Table 1.
Bacterial species used in the real-time PCR and HRM analysis.
Figure 1.
Real time PCR and HRM analysis for all bacterial strains.
(a) Real time PCR amplification for Cronobacter spp. and other reference strains. All the non-Cronobacter strains and blank control had no amplification curve before 40 cycles. (b) Melting peaks of Cronobacter spp. 1, C. sakazakii including type strain ATCC 29544 and all isolates, Tm, 79.23±0.05°C. 2, C. muytjensii including type strain ATCC 51329, Tm, 80.11°C. (c) Normalized melting curves for Cronobacter spp. strains.
Figure 2.
Real time PCR and linear correlation of 10-fold serial dilution ofCronobacter spp. genomic DNA.
(a) amplification curves of diluted genomic DNA of Cronobacter spp., 1–7: dilutions 10 ng to 0.01 pg, respectively. (b) a linear regression of the data providing a formula of y = −1.2709x+19.274(R2 = 0.994), dilutions 10 ng to 0.01 pg, respectively.
Figure 3.
HRM analysis of 10-diluted genomic DNA (10 ng to 0.01 pg) from different type strains
(a) Melting peaks of type strain (ATCC 29544), Tm, 79.21±0.04°C. (b) Melting peaks of type strain (ATCC 51329), Tm, ATCC 51329, 80.06±0.08°C. (c) Normalized melting curves of both type strains (10 ng to 0. 1 pg).
Figure 4.
Alignment of theOmpA gene from Cronobacter spp. available in GenBank.
1: Cronobacter muytjensii (accession number: DQ000206.1); 2: Cronobacter sakazakii (accession number: GQ845410.1); 3: Cronobacter turicensis z3032 (accession number: FN543093.2).