Development and evaluation of a DNA microarray for Listeria monocytogenes detection

Objective To develop a rapid and sensitive DNA microarray for Listeria monocytogenes detection. Methods A DNA microarray was developed using gyrB, 1SR, 16S rRNA, 23S rRNA, hlyA, iap and pgCA as the target genes and tested against 18 different species of known reference for repeatability, sensitivity, and specificity to verify the effectiveness of the chip. Results After testing of samples by the LM array, results show that the 70 mer Oligos synthesized by IDT are superior to the Oligos synthesized by Sagon with respect to both probe spotting or samples detection. The comparison of 3 spotting probe concentrations of 10 μmol/L, 40 μmol/L and 80 μmol/L demonstrated that the 10 μmol/L probes result in good detection signals equivalent to the 40 μmol/L and 80 μmol/L probes. The repeatability and sensitivity evaluated by sample testing on the LM array revealed that the chips developed in this study have good repeatability and the lower limit of sample detection is 0.9 ng DNA. The LM array can distinguish clearly and definitively between Listeria and non-Listeria bacteria in the sample. Conclusion The microarray is able to rapidly detect and identify Listeria monocytogenes. Key words: Listeria monocytogertes;  DNA microarray;  Oligo probe