Pathogen distribution and risk factors of positive stone culture for patients with upper urinary tract stone

Upper urinary tract stones are often complicated by perioperative infections. Bacterial culture analysis of calculi can reveal pathogen distribution on stone surfaces and help identify risk factors for positive culture outcomes, aiding in infection control.

A retrospective analysis was conducted on 173 patients with upper urinary tract stones who underwent holmium laser lithotripsy. Clinical characteristics potentially influencing positive stone cultures were collected and used to establish a binary logistic regression model for identifying risk factors. Additionally, the correlation between positive stone cultures and postoperative infection markers was analyzed.

Among the 173 patients, 44 had positive stone cultures, and 47 pathogen strains were detected. Forty-six patients had positive urine cultures, with 49 pathogen strains identified. The main pathogens in stone cultures were Escherichia coli (22 strains, 46.81%), Proteus mirabilis (5 strains, 10.64%), Pseudomonas aeruginosa (4 strains, 8.51%), and Klebsiella pneumoniae (3 strains, 6.38%). In urine culture, the main pathogens were Escherichia coli (26 strains, 53.06%), Klebsiella pneumoniae (5 strains, 10.2%), and Acinetobacter baumannii (4 strains, 8.16%). Binary logistic regression identified the following risk factors for positive stone cultures: positive urine white blood cells (OR = 2.881, 95% CI = 1.070-7.760, P = 0.036), hydronephrosis (OR = 5.644, 95% CI = 2.168-14.696, P < 0.0001), struvite stones (OR = 7.512, 95% CI = 1.864-30.283, P = 0.005), and a history of diabetes (OR = 6.580, 95% CI = 1.820-23.791, P = 0.004). Spearman correlation analysis showed a strong correlation between positive stone cultures and postoperative fever (r = 0.666) and CRP failure to return to normal 48 hours post-surgery (r = 0.633), both of which were higher than the correlation with urine bacterial culture.

Escherichia coli is the predominant pathogen in stone cultures. Risk factors for positive cultures include positive urine leukocytes, hydronephrosis, struvite stones, and a history of diabetes. Positive stone cultures are associated with a higher risk of postoperative infection compared to positive urine cultures.