Innate immune responses triggered by hypermucoviscous carbapenem-resistant Klebsiella pneumoniae ST25 strains in bronchial epithelial cells and alveolar macrophages

RAYA TONETTI, FERNANDA; FUKUYAMA, KOHTARO; SERDA, RODRIGO; ELEAN, MARIANO; JURE, MARÍA ÁNGELA; KITAZAWA, HARUKI; JULIO VILLENA

San Luis

Congreso; LXXI Reunión Anual de la Sociedad Argentina de Inmunología (SAI); 2023

Sociedad Argentina de Inmunología

In recent years, an increase in the prevalence of hypermucoviscous carbapenem-resistant Klebsiella pneumoniae (Kp) of the sequence type (ST) 25 was detected in hospitalized patients in Northwest Argentina. Our previous studies have shown that Kp carbapenemase-2 (KPC-2)-producing ST25 strains are endemic in hospitals of Tucuman and are associated with respiratory and systemic infections. Furthermore, studies in mice showed that Kp ST25 strains have different degrees of virulence when infecting the respiratory tract. In this work, the innate immune responses triggered by two K. pneumoniae ST25 strains (LABACER 01 and LABACER 27) in bronchial epithelial cells (BECs) and alveolar macrophages (AMs) were evaluated. For this purpose, porcine BECs (1.8 104 cells) or AMs (105 cells) were challenged with LABACER 01 or LABACER 27 (107 cells). Samples of mRNA were taken before (0h) and 3, 6, 12, and 24 h after Kp challenge, for the evaluation of inflammatory and regulatory cytokines as well as pattern recognition receptors and negative regulators of the TLR signaling. BECs and AMs challenged with LPS were used for comparisons. The stimulation of BECs with LABACER 01 or LABACER27 significantly increased the expression of the negative regulators A20, BCL3, IRAK M, and SIGIRR when compared to the LPS-treated cells (p