**9. Conclusions**

As addressed here, EVs transport various types of biomolecules that have been reportedly associated with bacterial survival and host-pathogen interactions. *S. aureus* is, to date, one of the best-documented bacteria in this field. Yet, several research questions remain to be elucidated. First, EVs biogenesis is still poorly understood in Gram-positive bacteria even though recent studies showed *S. aureus*-EVs biogenesis can be affected by a range of intrinsic and external factors, such as PSMs, autolysins, and environmental conditions, such as antibiotics. *Extracellular Vesicles and Their Role in* Staphylococcus aureus *Resistance and Virulence DOI: http://dx.doi.org/10.5772/intechopen.96023*

Moreover, several studies evidenced that selective cargo sorting exist. Since the EV cargo determines their biological functions, clarifying which components are selected, and how, is of crucial value to understand their role in pathogenesis, and to their use as delivery systems. Second, most studies on *S. aureus* EVs have focused on proteomes. As well as proteins, nucleic acid cargo could play essential roles in *S. aureus* survival and pathogenesis. They could be associated to horizontal gene transfer for antibiotic resistance, and regulation of host cell expression by small regulatory RNAs. Therefore, more research is necessary in this field. Third, the physiological role of *S. aureus* EVs remains elusive. Staphylococcal EV cargo was shown to induce host cell toxicity, and skin and pulmonary inflammations, however, to the best of our knowledge, the exact contribution of EVs during infection remains unclear. The study of EV-free *S. aureus* strains in the infection context could reveal valuable clues to their real contribution to pathogenesis. Nevertheless, to the present, this phenomenon is unknown. Finally, their ability to induce a host immune response has arisen interest in using EVs as vehicles for vaccination. Several studies reported that administration of *S. aureus* EVs induce protection against systemic, pulmonary, and cutaneous infections. Although being a recent field of study, these promising data sheds light onto the possible application of engineered EVs to prevent diseases caused by this important human pathogen.
