Severe lower limb infection by Kerstersia gyiorum: clinical and genomic insights into an underestimated pathogen.

Since Kerstersia gyiorum was first described and named in 2003, reports of human infections caused by this organism have gradually increased. Here, we present a detailed report of a severe case of lower right limb infection caused by K. gyiorum that was characterized by rapid disease progression and multidrug resistance. We also present the complete genome sequence of the isolate, WCHKG1. A systematic analysis of the clinical features of our case patient and previous K. gyiorum-infected patients revealed that the most common site of infection was the lungs (48%), and that the organism showed the lowest sensitivity to commonly used quinolones among the major antibiotic classes. Clinical infections caused by K. gyiorum may be underestimated, thus the use of quinolones in treating such infections should be avoided. Genomic and phylogenetic analyses of K. gyiorum identified conservation of antibiotic efflux pump systems and virulence factors, which may play critical roles in its antibiotic resistance and pathogenicity. Furthermore, evidence of clonal transmission in animals suggests a need for vigilance regarding potential clonal spread in clinical settings. Our study contributes to the current understanding of K. gyiorum and offers useful insights to support its clinical management and infection control.