The effect of silicon and polyvinyl chloride as growth substrate on the antibiotic resistance of biofilm associated P. putida was examined under different concentrations of Sulfamethoxazole (0, 10, 100 and 500 µg/mL) using a combination of SEM imaging, light microscopy and Elemental Analysis. The density of biofilm on the surface of the growth substrate, the coverage rate of the surface and the uptake of 15N were observed respectively and examined towards potential differences between the two growth substrates. A slight preference of P. putida towards PVC as growth substrate could be detected, most likely due to the surface characteristic of the material. Biofilms on both materials showed high resistance towards the antibiotic pressure. However, no significant differences in 15N uptake could be detected between both materials, implying a similar cell activity in the biofilms and no significant influence from the material of the growth substrate. Further analysis might be conducted focussing on the examination of different plastic materials and the addition of resistant bacterial strains to enable and monitor cell-to-cell interactions.