KLEBSIELLA PNEUMONIAE AFFECTS NEUTROPHIL ELASTASE DYNAMICS

FEDERICO BIRNBERG-WEISS , ; JOSÉ R. PITTALUG1 , ; JOSELYN E. CASTRO ,; LUIS A. CASTILLO , ; DAIANA MARTIRE-GRECO ,; FEDERICO FUENTES; FABIANA BIGI , ; SONIA A. GÓMEZ ; LANDONI, VERÓNICA; GABRIELA C. FERNÁNDEZ

Mar del plata

Congreso; Sociedad Argentina de Inmunologia; 2022

The importance of neutrophil elastase (NE) in the bactericidal response of neutrophils (PMN)relies on different mechanisms. NE contained in azurophilic granules (AzG) can kill bacteriaafter fusion with phagosomes. Also, NE translocation from AzG to the nucleus is a key stepfor neutrophil-extracellular-traps (NET) formation, and depends on NE activity. Klebsiellapneumoniae carbapenemase (Kp)-producing bacteria are associated with significant mortalityin immunocompromised patients. We have previously reported that PMN failed to release NETwhen challenged with Kp, whereas Escherichia coli (Eco) was a high NET inducer. Our aimwas to deepen the study of the lack of NET formation in the presence of Kp focusing on NEdynamics.To determine whether Kp directly affects NE activity, we used a PMN lysate as a source ofNE, and determined NE activity using a commercial kit after 1 h incubation with Kp or Eco. Wefound that neither Kp or Eco affected NE activity (p