Here everything that I have:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule /providers/([A-Za-z0-9-.]+)/?$ /providers.php?s=$1 [L]
</IfModule>
(modRewrite is enabled on the server.)