User-agent: Googlebot
Disallow: /wp-admin/
Allow: /wp-admin/admin-ajax.php

User-agent: msnbot
Disallow: /wp-admin/
Allow: /wp-admin/admin-ajax.php

User-agent: SemrushBot
Disallow: /

User-agent: *
Crawl-delay: 5
Disallow: /wp-admin/
Allow: /wp-admin/admin-ajax.php