婴幼儿奶粉中阪崎肠杆菌增菌培养对PCR快速检测的影响

Influence of Incubated Enrichment of Enterobacter Sakazakii in Infant Milk Powder on the PCR Rapid Detection

通过人工染菌方法,比较添加不同奶粉基质、不同初始菌量、不同增菌培养时间及添加不同干扰菌的情况下,阪崎肠杆菌的生长增殖变化,研究适合阪崎肠杆菌快速检测的最佳增菌时间。随着初始菌量的降低,阪崎肠杆菌生长延滞期延长,当初始菌量为1~9CFU/1 000 mL,阪崎肠杆菌增殖到10^(3)CFU/mL约需要10 h;含有奶粉基质的增菌液中目标菌增殖速度低于未添加奶粉的增菌液中的增殖速度;采用荧光PCR方法检测添加干扰菌后的阪崎肠杆菌的生长情况,含有大肠杆菌、沙门氏菌和金黄色葡萄球菌的增菌液在培养10 h可以检出阪崎肠杆菌,而添加阴沟肠杆菌的BPW增菌液需培养12 h能检出阪崎肠杆菌。因此,对幼儿乳粉增菌培养12 h后,对其增菌液进行PCR检测,即可快速且有效地检出阪崎肠杆菌。

The growth and multiplication of E.sakazakii with different milk powder medium, different initial amount of E.sakazakii, different enrichment medium time and different interference bacteria were studied through the method of artificial infection of BPW enrichment solution. The results showed that the growth delay period of E.sakazakii was prolonged with the decrease of initial bacterial count. When the initial bacterial count was 1-9 CFU/1 000 mL, it took about 10 h for E.sakazakii to multiplied to 10^(3)CFU/mL;the multiplication rate of E.sakazakii in BPW enrichment solution containing milk powder was lower than that in BPW enrichment solution without milk powder. The Real time PCR method was used to monitor the growth of E. sakazakii, the BPW enrichment solutions which was contaminated with E.sakazakii, Escherichia coli, Salmonella and Staphylococcus aureus were detected the E. sakazakii when the BPW enrichment solutions were incubated for 10 h, but the BPW enrichment medium which was contaminated with E. sakazakii and Enterobacter cloacae were detected the E. sakazakii when the BPW enrichment solutions were incubated for 12 h. Consequently, after 12 hours of enrichment for infant milk powder, Enterobacter sakazakii. Can be quickly and effectively detected by means of RT-PCR.