多种食源性致病菌的基因芯片检测技术

DNA microarray technique for detecting food-borne pathogens

目的探讨随机PCR结合基因芯片技术用于多种食源性致病菌筛查检测的可行性。方法利用Clustal X和Oligo 6.0软件设计探针,进行生物信息学比对验证特异性,探针末端修饰后合成并制备基因芯片。使用锚定随机引物扩增细菌基因组DNA,偶联荧光染料的扩增产物与芯片杂交后扫描检测。对随机PCR及杂交反应等一系列检测条件进行优化。选取16种病原细菌进行芯片特异性验证,使用4种食源性致病菌DNA进行芯片灵敏度检测及重复性评价,制备细菌DNA混合样本和痢疾志贺菌模拟水污染样本对芯片检测效能进行初步考核。结果 9种食源性致病菌获得阳性结果,基因组DNA检测灵敏度102～103pg/μl,芯片重复性变异系数(CV)值<15%,混合样本检测与预期结果一致,最低可检测水样本中痢疾志贺菌的最低浓度为3.54×105cfu/ml。结论初步建立的基于随机引物PCR的基因芯片技术进行多种食源性致病菌检测的方法,为病原细菌高通量筛查检测提供了一种新的思路。

Objective To study the application of DNA microarray technique for screening and identifying multiple food- borne pathogens. Methods The oligonucleotide probes were designed by Clustal X and Oligo 6.0 at the conserved regions of specific genes of multiple food-borne pathogens, and then were validated by bioinformatic analyses. The 5＇ end of each probe was modified by amino-group and 10 Poly-T, and the optimized probes were synthesized and spotted on aldehyde-coated slides. The bacteria DNA template incubated with Klenow enzyme was amplified by arbitrarily primed PCR, and PCR products incorporated into Aminoallyl-dUTP were coupled with fluorescent dye. After hybridization of the purified PCR products with DNA microarray, the hybridization image and fluorescence intensity analysis was acquired by ScanArray and GenePix Pro 5.1 software. A series of detection conditions such as arbitrarily primed PCR and microarray hybridization were optimized. The specificity of this approach was evaluated by 16 different bacteria DNA, and the sensitivity and reproducibility were verified by 4 food-borne pathogens DNA. The samples of multiple bacteria DNA and simulated water samples of Shigella dysenteriae were detected. Results Nine different food-borne bacteria were successfully discriminated under the same condition. The sensitivity of genomic DNA was 10^2-10^3pg/ μ 1, and the coefficient of variation （CV） of the reproducibility of assay was less than 15%. The corresponding specific hybridization maps of the multiple bacteria DNA samples were obtained, and the detection limit of simulated water sample of Shigella dysenteriae was 3.54 × 10^5cfu/ml. Conclusions The DNA microarray detection system based on arbitrarily primed PCR can be employed for effective detection of multiple food-borne pathogens, and this assay may offer a new method for high-throughput platform for detecting bacteria.