Index: wp-content/plugins/akismet/akismet.php
===================================================================
--- wp-content/plugins/akismet/akismet.php	(revision 355648)
+++ wp-content/plugins/akismet/akismet.php	(working copy)
@@ -437,9 +437,10 @@
 
 	delete_option('akismet_available_servers');
 
+	$prefix = $wpdb->get_blog_prefix();
 	$comment_errors = $wpdb->get_col( "
 		SELECT comment_id
-		FROM {$wpdb->prefix}commentmeta
+		FROM {$prefix}commentmeta
 		WHERE meta_key = 'akismet_error'
 		LIMIT 100
 	" );
Index: wp-includes/capabilities.php
===================================================================
--- wp-includes/capabilities.php	(revision 17501)
+++ wp-includes/capabilities.php	(working copy)
@@ -98,7 +98,7 @@
 	 */
 	function _init () {
 		global $wpdb, $wp_user_roles;
-		$this->role_key = $wpdb->prefix . 'user_roles';
+		$this->role_key = $wpdb->get_blog_prefix() . 'user_roles';
 		if ( ! empty( $wp_user_roles ) ) {
 			$this->roles = $wp_user_roles;
 			$this->use_db = false;
@@ -516,7 +516,7 @@
 	function _init_caps( $cap_key = '' ) {
 		global $wpdb;
 		if ( empty($cap_key) )
-			$this->cap_key = $wpdb->prefix . 'capabilities';
+			$this->cap_key = $wpdb->get_blog_prefix() . 'capabilities';
 		else
 			$this->cap_key = $cap_key;
 		$this->caps = &$this->{$this->cap_key};
@@ -662,7 +662,7 @@
 	function update_user_level_from_caps() {
 		global $wpdb;
 		$this->user_level = array_reduce( array_keys( $this->allcaps ), array( &$this, 'level_reduction' ), 0 );
-		update_user_meta( $this->ID, $wpdb->prefix . 'user_level', $this->user_level );
+		update_user_meta( $this->ID, $wpdb->get_blog_prefix() . 'user_level', $this->user_level );
 	}
 
 	/**
@@ -704,7 +704,7 @@
 		global $wpdb;
 		$this->caps = array();
 		delete_user_meta( $this->ID, $this->cap_key );
-		delete_user_meta( $this->ID, $wpdb->prefix . 'user_level' );
+		delete_user_meta( $this->ID, $wpdb->get_blog_prefix() . 'user_level' );
 		$this->get_role_caps();
 	}
 
Index: wp-includes/ms-blogs.php
===================================================================
--- wp-includes/ms-blogs.php	(revision 17501)
+++ wp-includes/ms-blogs.php	(working copy)
@@ -475,7 +475,7 @@
 	}
 
 	$wpdb->set_blog_id($new_blog);
-	$table_prefix = $wpdb->prefix;
+	$table_prefix = $wpdb->get_blog_prefix();
 	$prev_blog_id = $blog_id;
 	$blog_id = $new_blog;
 
@@ -541,7 +541,7 @@
 	$wpdb->set_blog_id($blog);
 	$prev_blog_id = $blog_id;
 	$blog_id = $blog;
-	$table_prefix = $wpdb->prefix;
+	$table_prefix = $wpdb->get_blog_prefix();
 
 	if ( is_object( $wp_roles ) ) {
 		$wpdb->suppress_errors();
Index: wp-includes/user.php
===================================================================
--- wp-includes/user.php	(revision 17501)
+++ wp-includes/user.php	(working copy)
@@ -262,9 +262,9 @@
 
 	// Keys used as object vars cannot have dashes.
 	$key = str_replace('-', '', $option);
-
-	if ( isset( $user->{$wpdb->prefix . $key} ) ) // Blog specific
-		$result = $user->{$wpdb->prefix . $key};
+	$prefix = $wpdb->get_blog_prefix();
+	if ( isset( $user->{$prefix . $key} ) ) // Blog specific
+		$result = $user->{$prefix . $key};
 	elseif ( isset( $user->{$key} ) ) // User specific and cross-blog
 		$result = $user->{$key};
 	else
@@ -295,7 +295,7 @@
 	global $wpdb;
 
 	if ( !$global )
-		$option_name = $wpdb->prefix . $option_name;
+		$option_name = $wpdb->get_blog_prefix() . $option_name;
 
 	// For backward compatibility. See differences between update_user_meta() and deprecated update_usermeta().
 	// http://core.trac.wordpress.org/ticket/13088
@@ -324,7 +324,7 @@
 	global $wpdb;
 
 	if ( !$global )
-		$option_name = $wpdb->prefix . $option_name;
+		$option_name = $wpdb->get_blog_prefix() . $option_name;
 	return delete_user_meta( $user_id, $option_name );
 }
 
@@ -1101,7 +1101,7 @@
 		$user->{$key} = $value;
 	}
 
-	$level = $wpdb->prefix . 'user_level';
+	$level = $wpdb->get_blog_prefix() . 'user_level';
 	if ( isset( $user->{$level} ) )
 		$user->user_level = $user->{$level};