KLEBSIELLA PNEUMONIAE AFFECTS NEUTROPHIL ELASTASE DYNAMICS

BIRNBERG WEISS, F; PITTALUGA, J; CASTRO, J E; CASTILLO, L; MARTIRE GRECO, D; FEDERICO FUENTES; BIGI, F; GÓMEZ, S; LANDONI, V; FERNANDEZ, G

Mar del Plata

Congreso; LXVII reunión anual de la sociedad argentina de investigación clínica (SAIC). LXX reunión anual de la sociedad argentina de inmunología (SAI) y 3er congreso franco-argentino de inmunología (FAIC). Reunión anual 2022 de la sociedad argentina de fisiología; 2022

The importance of neutrophil elastase (NE) in the bactericidal responseof neutrophils (PMN) relies on different mechanisms. NEcontained in azurophilic granules (AzG) can kill bacteria after fusionwith phagosomes. Also, NE translocation from AzG to the nucleusis a key step for neutrophil-extracellular-traps (NET) formation, anddepends on NE activity. Klebsiella pneumoniae carbapenemase(Kp)-producing bacteria are associated with significant mortality inimmunocompromised patients. We have previously reported thatPMN failed to release NET when challenged with Kp, whereas Escherichiacoli (Eco) was a high NET inducer. Our aim was to deepenthe study of the lack of NET formation in the presence of Kp focusingon NE dynamics. To determine whether Kp directly affects NE activity,we used a PMN lysate as a source of NE, and determined NEactivity using a commercial kit after 1 h incubation with Kp or Eco.We found that neither Kp or Eco affected NE activity (p