Functional characterization of a novel Mn2+ dependent protein serine/threonine kinase KpnK, produced by Klebsiella pneumoniae strain MGH78578

► KpnK is a novel Ser/Thr kinase produced by multidrug resistant Klebsiella pneumoniae strain. ► KpnK regulates K. pneumoniae growth and response to oxidative and gastric stresses. ► Deletion of kpnK increases K. pneumoniae susceptibility to β-lactam antibiotics. ► The periplasmic and outer membrane stress regulator CpxRKP binds to the kpnK promoter. ► Prokaryotic ESTKs may represent novel targets for antibiotic strategies.