Distribution and Characterization of Dominant Serovars of Listeria monocytogenes Strains Isolated from Spontaneous Human Abortion in Tehran

The aim was to determine the role of dominant serovars of Listeria monocytogenes (L. monocytogenes) in spontaneous abortions, using isolation methods and polymerase change reaction (PCR). A total of 258 samples comprising of placental tissue, vaginal swabs and blood were collected from 123 patients with spontaneous abortion. L. monocytogenes was identified and confirmed by culture, biochemical reactions, serological tests, API system, CAMP (Christie, Atkins, Munch and Petersen) test, and hemolysis on sheep blood agar. Phosphatidyl inositol specific phospholipase C (PI-PLC) assay, followed by multiplex PCR was applied for detection of serotypes 1/2a and 4b. Out of 258 samples, 28 isolates of L. monocytogenes were identified   by different methods. All of the isolates were confirmed by PCR. Of 28 isolated strains, 14(50%) belonged to serovar 1/2a, 10(35.7%) to serovar 4b and 4(14.3%) to other serovars. Based on our study, serovars 1/2a and 4b are dominant serovars as causative agents of human spontaneous abortion due to L. monocytogenes in pregnant women.