Mp63-16 Bacteria Promotes Calcium Oxalate Crystal Aggregation Through Biofilm Formation

You have accessJournal of UrologyStone Disease: Basic Research & Pathophysiology (MP63)1 May 2024MP63-16 BACTERIA PROMOTES CALCIUM OXALATE CRYSTAL AGGREGATION THROUGH BIOFILM FORMATION Jeffrey Doeve, Daniel Massana Roquero, Grace H. Holton, Kathleen Mach, and Joseph Liao Jeffrey DoeveJeffrey Doeve , Daniel Massana RoqueroDaniel Massana Roquero , Grace H. HoltonGrace H. Holton , Kathleen MachKathleen Mach , and Joseph LiaoJoseph Liao View All Author Informationhttps://doi.org/10.1097/01.JU.0001009436.52988.91.16AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Common kidney stone types include calcium, uric acid, and struvite. While the association of struvite stones with urea-splitting bacteria is well established, urinary tract infections and bacteriuria also commonly occur with calcium stones, yet the potential etiologic role of uropathogens in calcium stone formation is not well understood. Bacterial biofilms, which are 3D clusters of bacteria surrounded by a self-produced polymeric matrix, may facilitate this stone formation. The objective of this study is to investigate the association of uropathogens on the formation and aggregation of calcium oxalate (CaOx) crystals in an in vitro model. METHODS: CaOx crystals were grown in vitro in a hyperoxaluric solution (pH 6, 5 mM CaCl2, 0.5 mM NaC2O4, aq.) for 24 hours. Crystals were grown in the presence of common uropathogens including E. coli, E. faecalis, K. pneumoniae, P. aeruginosa, and S. aureus. DNase was used for degradation of extracellular DNA, which is a key constituent of the biofilm matrix. Crystal aggregates were imaged via optical, fluorescent, and scanning electron microscopy (SEM) to assess CaOx aggregation and biofilm distribution. An aggregation mass index based on crystal size, aggregate size, and aggregate numbers was used to compare and quantify aggregation in different experimental groups. RESULTS: CaOx aggregation mass index significantly increased in the presence of bacteria, independent of species. SEM showed that bacteria were localized within the CaOx aggregates (Figure 1A). Additionally, the presence of extracellular DNA, that confirms biofilm presence within the aggregates, was confirmed via fluorescence microscopy. The potential role of the biofilm was further confirmed with 48% reduction of the aggregation index in the presence of DNase (Figure 1B). CONCLUSIONS: The combination of hyperoxaluria and uropathogens significantly increased CaOx crystal aggregation. We demonstrated that bacteria can bind to CaOx crystals and induce aggregation through biofilm formation. While additional in vivo experiments are needed, we speculate that bacteriuria may play a role in the formation and growth of calcium stone in patients with supersaturated urine. Download PPT Source of Funding: Funding was received from NIH R21 DK131776 (JCL) and NIH R25 DK122957 (JKD, JCL) © 2024 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 211Issue 5SMay 2024Page: e1037 Advertisement Copyright & Permissions© 2024 by American Urological Association Education and Research, Inc.Metrics Author Information Jeffrey Doeve More articles by this author Daniel Massana Roquero More articles by this author Grace H. Holton More articles by this author Kathleen Mach More articles by this author Joseph Liao More articles by this author Expand All Advertisement PDF downloadLoading ...