Searching all WP installs for 'admin' usernames (10.4.4)

[aWEBthatWORKS]

We've got quite a few WordPress installs running on our server, some of which were migrated from an older version of Plesk. I'm concerned about the security of having 'admin' as their username. Is there any way I can search all the databases server-wide for this field in MySQL?

 

[IgorG]

It is apsc database. I think that it is admin_name field in aps_registry_object_setting table.