Quorum sensing in Klebsiella pneumoniae: An interconnected regulatory network driving virulence and antimicrobial resistance

This review provides an integrative analysis of the current knowledge on Klebsiella pneumoniae quorum sensing (QS) network. Although it is widely recognised as a high-priority ESKAPE pathogen, the regulatory networks coordinating its virulence and persistence remain insufficiently understood. Here, we examine QS as regulatory framework linking pathogenicity, including multidrug resistance. We first synthesise the major stages of infection, virulence factors related, and molecular basis of antibiotic resistance and immune evasion. We then focus on the four main QS systems described in K. pneumoniae (AHL-SdiA, AI-2-Lsr complex, QseBC-AI-3, and indole-CpxAR), highlighting their individual roles and potential interactions in controlling virulence-associated phenotypes. Overall, while direct experimental validation remains limited, the available evidence suggests that QS in K. pneumoniae likely functions as a complex and interconnected regulatory network rather than as independent signalling pathways. Understanding how these systems coordinate bacterial behaviour is essential for bridging the gap between genomic data and phenotypic expression. In this context, targeting QS emerges as a promising anti-virulence strategy aimed at disarming the pathogen, potentially reducing selective pressure for resistance and contributing to the development of alternative therapeutic approaches.