Serotyping of Listeria monocytogenes Isolates from Women with Spontaneous Abortion Using Polymerase Chain Reaction Method

  Listeria monocytogenes infection during pregnancy may cause spontaneous abortion or stillbirth, or the birth of babies with neonatal meningitis. The aim of this study was to serotype L. monocytogenes isolated from women with spontaneous abortion using polymerase chain reaction.

  Vaginal swab samples were obtained from 96 women with spontaneous abortion. The microbial culture was performed on blood agar and PALCAM agar followed by differential biochemical tests for characterization of L. monocytogenes isolates. Besides, total DNA was extracted from each vaginal specimen, and PCR assay was then carried out using specific primers for target genes of this bacterial species.

   Microbial culture and PCR revealed 4 and 16 L. monocytogenes isolates (out of 96 vaginal specimens), respectively. There was a significant association between consuming unsterilized dairy products and the risk of Llisteria infection (P < 0.001). Various serotypes of L. monocytogenes were detected as follows; the serotypes 1/2b, 3b (31.25%), the serotypes 1/2c, 3c (31.25%), the serotypes 1/2a, 3a (25%), and the serotypes 4 (12.5%).

  However, the difference between frequencies of observed serotypes was not statistically significant (P < 0.05). The 1/2b, 3b, and 1/2c, 3c serotypes of L. monocytogenes are more commonly seen in vaginal specimens of women with spontaneous abortion, and PCR technique as a convenient tool may be used for identifying of causative strains. However, further studies need to improve and optimize this approach.