The Genova CDSA was the test performed for me that identified GI overgrowths of Candida Parapsilosis, Pseudomonas Aeruginosa, Staphylococcus Aureus and group B Streptococcus. it was almost 20 years ago, so I'm sure that the test method has improved, just as DNA science has.
http://www.gdx.net/home/
http://www.gdx.net/product/10006
The Genova site requires a physician to order the test, but there are alternate websites through which the kit can be ordered.