本研究通过单因素试验和响应面分析试验建立了能够选择性富集沙门氏菌、副溶血弧菌和霍乱弧菌的共增菌培养基SVV, 采用平板计数法及三重荧光PCR技术验证了SVV的增菌效果。结果表明: SVV能同时富集以不同浓度比例混合的3种目标菌, 37oC振荡培养18 h后, 菌体浓度达到105~108 CFU/mL; SVV强烈抑制大部分的非目标菌; 用荧光PCR方法检测经过37oC振荡培养18 h的10份人工接种样品和608份实际样品, 结果表明目标菌在SVV中增殖18 h后菌量达到检测限以上, SVV联合荧光PCR检测方法的检出率为4.06%, 比传统检测方法(3.78%)高, 无假阴性和假阳性。SVV可望应用于水产品中沙门氏菌、副溶血弧菌和霍乱弧菌检测前的增菌处理, 可简化检测过程, 有效克服漏检, 提高检出率。
We formulated a selective enrichment broth (SVV) for simultaneous growth of Salmonella, Vibrio parahaemolyticus, and Vibrio cholerae by single factor experiment and response surface method. We evaluated the enrichment effect of SVV by conventional culture method and real-time PCR assay. We obtained the SVV broth by supplementting the Buffered Peptone Water (BPW) with bile salt no. 3, potassium tellurite, and sodium citrate as inhibitors, and glucose, mannitol, snhydrous sodium sulfite and sodium pyruvate as accelerants. We also modified the concentration of sodium chloride in BPW. When mixed at equal or varied proportions, the target pathogens had a great accumulation (105-108 CFU/mL) after incubated in SVV for 18 h at 37oC with shaking. It can also effectively inhibit the competitive microflora. We detected 10 artificial simulated samples and 608 real samples using SVV with real-time PCR. After enriched in SVV for 18 h, the quantity of the bacteria in samples were above the detection limit. The SVV with PCR assay showed higher tested positive (4.06%) compared to that of the converntional detection method (3.78%) and there was no false report. In summary, SVV is a promising new multiplex selective enrichment broth that can be used in detection of seafood.
新世纪优秀人才支持计划(No. NCET-06-0746), 粤港澳关键领域重点突破项目(No. 2007A0209002), 广东省教育部产学研结合项目(No. 2007B090400068)资助。