Determination of Intracellular ATP Concentration

Intracellular ATP concentration was measured using the Promega BacTiter-Glo Microbial Cell Viability Assay according to manufacturer’s instructions. Late exponential phase cultures were filtered through a 5 μM filter to remove C. albicans. The remaining S. aureus cells were pelleted and washed with 1% NaCl prior to measuring luminescence. A sample was also taken for serial dilution and enumeration of bacteria. Luminescence was divided by surviving cells to account for any growth differences. Six replicates were used for obtaining averages and standard deviation. Significance was determined using a student’s t-test, P ≤ 0.05.