Please note that this will drop all users and logins that are LIKE '%PDK%'. It's unlikely that any other user will match that mask... but you should be sure.
DECLARE @username varchar(255)
declare @sql varchar(200)
DECLARE curName CURSOR LOCAL FAST_FORWARD FOR
select rtrim(name)
from sys.syslogins
where name like '%pdk%'
OPEN curName
WHILE 1=1
BEGIN
FETCH NEXT FROM curName INTO @username
if @@fetch_status <> 0 begin
break
end
set @sql = 'USE [?]; IF EXISTS(SELECT * FROM sys.database_principals WHERE name = ''' + @username + ''') DROP USER ' + @username
print @sql
EXEC sp_msforeachdb @sql
set @sql = 'drop login ' + @username
print @sql
exec (@sql )
END
CLOSE curName
DEALLOCATE curName
--select * from sys.databases