Evaluation the Expression Level of inlB and Cell Invasion in Listeria monocytogenes Isolated from Pregnant Women

Abstract

Introduction: Listeria monocytogenes is known as a potentially pathogen, which can cause perinatal listeriosis, results in abortion, stillbirth or premature birth. Different factors are involved in the pathogenesis, including internalin B, which mediates the internalization of bacteria into a broad range of cell lines. However, it is not clear if expression of this protein is the same between different isolates. Methods: This study was conducted with the aim to compare L. monocytogenes isolated from pregnant women (n= 7) with different pregnancy outcomes (including healthy birth, still birth or blindness) and with abortion (n= 1), regarding expression level of inlB (internalin B encoding gene) and cell invasion. Results: Despite overexpression of inlB in most of the isolates, there was heterogeneity in the expression level between different isolates and no significant association with cell invasion and/ or pregnancy outcome was found (P> 0.05). About half of the studied isolates were able to invade HepG2 cells, while invasion to HeLa cells (cervix carcinoma cell line) was found only in one isolate. However, the difference was not significant. Likewise, no meaningful association was found between cell invasion and pregnancy outcomes. Conclusion: The expression level of inlB and cell invasion, cannot explain the difference of isolates in pathogenicity. Further studies are needed to identify bacterial and possibly host determinants.

Keywords

• listeria monocytogenes
• internalin b
• cell invasion
• pregnancy
• abortion.