉），发现这三种各自食物的每种污染率分别下降了58.8%、100%和83%。我们的数据表明，针对弗氏柠檬酸杆菌、奇异变形杆菌和丰氏沙雷氏菌的多价血清可作为抑制剂，以提高沙门氏菌检测的准确性。
