title: Intestinal colonization with Oxalobacter formigenes and its relation to urinary oxalate excretion in pediatric patients with idiopathic calcium urolithiasis.
abstract: OBJECTIVE
  Oxalobacter formigenes is an intestinal bacterium that utilizes oxalate as the only source of energy. It has been suggested that the lack of colonization with this organism may be a risk factor for calcium oxalate urolithiasis. Because this problem was not investigated in pediatric stone formers, we decided to assess it in our patients.
  
  
  METHODS
  The presence of O. formigenes in stool samples of 76 children and adolescents (aged 4.1-18 years) with idiopathic calcium urolithiasis (36 with chemically confirmed calcium oxalate stones and 40 children with a strong clinical suspicion of this type of urolithiasis) was assessed using PCR method. Simultaneously, urinary oxalate excretion was measured in this group. Fifty healthy, age- and sex-matched subjects served as controls.
  
  
  RESULTS
  O. formigenes was found in 21/76 patients (27.6%). In controls, frequency of colonization was similar (26%). The median 24h urinary oxalate excretion in patients colonized with O. formigenes was significantly lower in comparison with non-colonized patients, 0.319 (range 0.141-0.546) and 0.437 (range 0.198-0.967) mmol/1.73 m(2)/24h, respectively.
  
  
  CONCLUSIONS
  Higher urinary oxalate excretion in children with calcium urolithiasis may be a result of the absence of O. formigenes. The reasons for similarly low intestinal colonization with this bacterium in normal subjects and stone formers remain speculative. Thus, further studies are necessary to clarify this issue.
authors.affiliation: Department of Pediatric Nephrology, Medical University of Lublin, Lublin, Poland. sikoraprzem@hotmail.com
authors.forename: Przemysław
authors.initials: P
authors.lastname: Sikora
authors.forename: Justyna
authors.initials: J
authors.lastname: Niedźwiadek
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Mazur
authors.forename: Jolanta
authors.initials: J
authors.lastname: Paluch-Oleś
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Zajaczkowska
authors.forename: Maria
authors.initials: M
authors.lastname: Kozioł-Montewka
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000382:microbiology*; D008297:Male; D010070:Oxalates / Q000378:metabolism* / Q000652:urine; D020624:Oxalobacter formigenes / Q000378:metabolism*; D052878:Urolithiasis / Q000378:metabolism / Q000382:microbiology* / Q000652:urine
chemical_list: D010070:Oxalates