Development of a loop-mediated isothermal amplification assay for detection of Cronobacter spp. (Enterobacter sakazakii).
Contamination of Cronobacter spp. (Enterobacter sakazakii) in infant formulas and other food products is a severe problem. Here a loop-mediated isothermal amplification (LAMP) assay was developed for rapidly detecting Cronobacter spp. in powdered infant formula. Sequences of 16S/23S rDNA internal intergenic spacer of Cronobacter spp. were used as the target template to design LAMP primers. The detection outcome can be evaluated by the white precipitate or the fluorescence intensity under ultraviolet irradiation, both visible to naked eyes. The sensitivity and specificity of the LAMP assay was further analyzed in comparison with that of regular PCR and real time quantitative PCR. The results showed that all of Cronobacter spp. strains display positive reaction to the detections while all of the non-Cronobacter spp. strains were negative, and that the LAMP assay exhibits a high sensitivity of 9.1 fg/μL (The sensitivity of regular PCR and real time quantitative PCR is 91 and 9.1 pg/μL, respectively.). The amplified reaction could be accomplished in about 1 h, with the results visible to naked eyes. Hence, the LAMP assay developed by this study can provide a rapid and simple approach for the detection of Cronobacter spp. in infant formula.
Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, China Jiliang University, Xueyuan Street, Xiasha Higher Education Zone, Hangzhou 310018, China.
Xu
X
Liu
Jiehong
J
Fang
Mingzhou
M
Zhang
Xueyan
X
Wang
Weifen
W
Wang
Yunfei
Y
Gong
Xi
X
Xi
Mujie
M
Li
D001431:Bacteriological Techniques / Q000379:methods*; D044083:Cronobacter sakazakii / Q000235:genetics / Q000302:isolation & purification*; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D006801:Humans; D007225:Infant Food / Q000382:microbiology*; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D012680:Sensitivity and Specificity
D017931:DNA Primers; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer