This study presents combination of advantages in MEMS technology and molecular methods for detection of methicillin resistant gene, mecA, in Staphylococcus aureus. A disposable MEMS DNA biosensor was designed and fabricated for optical and electrochemical detections. Adsorption of DNA on gold electrode was examined theoretically and experimentally. In theoretical studies, Lennard Jones potential energies of gold and thiol group, and adsorption kinetics of DNA were discussed and, electrochemical analysis of Hoescht 33258 was given. In experimental studies, 27-mer capture and target probes were used to examine the detection of mecA gene. YOYO®-1-iodide nucleic acid stain was used to check adsorption on disposable gold electrodes while Hoescht 33258 was used as a redox marker to amplify signal in electrochemical detection. Experimental results obtained from fluorescence microscopy demonstrate the applicability of hybridization on gold electrodes. Detection of mecA gene electrochemically needs further study.