Table 1.

Contents contained in MVs.

Vesicle types	Outer membrane proteins	Cytoplasmic (or inner) membrane proteins	Plasmids	RNA and chromosomal DNA	Endolysins	Virulence factors	Hydrophobic molecules	Phages
Outer-membrane vesicle (Gram-negative)	+	-(+)	?	-(+)	−	+	+	−
Explosive outer-membrane vesicle (Gram-negative)	+	+	+	+	+	+	+	+
Outer-inner membrane vesicle (Gram-negative)	+	+	+	+	+	+	+	+
Cytoplasmic membrane vesicle (Gram-positive)	NA	+	+	+	+	+	−	+
Tube-shaped membranous structure (Gram-negative)	+	−	−	−	?	−	−	−
Tube-shaped membranous structure (Gram-positive)	NA	−	+	+	?	?	−	−

+, present; −, absent;? unknown; NA, not applicable.