How can we track prepare statement leak on MySQL 5.5

On one of our production servers, we are suspecting prepare statement leak. This instance is used my more than 100 customers each having individual database. So, on MySQL 5.5 how can we trace who is causing the leak. I think on MySQL 5.6 we can use performance_schema to do so. But other than using general queries is there a way to trace it in 5.5 ?

With Regards