Miettinen M K, Björkroth K J, Korkeala H J
Department of Food and Environmental Hygiene, University of Helsinki, Finland.
Int J Food Microbiol. 1999 Feb 18;46(3):187-92. doi: 10.1016/s0168-1605(98)00185-8.
One dominating strain of serotype 1/2b was found when serotyping and pulsed-field gel electrophoresis (PFGE) patterns were used for the characterization of 41 Listeria monocytogenes isolates originating from an ice cream plant. Samples were taken from the production environment, equipment and ice cream during the years 1990-1997. Serotyping divided the isolates into two serovars, 1/2b and 4b. Three rare-cutting enzymes (ApaI, AscI and SmaI) were used in the creation of PFGE patterns. AscI resulted in the best restriction enzyme digestion patterns (REDPs) for visual comparison. Eight different AscI REDPs were obtained, whereas ApaI produced six and SmaI seven banding patterns. When one-band differences are taken into account, 12 different PFGE types were distinguished based on information obtained with all three enzymes. The dominant PFGE type was found to have persisted in the ice cream plant for seven years. Improved and precisely targeted cleaning and disinfection practices combined with structural changes making for easier cleaning of the packaging machine, resulted in eradication of L. monocytogenes from this plant.
在对源自一家冰淇淋厂的41株单核细胞增生李斯特菌分离株进行血清分型和脉冲场凝胶电泳（PFGE）分析时，发现了一种占主导地位的1/2b血清型菌株。样本采集于1990年至1997年期间的生产环境、设备和冰淇淋。血清分型将分离株分为两个血清型，即1/2b和4b。使用了三种稀有切割酶（ApaI、AscI和SmaI）来创建PFGE图谱。AscI产生了用于视觉比较的最佳限制性酶切图谱（REDPs）。获得了八种不同的AscI REDPs，而ApaI产生了六种，SmaI产生了七种条带模式。当考虑一条带的差异时，根据使用这三种酶获得的信息区分出了12种不同的PFGE类型。发现占主导地位的PFGE类型在冰淇淋厂持续存在了七年。改进并精准靶向的清洁和消毒措施，以及对包装机进行便于清洁的结构改造，使得该工厂的单核细胞增生李斯特菌被根除。
