<?php

$themeHelper = $this->helper('Wyomind\ElasticsearchCore\Helper\Theme');
$themeModel = $themeHelper->getThemeModel();

if ($themeModel == "Infortis/ultimo") {
    echo $block->getChildHtml("wyo.eln.listing.products.grid.ultimo");
} else {
    echo $block->getChildHtml("wyo.eln.listing.products.grid.default");
}