Comparison of sensitivities of agarose gel electrophoresis and nucleic acid blot hybridization in detecting bacterial virulence gene PCR product

Objective To explore the significance of nucleic acid blot hybridization applying in detecting bacterial virulence gene. Methods Polymerase chain reaction (PCR) was performed by using a tenfold serial dilution chromosome template of Enterohemorrhagic E. coli O157 ∶ H7 (strain EDL933) and Streptococcus suis serotype 2 (strain SC84) with the stx2-specific and cps2J-specific primer. 1% agarose gel electrophoresis (AGE) and nucleic acid blot hybridization were carried out to determine the detection limits of the amplification products. Results The detection limits of 1% AGE for stx2 and cps2J were estimated to be 6.7102 cfu(56.87 pg)/PCR and 4.3102 cfu(12.65 pg)/PCR. The detection limits of nucleic acid blot hybridization for stx2 and cps2J were estimated to be 6.710-1 cfu(56.87 fg)/PCR and 4.310-1 cfu(12.65 fg)/PCR. Conclusion The detection limits of nucleic acid blot hybridization for stx2 and cps2J were 1000 times higher than those of routine AGE.