Analysis of hlyA gene sequencing of Listeria monocytogenes isolated from Iraqi women with recurrent miscarriage

Abstract

Listeria monocytogenes is a causative agent of listeriosis and is regarded as one of the main foodborne pathogens. The transfer of L. monocytogenes to pregnant women occurs may cause miscarriage, stillbirth, or premature birth of the infected baby. This study was performed between November 2019 and June 2020, including 176 women with recurrent miscarriages at 17-46 years old who attended some Baghdad hospitals, in Iraq. The specimens were cervical swabs. Listeria agar was used for the isolation of L. monocytogenes and the isolates were identified with VITEK 2 system. The polymerase chain reaction was used for 16S rRNA and virulence genes (hlyA and inlA). The detection of variations of the hlyA gene sequence was done by using suitable software (MEGA6 and BioEdit). The recurrent miscarriages women with Listeria monocytogenes infections was 57 (32%) out of 176 aborted women and most aborted women with L. monocytogenes infection had previous abortions within the first trimester. The PCR products showed that 16S rRNA, hlyA, and inlA genes were detected in all identified isolates (100%). The results of alignment of the hlyA gene sequence revealed high similarity among the local isolates with strains reported from different parts of the world available in the public database, GenBank, on the other hand, the isolates L2 and L11 exhibited many variations at different positions of the gene sequence. It was found a high identity and phylogenetic relationship of the studied hlyA gene from 7 L. monocytogenes local isolates with those in European countries, Canada, and the USA which was found in strains isolated from foods and different infections. In conclusion, the detection of the virulence genes (hlyA and inlA) in addition to the housekeeping gene 16S rRNA, by PCR establishes the confirmation of L. monocytogenes identification, also some of the isolates may have variations that contribute to the severity of Listeria infections.