进出口食品中肠炎沙门氏菌的脉冲场凝胶电泳分子分型分析

Molecular Subtyping of Salmonella enteritidis in Imported and Exported Foods Using Pulsed Field Gel Electrophoresis

目的:分析近年深圳市进出口食品中分离的肠炎沙门氏菌菌株之间的相关性,初步建立食源性肠炎沙门氏菌脉冲场凝胶电泳分子分型数据库。方法:58株肠炎沙门氏菌菌株基因组DNA经XbaⅠ酶切,通过脉冲场凝胶电泳获得电泳图谱,利用BioNumerics软件对图谱进行聚类分析。结果:建立了深圳进出口食品中肠炎沙门氏菌DNA指纹图谱数据库。58株肠炎沙门氏菌分属18种脉冲场凝胶电泳图谱。聚类分析显示,58株肠炎沙门氏菌包含2个群,第1群主要为分离自美国进口禽肉的17株肠炎沙门氏菌,其相似性为91.45%,优势条带型为P2。第2群主要为分离自中国食品的36株肠炎沙门氏菌和分离自阿根廷的2株肠炎沙门氏菌,P8为优势条带型,相似性达到91.03%。结论:进出口食品中分离的肠炎沙门氏菌存在遗传谱系紧密相关的两个流行克隆群。

Objective： To explore the relationship among Salmonella enteritidis strains isolated from imported and exported foods in Shenzhen during 2005-2011, and develop a DNA fingerprint database of Salmonella enteritidis. Methods： Chromosomal DNAs from 58 isolates in agarose were digested with the restriction enzyme Xba I , and then were analyzed by pulsed-field gel electrophoresis （PFGE）. PFGE patterns were clustered using BioNumerics software. Results： DNA fingerprint database of imported and exported foods in Shenzhen was successfully developed. The results showed that there were 18 distractive PFGE patterns including 2 clusters. In cluster 1, Salmonella enteritidis strains isolated from American poultry meat products had 91.45% similarity, and pattern 2 was the dominant type. In cluster 2, 38 Salmonella enteritidis strains isolated from Chinese and Argentinian poultry meat products had 91.03% similarity and its dominant type was P8. Conclusion： There were two closely correlated pandemic clones of Salmonella enteritidis isolated from imported and exported foods. The development of DNA fingerprint database of imported and exported foods can contribute to develop molecular subtyping surveillance network for active surveillance and source tracking of food-borne pathogenic bacteria.