The pks gene clusters modulate the pathogenicity of Klebsiella pneumoniae by impairing neutrophil extracellular traps

ABSTRACT The pks gene clusters, crucial virulence-associated gene clusters in Klebsiella pneumoniae ( K. pneumoniae ), have been verified to exacerbate disease severity in infected hosts. During the early stage of pks -positive K. pneumoniae infection, neutrophil extracellular traps (NETs) are produced by neutrophils to capture and eliminate pathogens. However, neutrophils struggle to completely eliminate bacteria via NETs. To confirm the role of the pks gene clusters in infection, we performed a bacterial survival assay to assess neutrophil dysfunction. NET structural damage was confirmed via scanning electron microscopy observation and NET staining. The DNA breakage was verified by γH2AX staining and Western blot. In the mouse sepsis model, immunofluorescent staining and histological analysis were used to verify pathogenic changes induced by the pks gene clusters. Data were analyzed using the Mann-Whitney U test or the Kruskal-Wallis H test. Results showed that the pks gene clusters were associated with DNA damage. The pks gene clusters disrupted the mesh-like structure of NETs, which resulted in NET dysfunction. In vivo , pks -positive K. pneumoniae affected the bactericidal capacity of NETs. In the mouse model, pks -positive Klebsiella pneumoniae is more prone to inducing liver abscess formation. In conclusion, the pks gene clusters impair NET function, reducing NETs’ ability to capture and kill bacteria, and increasing the risk of liver abscess formation. IMPORTANCE This study elucidates the interplay between the pks gene clusters of Klebsiella pneumoniae and neutrophil extracellular traps (NETs). Our observations underscore the impact of the pks gene clusters on NETs’ functionality, and we further investigate its implications on murine pathogenicity and virulence. These findings offer novel insights into the clinical management of Klebsiella pneumoniae infections.