Evaluation of hly-A and 16S rRNA genes for detection of Listeria monocytogenes in raw milk sample

Listeria monocytogenes (L. monocytogenes) is a pathogen that causes meningitis, septicemia, and abortion in humans. These microorganisms can be transmitted through food.The aim of this study is a comparison of the two important target hemolysin A (hly-A) and 16S ribosomal ribonucleic acid (16S rRNA)genes in the early detection of L. monocytogenes in raw milk samples by polymerase chain reaction (PCR) assay.

In this cross-sectional study, one hundred samples of raw milk were collected from Damavand City, northern part of Iran, in 2015. After deoxyribonucleic acid (DNA) extraction, the PCR was optimized by using hly-A and 16S rRNA genes. After purification, thePCR product was cloned using a thermocontact TA cloning kitand vector pTZ57R. Data analysis was performed using MINITAB software (Mtb.exe). The chi-square test was used for the statistical test (P < 0.05).

Out of 100 samples, 13 samples have been positive for hly-A and 11 samples have been recognized as positive for 16S rRNA.

Results of our study show that the hly-A target gene has higher performance in molecular diagnosis of L. monocytogenes than 16S rRNA.