10x
I think I solved using the compat libraries
I installed mysql-libs-5.1.52-1.el6_0.1.x86_64 from the vendor
From REMI I installed ...
[root@host-8-59 mysql]# rpm -qa | grep remi
php-5.3.6-4.el6.remi.x86_64
php-mbstring-5.3.6-4.el6.remi.x86_64
php-mcrypt-5.3.6-4.el6.remi.x86_64
php-pdo-5.3.6-4.el6.remi.x86_64
php-ldap-5.3.6-4.el6.remi.x86_64
php-xml-5.3.6-4.el6.remi.x86_64
compat-mysql55-5.5.11-1.el6.remi.x86_64
php-common-5.3.6-4.el6.remi.x86_64
php-bcmath-5.3.6-4.el6.remi.x86_64
php-pear-1.9.3-2.el6.remi.noarch
php-soap-5.3.6-4.el6.remi.x86_64
php-mysql-5.3.6-4.el6.remi.x86_64
php-oci8-5.3.6-4.el6.remi.x86_64
php-cli-5.3.6-4.el6.remi.x86_64
php-pecl-rrd-1.0.3-1.el6.remi.x86_64
It seems this setup is stable.