Distribution and Characterization of Dominant Serovars of Listeria monocytogenes in Human Spontaneous Abortion (Tehran)
Background and Objectives
Listeria monocytogenes is a facultative intracellular bacterium and the causative agent of listeriosis, a food-borne infection that can result in severe disease in humans and animals. The objective of this study was to determine the distribution of dominant serovars of L. monocytogenes isolated from spontaneous abortions in Tehran using phenotypic and genotypic methods.
Materials and Methods
In this study, 258 clinical samples including placental discharges, vaginal swabs, and blood were collected from 123 patients with spontaneous abortion. Bacteriological and serological tests were performed, and virulence-associated genes were detected using the Multiplex PCR assay.
Results
Out of all samples, 28 isolates of L. monocytogenes were recovered (10.8%). Among these isolates, 14 (50%) belonged to serovar 1/2a, 10 (35%) to serovar 4b, and 4 (14%) to other serovars. Serovar 4b was identified for the first time in human spontaneous abortion cases in Tehran. The presence of virulence genes including actA, hlyA, inlA, and inlB was confirmed in dominant isolates.
Conclusion
The findings indicate that the presence of virulence genes increases pathogenicity among dominant isolates. Serotypes lacking these genes exhibited lower virulence potential. The combined use of PI-PLC and molecular diagnostic assays could serve as efficient tools for identification of L. monocytogenes, especially in patients with spontaneous abortion.