$q = 'СТРОКА1';

$regex = new MongoRegex("/.*{$q}|ALL.*/i");

$regex_deny = new MongoRegex("/[^({$q})]/i");

$documents = $document_manager->getRepository('MyDocument')->findBy(array(

            'field1' => $regex,

            'field2' => $regex_deny,

        ));

/^(?!(.*СТРОКА1))/

/^(?!(.*{$q}))/