Braham R, Black W D, Claxton J, Yee A J
Department of Biomedical Sciences, University of Guelph, Ontario, Canada.
J Food Prot. 2001 Oct;64(10):1565-73. doi: 10.4315/0362-028x-64.10.1565.
Governments regulate antimicrobial residues in slaughtered animals with surveillance programs for detecting drugs in food-producing animals. Although initial screening bioassay systems are recognized for their sensitivities to antimicrobial drug groups, none are sensitive to sulfonamides at or near the maximum residue levels (MRLs) in the Codex Alimentarious. We have developed a sulfonamide-sensitive rapid assay using Bacillus stearothermophilus inoculated PM indicator agar containing bromcresol purple and trimethoprim, where the end point is a combination of color change in the agar and zone of microbial growth inhibition around the sampling disk. Five sulfonamides, plus 16 other antimicrobial drugs were tested in standard concentrations in water, bovine kidney, and ground beef. Sulfonamides were detected at concentrations near the MRLs, and they were presumptively identified using para-aminobenzoic acid. The rapid assay was extremely sensitive to beta-lactams that were presumptively identified using penase. The system also was sensitive to tetracyclines, aminoglycosides, and macrolides, of which tetracyclines and gentamicin were identified using enzyme-linked immunosorbent assay (ELISA). In trials on slaughterhouse tissues submitted for testing in Ontario's meat surveillance program, the rapid assay identified twofold the number of positive kidneys and threefold the number of positive diaphragm samples compared to a standard microbiological inhibition test (MIT) currently approved. Fifty-three of 471 carcasses were sulfonamide positive with the rapid assay, while no sulfonamides were detected with the MIT. ELISA and thin-layer chromatography were used on selected samples to confirm the rapid assay sulfonamide presumptive results.
政府通过对食用动物进行药物检测的监测计划来监管屠宰动物中的抗菌药物残留。尽管初始筛选生物测定系统因其对抗菌药物组的敏感性而得到认可，但在食品法典委员会规定的最大残留限量（MRLs）或接近该限量时，没有一种系统对磺胺类药物敏感。我们开发了一种对磺胺类药物敏感的快速检测方法，该方法使用接种了嗜热脂肪芽孢杆菌的含有溴甲酚紫和甲氧苄啶的PM指示琼脂，终点是琼脂颜色变化和采样盘周围微生物生长抑制区域的组合。对五种磺胺类药物以及其他16种抗菌药物在水、牛肾和碎牛肉中的标准浓度进行了测试。在接近最大残留限量的浓度下检测到了磺胺类药物，并使用对氨基苯甲酸进行了推定鉴定。该快速检测方法对使用青霉素酶进行推定鉴定的β-内酰胺类药物极其敏感。该系统对四环素类、氨基糖苷类和大环内酯类也敏感，其中四环素类和庆大霉素使用酶联免疫吸附测定（ELISA）进行鉴定。在安大略省肉类监测计划中提交检测的屠宰场组织试验中，与目前批准的标准微生物抑制试验（MIT）相比，快速检测方法鉴定出的阳性肾脏数量增加了一倍，阳性膈肌样本数量增加了两倍。在471具胴体中，有53具通过快速检测方法呈磺胺类药物阳性，而通过MIT未检测到磺胺类药物。对选定样本使用ELISA和薄层色谱法来确认快速检测方法对磺胺类药物的推定结果。
