Integrated transcriptomic and metabolomic analysis of the global response of Staphylococcus aureus to ohmic heating

Ohmic heating (OH), an alternative thermal processing method, has been widely used for the pasteurization of foods. To further understand the inactivation mechanism on microorganisms and the formation of sublethally injured cells subject to OH treatment, transcriptomic and metabolomic changes of Staphylococcus aureus treated with OH and water bath heating (WB) were characterized. There were 349 and 180 differential genes and metabolites after OH treatment, respectively. Amino acids and their secondary metabolites accounted for the largest proportion of differential metabolites for the two treatments, while the majority of differential metabolites between the two heating methods were lipids. The results indicated that OH led to osmotic imbalance, cell membrane damage and energy metabolism disorder of S. aureus. Meanwhile, replication, transcription and translation were inhibited, virulence factors also decreased after OH treatment. Sublethally injured cells induced by OH required increased energy to maintain osmotic, repair damaged membrane and express selective genes for survival.