Well you’ve Post ID with you. So you can use this custom function to retrieve slug of any post.
function get_the_slug( $id=null ){
if( empty($id) ):
global $post;
if( empty($post) )
return ''; // No global $post var available.
$id = $post->ID;
endif;
$slug = basename( get_permalink($id) );
return $slug;
}
This in return will provide you slug of specified post which you can pass as an argument. By default it’ll give you slug current post item.