Intracellular Adaptation of <i>Listeria monocytogenes</i> and <i>Listeria ivanovii</i> Isolated from Fresh Produce in Côte d’Ivoire: An <i>in Vitro</i> Infection Stud

<i>Listeria monocytogenes</i> (<i>L. monocytogenes</i>) is a pathogen that frequently contaminates foods, and is the cause of listeriosis worldwide. Although <i>L. monocytogenes</i> is the primary species associated with human listeriosis, <i>Listeria ivanovii</i> (<i>L. ivanovii</i>) traditionally considered pathogenic mainly to ruminants has also been implicated in rare but severe infections in immunocompromised humans. The objectives of this study were to examine the ability of <i>L. monocytogenes</i> and <i>L. ivanovii</i> strains isolated from fresh vegetables and market garden produce in Abidjan, Côte d'Ivoire, to enter and multiply in JEG3 cells, to disseminate and to form LisCVs persistence vacuoles. After identification by 16sDNAr gene sequencing and serogrouping by PCR of <i>Listeria</i> strains isolated from fresh vegetables and market garden produce, three strains were identified as belonging to the species <i>L. monocytogenes</i> (2 strains, L208 and L238) and <i>L. ivanovii</i> (1 strain, L135). In vitro infection was carried out using JEG3 trophoblastic cells, with three reference strains (<i>L. monocytogenes</i> EGDe serotype 1/2a, <i>Listeria monocytogenes</i> CLIP80459 serotype 4b and <i>L. ivanovii</i> ATCC19119) serving as controls. The results showed that all the <i>Listeria</i> strains tested had similar characteristics in terms of their ability to penetrate, multiply and form LisCV, and higher cytotoxicity in <i>L. monocytogenes</i> species than in <i>L. ivanovii</i> in general. <i>L. monocytogenes </i>strains L208 and L238 showed similar invasion rates to <i>L. monocytogenes </i>CLIP80459.