Loop-mediated isothermal amplification assay for rapid detection of Enterobacter sakazakii in powdered infant formula

Abstract:

Abstract: [Objective] A loop-mediated isothermal amplification (LAMP) technology with two loop primers was developed for rapidly detecting Enterobacter sakazakii in powdered infant formula. [Methods] Sequences of 16S-23S rRNA of Enterobacter sakazakii (ATCC29544) were used as target sequences, to design outer primers, inner primers and loop primers. We judged the results of detection, through visible to the naked eye of the white precipitate. [Results]The sensitivity of the LAMP assay was 0.101 CFU/mL; the detection limit of artificial contamination was 1.1 CFU/g. The detection could be finished about an hour from dealing with the sample to report the results with DNA kit. Compared with LAMP, the sensitivity of the PCR assay was 101 CFU/mL and the detection limit of artificial contamination was 1100 CFU/g in three hours. To apply the same method of extracting DNA, from dealing with the sample to report the results, it took about three hours. [Conclusion] Therefore, this LAMP-based assay is sensitive and fast. These results indicate that LAMP can provide a rapid yet simple test for the detection of Enterobacter sakazakii in powdered infant formula.