Comparative proteomics of different strains Staphylococcus aureus in planktonic and biofilm cultures

Biofilm production represents an important virulence factor for Staphylococcus aureus (S.a). Its presence in the environment of food industry poses a serious risk of food contamination. The mechanism and/or process of biofilm formation in S.a is poorly understood and proteomics studies to understand the species-specific mechanisms of biofilm formation are still missing. The aim of this study was to compare the proteomic profile of the sessile and planktonic form of five different strains of S.a with different biofilm formation index. The experiment was conducted on five strains: S.a ATCC 35556 (strong biofilm producer), S.a ATCC 12600 (moderate biofilm producer), S.a ATCC 29213 (weak biofilm producer),and two S.a wild isolate (strong and moderate biofilm producer). All this strains have been grown both in the planktonic and in the sessile form (biofilm formation) and analyzed through 2D electrophoresis coupled with MALDI-TOF MS. The data analysis have been performed in order to discover the mechanisms of biofilm formation common to all analyzed strains. The differential protein expression highlighted the presence of 17 differentially expressed proteins. Conclusions The different expression of some proteins involved in stress response give new insights the mechanisms behind higher resistance of biofilm conformation to, for example, alcohol-based disinfectants. The discovered pathways could represent useful targets to counteract biofilm formation and to improve food safety.