河北地区食源性单核细胞增生李斯特菌脂肪酸的分型研究

对脂肪酸分型方法在单核细胞增生李斯特菌(LM)菌株鉴定、菌株相似性分析等方面的应用价值进行评价。本研究选取2005~2007年从河北地区六大类食品中分离到的90株LM菌,提取脂肪酸,利用MIDI公司Sherlock系统进行菌体脂肪酸成分分析,使用SPSS 19.0软件对获得的数据资料进行统计分析及聚类分型,并将脂肪酸分型与传统的血清分型和分型金标准PFGE分型进行比较。结果表明,脂肪酸分析法判定LM菌的符合率为96.67%,所有菌株共检出20种脂肪酸成分,主要脂肪酸成分有3种,分别为脂肪酸15:0anteiso、17:0 anteiso和15:0 iso。各血清型间脂肪酸含量存在一定差异,血清1/2c型菌株与血清1/2a、1/2b和4b型菌株相比,有2种主要脂肪酸含量差异有统计学意义(P0.01)。与PFGE分型相比,在对结构简单的小样本资料的菌株亲缘关系鉴定中脂肪酸分型更具优势。将脂肪酸分型与血清学分型和PFGE分型相结合能够更好的分析LM菌菌株之间的相关性。

Fatty Aacid Typing Analysis of Food-borne Listeria monocytogenes in Hebei Area

In this study, the usefulness of fatty acid typing to identify and evaluate strain similarity among Listeria monocytogenes (LM) strains was evaluated. Ninety LM strains isolated from six types of food in Hebei area from 2005 to 2007 were selected for this study. The fatty acids were extracted, and their components were analyzed using the MIDI Sherlock system. SPSS 19. 0 statistical software was used for data and cluster analyses. The fatty acid typing was compared with traditional serotyping and pulsed-field gel electrophoresis (PFGE), which is the gold standard for typing. The results showed that the fatty acid analysis method successfully identified 96.67% of LM strains, 20 fatty acid components were detected from all of the tested strains, and the three main fatty acid components were 15:0 anteiso, 17:0 anteiso, and 15:0 iso. The fatty acid components differed among the different serotypes, and the differences in two main fatty acid components between serotype 1/2c isolates and serotype 1/2a, 1/2b, and 4b isolates were statistically significant (P < 0. 01). Compared with PFGE typing, fatty acid typing was a more efficient method for identifying genetic relationships between strains in small samples with simple structures. The combination of fatty acid typing along with serotyping and PFGE typing could better identify correlations among LM strains.