Host defense against the infection of Klebsiella pneumoniae: New strategy to kill the bacterium in the era of antibiotics?

Klebsiella pneumonia e ( K. pneumoniae ) is a typical gram-negative iatrogenic bacterium that often causes bacteremia, pneumonia and urinary tract infection particularly among those with low immunity. Although antibiotics is the cornerstone of anti-infections, the clinical efficacy of β-lactamase and carbapenems drugs has been weakened due to the emergence of drug-resistant K. pneumoniae . Recent studies have demonstrated that host defense plays a critical role in killing K. pneumoniae . Here, we summarize our current understanding of host immunity mechanisms against K. pneumoniae , including mechanical barrier, innate immune cells, cellular immunity and humoral immunity, providing a theoretical basis and the new strategy for the clinical treatment of K. pneumoniae through improving host immunity.