Determination of dominant serovars of Listeria monocytogenes strains isolated from spontaneous human abortion in Tehran/IRAN

Background: To assess the extent of Listeria monocytogenes dominant serotypes in causation of human spontaneous abortion by culture, biochemical, API methods and PCR (Polymerase Chain Reaction) analysis for the presence of virulence serotypes as 1/2a and 4b in Iran. Methods: A total of 258 samples comprising placental bits, vaginal swabs and blood were collected from123 patients with spontaneous abortion. Listeria monocytogenes was identified and confirm by culture, biochemical tests, serological test, API system, CAMP test, hemolytic on sheep blood agar. PI-PLC (Phosphatidyl Inositol specific Phospholipase C) assay, followed by Multiplex PCR to detected serotypes 1/2a and 4b. Results: Out of 258samples, 28 isolates of Listeria monocytogeneswere identified by different methods. All of isolates confirmed by PCR. Our search, showed from 123 patients, 28 of isolated (46.6%) Listeria monocytogenesstrains, 14(50%) belonging to serovar 1/2a, 10(35%) to serovar 4b and 4(14.2%) to other serovars respectively. Result of the PCR method agreed with those the recovery of pathogenic dominant serotypes (1/2a,4b) isolated from cases of spontaneous abortion, indicates the significance of Listeria infection in pregnant women. Conclusions: Based on our study, serovars 1/2a and 4b played a key role in the human spontaneous abortion. Data analysis also showed that these serovars (1/2a, 4b) are dominant serovars as a causative agent of the spontaneous abortion in pregnant women.

Keywords:

Humans , Listeria monocytogenes , spontaneous abortion , dominant serovars , hly gene , iap gene