Nginx can’t see MySQL

I have a fully working Joomla 2.5.6 install driven by a local MySQL server, but I'd like to test nginx to see if it's a faster web serving experience than Apache.

• PHP 5.4.6 (PHP54w)
• CentOS 6.2
• Joomla 2.5.6
• PHP54w-fpm.i386 (FastCGI process manager)
• php -m shows: mysql & mysqli modules loaded

Nginx seems to have installed fine via yum, it can process a PHP-info file via FastCGI perfectly OK (http://37.128.190.241/php.php) but when I stop Apache, start nginx instead and visit my site I get: "Database connection error (1): The MySQL adapter 'mysqli' is not available."

I've tried adjusting my Joomla configuration.php to use mysql instead of mysqli but I get the same basic error, only this time "Database connection error (1): The MySQL adapter 'mysql' is not available" of course!

Can anyone think what the problem might be please? I did try explicitly setting extension = mysqli.so and extension = mysql.so in my php.ini to try and force the issue (despite php -m showing they were both successfully loaded anyway) – no difference.

I have a pretty standard nginx default.conf:

server {
    listen 80;
    server_name www.MYDOMAIN.com;
    server_name_in_redirect off;
    access_log /var/log/nginx/localhost.access_log main;
    error_log /var/log/nginx/localhost.error_log info;

    root /var/www/html/MYROOT_DIR;
    index index.php index.html index.htm default.html default.htm;
    # Support Clean (aka Search Engine Friendly) URLs
    location / {
            try_files $uri $uri/ /index.php?q=$uri&$args;
    }
    # deny running scripts inside writable directories
    location ~* /(images|cache|media|logs|tmp)/.*\.(php|pl|py|jsp|asp|sh|cgi)$ {
            return 403;
            error_page 403 /403_error.html;
    }
    location ~ \.php$ {
        fastcgi_pass  127.0.0.1:9000;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include /etc/nginx/fastcgi.conf;
    }
    # caching of files 
    location ~* \.(ico|pdf|flv)$ {
            expires 1y;
    }
    location ~* \.(js|css|png|jpg|jpeg|gif|swf|xml|txt)$ {
            expires 14d;
    }

}

Snip of output from phpinfo under nginx:

Server API    FPM/FastCGI
Virtual Directory Support    disabled
Configuration File (php.ini) Path    /etc
Loaded Configuration File    /etc/php.ini
Scan this dir for additional .ini files    /etc/php.d
Additional .ini files parsed    /etc/php.d/curl.ini, /etc/php.d/fileinfo.ini, /etc/php.d/json.ini, /etc/php.d/phar.ini, /etc/php.d/zip.ini

Snip of output from phpinfo under Apache:

Server API    Apache 2.0 Handler
Virtual Directory Support    disabled
Configuration File (php.ini) Path    /etc
Loaded Configuration File    /etc/php.ini
Scan this dir for additional .ini files    /etc/php.d
Additional .ini files parsed    /etc/php.d/curl.ini, /etc/php.d/fileinfo.ini, /etc/php.d/json.ini, /etc/php.d/mysql.ini, /etc/php.d/mysqli.ini, /etc/php.d/pdo.ini, /etc/php.d/pdo_mysql.ini, /etc/php.d/pdo_sqlite.ini, /etc/php.d/phar.ini, /etc/php.d/sqlite3.ini, /etc/php.d/zip.ini

Seems that with Apache, PHP is loading substantially more additional .ini files, including ones relating to mysql (mysql.ini, mysqli.ini, pdo_mysql.ini) than nginx.

Any ideas how I get nginix to also call these additional .ini's ?

Thanks in advance,

Steve