Real-time quantification of Staphylococcus aureus in liquid medium using infrared thermography

We previously showed that infrared thermography (IRT) could be used to quantify viable Escherichia colt, a representative gram-negative bacterium, in liquid growth media. Here, we evaluated the ability of IRT to enumerate a viable representative gram-positive organism, Staphylococcus aureus. We found that the energy content (EC) of the media was strongly positively correlated (r = 0.999) to measured viable counts of S. aureus ranging from 85 colony-forming units (CFU)/ml to similar to 4 x 10(8) CFU/ml. The EC of S. aureus was similar to 2-fold higher than that of E. colt at comparable cell concentrations suggesting that IRT may be used to distinguish genera. Published by Elsevier B.V.