Restaino L, Frampton E W, Irbe R M, Schabert G, Spitz H
R & F Laboratories, West Chicago, Illinois 60185, USA.
J Food Prot. 1999 Mar;62(3):244-51. doi: 10.4315/0362-028x-62.3.244.
The BCM Listeria monocytogenes detection system (LMDS) consists of a selective preenrichment broth (LMPEB), selective enrichment broth (LMSEB), selective/differential plating medium (LMPM), and identification on a confirmatory plating medium (LMCM). The efficacy of the BCM LMDS was determined using pure cultures and naturally and artificially contaminated environmental sponges. The BCM LMPEB allowed the growth of Listeria and resuscitation of heat-injured L. monocytogenes. The BCM LMSEB, which contains the fluorogenic substrate 4-methylumbelliferyl-myo-inositol-1-phosphate and detects phosphatidylinositol phospholipase C (PI-PLC) activity, provided a presumptive positive test for the presence of pathogenic Listeria (L. monocytogenes and L. ivanovii) after 24 h at 35 degrees C. An initial inoculum of 10 to 100 CFU/ml of L. monocytogenes in BCM LMSEB yielded a fluorogenic response after 24 h. On BCM LMPM, L. monocytogenes and L. ivanovii were the two Listeria species forming turquoise convex colonies (1.0 to 2.5 mm in diameter) from PI-PLC activity on the chromogenic substrate, 5-bromo-4-chloro-3-indoxyl-myo-inositol-1-phosphate. L. monocytogenes was distinguished from L. ivanovii by either its fluorescence on BCM LMCM or acid production from rhamnose. False-positive organisms (Bacillus cereus, Staphylococcus aureus, Bacillus thuringiensis, and yeasts) were eliminated by at least one of the media in the BCM LMDS. Using a pure culture system, the BCM LMDS detected one to two L. monocytogenes cells from a sponge rehydrated in 10 ml of DE neutralizing broth. In an analysis of 162 environmental sponges from facilities inspected by the U.S. Department of Agriculture (USDA), the values for identification of L. monocytogenes by BCM LMDS and the USDA method were 30 and 14 sites, respectively, with sensitivity and specificity values of 85.7 and 100.0% versus 40.0 and 66.1%, respectively. No false-positive organisms were isolated by BCM LMDS, whereas 26.5% of the sponges tested by the USDA method produced false-positive results.
BCM 单核细胞增生李斯特菌检测系统（LMDS）由选择性预增菌肉汤（LMPEB）、选择性增菌肉汤（LMSEB）、选择性/鉴别性平板培养基（LMPM）以及在确证平板培养基（LMCM）上进行鉴定组成。使用纯培养物以及天然和人工污染的环境海绵来确定 BCM LMDS 的效能。BCM LMPEB 能使李斯特菌生长并使热损伤的单核细胞增生李斯特菌复苏。BCM LMSEB 含有荧光底物 4-甲基伞形酮基-肌醇-1-磷酸，并能检测磷脂酰肌醇磷脂酶 C（PI-PLC）活性，在 35℃培养 24 小时后，对致病性李斯特菌（单核细胞增生李斯特菌和伊氏李斯特菌）的存在提供初步阳性检测结果。在 BCM LMSEB 中初始接种量为 10 至 100 CFU/ml 的单核细胞增生李斯特菌在 24 小时后产生荧光反应。在 BCM LMPM 上，单核细胞增生李斯特菌和伊氏李斯特菌是通过在显色底物 5-溴-4-氯-3-吲哚基-肌醇-1-磷酸上的 PI-PLC 活性形成绿松石色凸起菌落（直径 1.0 至 2.5 毫米）的两种李斯特菌。单核细胞增生李斯特菌可通过其在 BCM LMCM 上的荧光或从鼠李糖产酸与伊氏李斯特菌区分开来。假阳性微生物（蜡样芽孢杆菌、金黄色葡萄球菌、苏云金芽孢杆菌和酵母菌）被 BCM LMDS 中的至少一种培养基排除。使用纯培养系统，BCM LMDS 能从在 10 ml DE 中和肉汤中复水的海绵中检测到一至两个单核细胞增生李斯特菌细胞。在美国农业部（USDA）检查的设施中对 162 个环境海绵进行分析时，BCM LMDS 和 USDA 方法鉴定单核细胞增生李斯特菌的位点分别为 30 个和 14 个，敏感性和特异性值分别为 85.7%和 100.0%，而 USDA 方法分别为 40.0%和 66.1%。BCM LMDS 未分离出假阳性微生物，而 USDA 方法检测的海绵中有 26.5%产生了假阳性结果。
