二级处理出水中沙门菌的改良多管发酵最大可能数定量检测方法

Improved MPN Quantitative Detection Method of Salmonella in Treated Wastewater

目的建立二级处理出水中沙门菌的改良多管发酵最大可能数(most probable number,MPN)定量检测方法。方法以某污水处理厂二沉池出水为水样,比较了滤膜法和改进的MPN法对沙门菌定量计数的结果。以滤膜法比较了木糖赖氨酸去氧胆酸盐琼脂(XLD)培养基、Hekton Enteric Agar(HE)培养基、亚硫酸铋琼脂(BS)培养基对水样中沙门菌的选择分离效果。采用改进的MPN法并以PCR法作为最后的鉴定手段,考察了四硫磺酸钠煌绿(TTB)增菌液、亚硒酸盐胱氨酸(SC)增菌液、氯化镁孔雀绿(MM)增菌液在37、42℃培养24、48h的选择性增菌效果。结果滤膜法中三种选择性培养基都无法对沙门菌进行准确计数。采用改进的MPN法,选用MM增菌液在42℃培养24h后的选择性增菌效果最好。结论改进的MPN法不仅具有良好的准确性和灵敏度,而且显著缩短检测时间,提高检测效率,适用于城市污水二级处理出水中沙门菌的监测。

Objeetive To establish the improved MPN quantitative detection method of Salmonella in treated wastewater. Methods The filtration method and improved MPN method were adopted to quantitatively detect Salmonella in treated wastewater. In the filtration method, separation effect of Salmonella was investigated by using three selective agar which including XLD,HE and BS,respectively. It was established that the improved MPN method in which PCR was used instead of the biochemical tests and serological identification to identify Salmonella. In the improved MPN method,the enrichment effect was researched by using SC,MM and TTB enriched broth in different time and temperature. Results In the filtration method, the Salmonella could not be counted accurately by the three kinds of selective agar. In the improved MPN method the optimized enrichment effect was determined as using MM enriched broth at 42% for 24 hours. Conclusion The improved MPN method is accurate, sensitive, quick and applicable to the quantitative detection of Salmonella in treated wastewater.