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目的对在Baird-Parker琼脂平板上被抑制的金黄色葡萄球菌(以下简称金葡菌)的遗传特征进行深入研究,并提出针对性检验措施。方法通过对127株不同来源的金葡菌和8株金葡菌标准菌株在Baird-Parker琼脂平板上进行测试,筛选在Baird-Parker琼脂平板上被抑制的金葡菌,并对菌株的遗传特征进行分析,同时检测Baird-Parker琼脂平板中的抑菌成分对金葡菌的抑制作用。结果 3株分离自北京猪肉馅中的菌株和金葡菌标准菌株(CMCC 26112)在Baird-Parker琼脂上生长率低于万分之一,Baird-Parker琼脂基础培养基中添加甘氨酸(12.0 g/L)可明显抑制这4株金葡菌的生长,而六水合氯化锂(5.0 g/L)、丙酮酸钠(10.0 g/L)和卵黄亚碲酸钾(50 ml)的添加对这4株金葡菌的生长没有明显影响;这4株菌在高盐甘露醇琼脂和科马嘉显色平板上的生长率均高于60%;脉冲场电泳(PFGE)分析发现,北京来源的3株金葡菌为同一PFGE型别,与标准菌株(CMCC 26112)存在明显差异。结论为保证食品安全国家标准检验方法 GB 4789.10—2010对不同金葡菌计数的覆盖性,计数检验过程中应使用两种或两种以上金葡菌选择性平板。
Objective To further study the genetic characteristics of Staphylococcus aureus (hereinafter referred to as Staphylococcus aureus) inhibited on Baird-Parker agar plates and to propose targeted test measures. Methods A total of 127 Staphylococcus aureus and 8 Staphylococcus aureus isolates from different origins were tested on Baird-Parker agar plates to screen Staphylococcus aureus that was inhibited on Baird-Parker agar plates. The genetic characteristics of the strains The assay was also performed to detect the inhibitory effect of the bacteriostatic components of Baird-Parker agar plates on S. aureus. Results The growth rate of Baird-Parker agar was less than 1/100 that of the strains isolated from Beijing pork paste and the Staphylococcus aureus standard strain (CMCC 26112). Glycine was added to Baird-Parker agar basal medium (12.0 g / L) significantly inhibited the growth of the four Staphylococcus aureus while the addition of lithium chloride hexahydrate (5.0 g / L), sodium pyruvate (10.0 g / L) and yolk potassium tellurite (50 ml) 4 strains of Staphylococcus aureus did not affect the growth of these 4 strains of high-salt mannitol agar and Komaga color plates were higher than the growth rate of 60%; pulsed field electrophoresis (PFGE) analysis found that Beijing-origin 3 Staphylococcus aureus for the same PFGE type, and the standard strain (CMCC 26112) there are significant differences. Conclusion In order to ensure the coverage of different Staphylococcus aureus by National Standard Test Method for Food Safety GB 4789.10-2010, two or more Staphylococcus aureus selective plates should be used in the counting test.