Molecular identification and subtyping of Listeria monocytogenes based on hly and actA genes

Aim To establish the method for identifying and subtyping the isolates of Listeria monocytogenes.Method The specific hly,actA genes of Listeria monocytogenes isolates were amplified respectively.The amplified fragments of actA gene were sequenced and then analyzed with MEGA2 version software,and then the phylogenetic tree of Listeria monocytogenes was established.Result The 850bp fragment of amplified hly gene fragment was yielded in all Listeria monocytogenes,while in non- Listeria monocytogenes,this specific fragment didn't occur.These Listeria monocytogenes could be divided into two different lineages with this DNA-based subtyping technique.Conclusion The hly gene-based PCR method for identifying Listeria monocytogenes yielded high specificity and sensitivity.The establishment of DNA-based subtyping method provided new insight for studying the population genetics,ecology and epidemiology of Listeria monocytogenes.