Parse Error

Parse error: syntax error, unexpected T_STRING in /home/wrightbo/public_html/man-health.net/wordpress/wp-config.php on line 28.

This is line 28:

/** MySQL hostname */
define(‘DB_HOST’, ‘localhost’);

Looks exactly the same as all my other wp sites cannot see what the problem is unless its something to do with localhost which so far after 8 wp sites I have not needed to touch.
Anyone out there give me a clue?