public function indexAction()
 {
     $orden = (string) $this->_request->getParam('orden', 0);
     $asc = (bool) $this->_request->getParam('asc', 0);
     if (empty($orden)) {
         $orden = "id";
     }
     if ($asc) {
         $orden .= " ASC";
     } else {
         $orden .= " DESC";
     }
     $this->view->orden_asc = $asc;
     $this->view->subtitle = $this->info->sitio->usuarios->index->titulo;
     $this->view->usuarios = Usuarios::getAll($this->session->sitio->id, 0, $orden);
     $this->render();
 }
<?php

$usr = new Usuarios();
$usuarios = $usr->getAll();
ob_start();
?>
<div class='row'>
    <h1>Administraci&oacute;n de Usuarios</h1>
    <a href="?op=new" class="btn btn-default btn-sm" role="button">Nuevo</a> <br><br>
    <table class='table table-hover table-striped'>
        <thead>
            <tr>
                <th>Usuario</th>
                <th>Apellidos</th>
                <th>Nombres</th>
                <th>Nivel</th>
                <th>Acciones</th>
            </tr>            
        </thead>
        <tbody>
            <?php 
foreach ($usuarios as $u) {
    ?>
            <tr>
                <td><span class="glyphicon glyphicon-user"></span><?php 
    echo " " . $u['usuario'];
    ?>
</td>
                <td><?php 
    echo $u['apellidos'];
    ?>