I think you can use MacConkey Agar for Enterobacteriaceae, Acinetobacter, Enterococcus, Pseudomonas and Blood Agar for Staph. aureus. Mueller Hinton Agar is better than TSA as Pseudomonas will give pigment to it. 

You can use both chocolate agar and SDA plates (settle plate method). This method is good and reproducible, though it is qualitative.

I'm just going to throw the phrase "metagenomics" out there.  The best way to know who's there is to not bias them with culturing at all...  Extract environmental DNA, amplify exactly what you want with selective PCR primers. 

Hello everyone. First of all, thank you very much for your contributions to answer my question.

Since we want to document the overall contamination along with the prevalence of S. aureus/MRSA and Enterobacteriaceae on surfaces in the ambulance environment, we have decided to test the applicability of RODAC agar with TSA against the aplicability of Dipslides with PCA agar, Baird parker and VRBG. 

Best regards Heidi.

Would you be so kind as to publish your results?

You also may find guidance at Hospital Microbiome Project.

Thank you Thomas, I will look in to it, and do my very best getting the results published.

I have nothing to disclose in this endorsement but I strongly suggest that you contact Ron Brown, M.D. to discuss this topic. He is a World renowned expert on the decontamination of emergency vehicles and equipment. Kindest regards, Tom

http://www.aeroclave.com/

http://www.aeroclave.com/docs/Combating_the_invisible_threat.pdf