Highlighting admin comments only

I’m trying to highlight just the admin comments in the comments list. I’ve tried a bunch of tutorials and I’ve had no luck. If someone could help/point me in the right direction it would be greatly appreciated.

In the comments.php file I’m calling wp_list_comments

<ol class="commentlist">
		<?php wp_list_comments('type=comment&callback=cnc_comment'); ?>
	</ol>

This is my function in the functions.php file:

// Comments Callbacks, Pingbacks and Style
	function cnc_comment($comment, $args, $depth) {
	   $GLOBALS['comment'] = $comment;
	   ?>
	   <li <?php comment_class(); ?> id="li-comment-<?php comment_ID() ?> ">
		 <div id="comment-<?php comment_ID(); ?>" >
		  <div class="comment-author vcard">
          <!--Avatar Call and Size -->
			 <?php echo get_avatar($comment,$size='48'); ?>
			 <?php printf(__('<cite class="fn">%s</cite> <span class="says">says:</span>'), get_comment_author_link()) ?>
		  </div>
		  <?php if ($comment->comment_approved == '0') : ?>
			 <em><?php _e('Your comment is awaiting moderation.') ?></em>
			 <br />
		  <?php endif; ?>

		  <div class="comment-meta commentmetadata"><?php printf(__('%1$s at %2$s'), get_comment_date(),  get_comment_time()) ?> <br /><?php edit_comment_link(__('[Edit Comment]'),'  ','') ?></div>
		  <div class="comment-body">
		  <?php comment_text() ?>
		  </div>
		  <div class="reply">
			 <?php comment_reply_link(array_merge( $args, array('depth' => $depth, 'max_depth' => $args['max_depth']))) ?>
		  </div>
		 </div>
	<?php
    }

Thanks in advance,
Mike