Answer myself:
It looks like this will not supported. I do it like this now.
$reservations = $query->matching(
$query->logicalOr(
$query->equals('run', '27'),
$query->like($'run', '27,%'),
$query->like($'run', '%,27'),
$query->like($'run', '%,27,%')
)
)->execute();
lg arno