Klebsiella pneumoniae outer membrane vesicles induce strong IL-8 expression via NF-κB activation in normal pulmonary bronchial cells

•Klebsiella pneumoniae produces outer membrane vesicles (OMVs) that play a key role in microorganism-host interactions.•HvKp, a hypervirulent strain of K. pneumoniae,the average size of OMVs derived from hvKp is smaller than that of cKP-derived OMVs.•Despite these differences, both hvKp-derived and cKP-derived OMVs induce a similar level of expression of IL-8 mRNA and protein.•OMVs secreted by K. pneumoniae stimulate the secretion of interleukin 8 by activating the nuclear factor NF-κB.