title: [A study of urease activity of mouth cavity microflora].
abstract: OBJECTIVE
  Analysis of the prevalence of mouth cavity urealytic microflora and determination of the level of its enzymatic activity depending on concentration and amount of urea solution taken as a substrate.
  
  
  METHODS
  62 randomly chosen patients at the age of 5-64 took part in the study. Each of them rinsed the mouth with 50 ml of 1% urea solution. Before and after rinsing the concentration of ammonia in the mouth cavity air was measured. In patients with highest and lowest activity of mouth cavity urealytic microflora a series of tests was carried out including mouth rinsing with urea solution in various concentrations and amounts and measuring ammonia concentration before and after rinsing. Obtained results were analyzed using mathematical statistics methods.
  
  
  RESULTS
  It was found that in 91% ± 1.8% of randomly chosen patients (p < 0.05) mouth cavity microflora showed apparent urease activity. The lowest concentration (0.0625% in 50 ml) and volume (0.5 ml of 1% solution) levels of urea solution were obtained that can exert negative influence on the results of helicobacteriosis diagnosis by means of mouth cavity air analysis.
  
  
  CONCLUSIONS
  Urealytic microflora in the mouth cavity is very common and may constitute a factor that decreases the specificity of helicobacteriosis diagnosis by means of the methods based on detection of indicators of gas metabolites resulting from the enzymatic reaction in air samples taken from the mouth cavity after oral administration of urea.
authors.forename: S É
authors.initials: SÉ
authors.lastname: Bykov
authors.forename: A S
authors.initials: AS
authors.lastname: Bykov
mesh_terms: D000293:Adolescent; D000328:Adult; D001426:Bacterial Proteins / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000201:enzymology*; D016480:Helicobacter pylori / Q000201:enzymology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000201:enzymology / Q000382:microbiology; D014510:Urease / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D014510:Urease