Platelets have long been recognized for their role in maintaining the balance between hemostasis and thrombosis. While their contributions to blood clotting have been well established, it has been increasingly evident that their roles extend to both innate and adaptive immune functions during infection and inflammation. In this comprehensive review, we describe the various ways in which platelets interact with different microbes and elicit immune responses either directly, or through modulation of leukocyte behaviors.

Platelets are known for essential activities in hemostasis and for their important contribution to protection against infectious pathogens. Klebsiella pneumoniae is an opportunistic pathogen widely known to cause nosocomial infections. Recently, hypervirulent strains of K. pneumoniae have been emerging, which can cause severe infections in immunocompetent individuals.