custom url with custom post

I want to change my custom post URL. I want to remove “item” from URL.

With the below code and with custom post type url plugin http://wordpress.org/plugins/custom-post-type-permalinks/
my URL is:

Original URL : http://mywebsite/wp/item/america/mayer/

Want to change it to http://mywebsite/wp/america/mayer/

Without using htaccess.

WordPress Code

    function aitDirItemPostType() {

        register_post_type( 'ait-dir-item',
            array(
                'labels' => array(
                    'name'          => 'Items',
                    'singular_name' => 'Item',
                    'add_new'       => 'Add new',
                    'add_new_item'  => 'Add new item',
                    'edit_item'     => 'Edit item',
                    'new_item'      => 'New item',
                    'not_found'     => 'No items found',
                    'not_found_in_trash' => 'No items found in Trash',
                    'menu_name'     => 'Items',
                ),
                'description' => 'Manipulating with items',
                'public' => true,
                'show_in_nav_menus' => true,
                'supports' => array(
                    'title',
                    'thumbnail',
                    'author',
                    'editor',
                    'excerpt',
                    'comments',
                ),
                'show_ui' => true,
                'show_in_menu' => true,
                'menu_icon' => AIT_FRAMEWORK_URL . '/CustomTypes/dir-item/dir-item.png',
                'menu_position' => $GLOBALS['aitThemeCustomTypes']['dir-item'],
                'has_archive' => true,
                'query_var' => 'dir-item',
                'rewrite' => array('slug' => 'item'),
                'capability_type' => 'ait-dir-item',
                'map_meta_cap' => true
            )
        );
        aitDirItemTaxonomies();

        flush_rewrite_rules(false);
    }

add_action( 'init', 'aitDirItemPostType');