Population Structure, Antibiotic Resistance, and Uropathogenicity of Klebsiella variicola.

is a member of the genus and often misidentified as or The importance of human infections has been known; however, a dearth of relative knowledge exists for Despite its growing clinical importance, comprehensive analyses of population structure and mechanistic investigations of virulence factors and antibiotic resistance genes have not yet been performed. To address this, we utilized , , and methods to study a cohort of isolates and genomes. We found that the population structure has two distant lineages composed of two and 143 genomes, respectively. Ten of 145 genomes harbored carbapenem resistance genes, and 6/145 contained complete virulence operons. While the β-lactam and quinolone antibiotic resistance genes were generally conserved within our institutional cohort, unexpectedly 11 isolates were nonresistant to the β-lactam ampicillin and only one isolate was nonsusceptible to the quinolone ciprofloxacin. isolates have variation in ability to cause urinary tract infections in a newly developed murine model, but importantly a strain had statistically significant higher bladder CFU than the model uropathogenic strain TOP52. Type 1 pilus and genomic identification of altered operon structure were associated with differences in bladder CFU for the tested strains. Nine newly reported types of pilus genes were discovered in the pan-genome, including the first identified P-pilus in spp. Infections caused by antibiotic-resistant bacterial pathogens are a growing public health threat. Understanding of pathogen relatedness and biology is imperative for tracking outbreaks and developing therapeutics. Here, we detail the phylogenetic structure of 145 genomes from different continents. Our results have important clinical ramifications as high-risk antibiotic resistance genes are present in genomes from a variety of geographic locations and as we demonstrate that clinical isolates can establish higher bladder titers than Differential presence of these pilus genes in isolates may indicate adaption for specific environmental niches. Therefore, due to the potential of multidrug resistance and pathogenic efficacy, identification of and to a species level should be performed to optimally improve patient outcomes during infection. This work provides a foundation for our improved understanding of biology and pathogenesis.