Coexistence of polymicrobial organisms acted as biofilm communities has become more and more prominent that these interactions lead to an increased resistance against host immune responses and antimicrobial agents, especially bacterial-fungal interactions. Klebsiella pneumoniae and Candida albicans are one of the interesting candidates acted as interkingdom biofilms. K. pneumoniae and C. albicans (KP+CA) presented the interkingdom biofilms with synergistic interaction through molecular analysis and confocal fluorescent imaging with z-stack thickness in vitro experiments. Both of an acute pneumonia model and in vitro neutrophil responses demonstrated that K. pneumoniae infection performed the highest severity when compared to mixed K. pneumoniae and C. albicans and alone C. albicans infections through various biomarkers and the responsiveness of neutrophils. Consequently, this study indicated that polymicrobial with bacterial-Candida infection may less severe than single-bacterial infection.