Unable to execute use `database`

$dsn = "mysql:host=10.152.183.98;port=3306;dbname=test";

$pdo = new PDO($dsn, $config['username'], $config['password']);

$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

try {

    $res = $pdo->exec('use `test`');

} catch (PDOException $e) {

    var_dump($e->getMessage());

}

 error  : (30) [readwritesplit] (Splitter-Service) Lost connection to the master server, closing session. Lost connection to master server while connection was idle. Connection has been idle for 0 seconds. Error caused by: #HY000: Lost connection to backend server: connection closed by peer. Last close reason: <none>. Last error: 

error  : (30) Invalid authentication message from backend 'dbsrv1'. Error code: 1049, Msg : #42000: Unknown database '`test`'