Another alternative would be to have MySQL format the DATETIME value as a string in the desired format, using the DATE_FORMAT function.
SELECT DATE_FORMAT(`DateTime`,'%d/%m/%y - %H:%i') AS `DateTime`
...
No change required to your PHP code except for the SQL text sent to the database server.
This approach can very efficient, and reduce the amount of code you need, if all you are doing with this string is displaying it. If you are doing any sort of manipulation on this value, then casting the string value returned from MySQL resultset into a datetime object is probably a better way to go.
A demonstration of the DATE_FORMAT function:
SELECT DATE_FORMAT('2013-02-07 22:14:56','%d/%m/%y - %H:%i') AS `DateTime`
DateTime
----------------
07/02/13 - 22:14