Uropathogenic bacteria are widely distributed in the environment and
urinary tract infection is implicated in
kidney stone disease. Here, we report on a
urease negative bacterium Kalamiella piersonii (strain YU22) isolated from the urine of a
struvite stone (MgNH4PO4·6H2O) patient. The closest species, K. piersonii IIIF1SW-P2T was reported from International Space Station samples. However, there are no earlier reports on its human association. Using whole genome and experimental analysis, its involvement in urinary tract colonization and
struvite crystallization was explored. The strain YU22 showed many
virulence factors that are needed for host cell invasion and colonization including
cell adhesion factors, swimming and swarming motilities, biofilm and
siderophore among others. In vitro
infection studies in HEK-293T cells demonstrated the host cell attachment and killing. It was able to utilize
amino acids as sole
carbon source and showed growth in synthetic and healthy urine establishing metabolic adaptation to urinary tract. Increased pH and availability of
ammonium ions from
amino acid breakdown promoted
struvite crystallization. The results from this study support the involvement of
urease negative uropathogen in the
struvite lithogenesis. Further studies on other isolates of K. peirsonii are warranted to assess its health risks.