Evaluation of Ordering Practices, Microbial Yield, and Clinical Utility of Urinary Stone Cultures

Abstract Urinary stones are a global problem. While it has been established that microorganisms can be associated with urinary stone formation, data on best practices for microbial culture and clinical interpretation of specimens limited. Our objective was to investigate the present in cultures (usc) companion urine cultures. We conducted retrospective study at tertiry hospital examining submitted between October 2018 2021. collected from electronic medical records patients who had least one usc performed. As part routine workup, all were ground using disposable tissue grinder inoculated tryptic soy agar 5% sheep blood plate (BAP), chocolate (CHOC), MacConkey (MAC), streaked isolation incubated CO2 35°C up three days. Urine performed Kiestra TLA system 10 µL inoculum onto each BAP MAC, plates examined 16 24 hours incubation. For straight or “in out” catheter, 10,000 CFU/mL threshold workup. From clean-voided, midstream, ileostomy, nephrostomy, indwelling/Foley catheter specimens, 100,000 The final significance is determined by evaluating result light patient’s presentation. cultures, clinically insignificant growth considered no when pathogens recovered culture. more than 3 species over contaminated. A total 1,049 854 (55.3% female). median patient age 61 years (IQR 49-70). most frequent reported Proteus mirabilis (N=98), Enterococcus faecalis (N=75), Escherichia coli (N=73). No pathogen identified 57% usc. 441 context (+/-2 days) 336 (39.3%) patients. In addition, 138 (16.1%) 1 usc, being maximum as 11 patient. common urine/USC concordant 165 (37.4%), followed coagulase negative Staphylococcus. Cohen’s kappa obtained results 0.45, which not minimum acceptable agreement. 43% cases. Usc rarely resulted results, but Additional studies warranted evaluate impact care, including antimicrobial use correlation microbes isolated chemical composition.