Intestinal colonization with oxalobacter formigenes and its relation to urinary oxalate excretion in pediat-ric urolithiasis with idiopathic calcium oxalate

Objective To study the colonization with oxalobacter formigenes in pediatric urolithiasis and the relationship with 24 h urinary oxalate excretion. Methods The presence of oxalobacter formigenes stool samples of 20 children and adolescents(aged 2- 18 years) with idiopathic calcium urolithiasis was assessed using polymerase chain reaction(PCR)method.Twenty healthy,age- and sex- matched subjects served as controls.Simultaneously, urinary oxalate excretion was measured by ion chromatography in this group. Results Oxalobacter formigenes was found in 6/20 patients (30%).In controls, frequency of colonization had no statistically significant difference(40%,P> 0.05).The 24 h urinary oxalate excretion in patients colonized with oxalobacter formigenes was significantly lower than in non- colonized patients[(0.79±0.29) mmol/(kg·24 h) vs.(1.16±0.32) mmol/(kg·24 h),P< 0.05]. Conclusion Higher urinary oxalate excretion in children with calcium urolithiasis may be a result of the absence of oxalobacter formigenes. Key words: Oxalobacter formigenes; Idiopathic calcium urolithiasis; Children