This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Urea splitting urinary bacteria

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Bacterial urease generates ammonia from urea, elevating the pH of urine (ie producing alkaline urine). Urinary tract pathogens that produce urease are called urea splitting or urea producing urinary bacteria:

  • examples of urease producing (urea splitting) bacteria include Proteus mirabilis and some Klebsiella species

    • as the pH of urine rises, crystals of calcium and magnesium phosphates come out of solution
    • urease producing bacteria are associated with the incidence of staghorn calculi
      • staghorn calculi are upper urinary tract stones that involve the renal pelvis and extend into at least 2 calyces
        • all types of urinary stones can potentially form staghorn calculi but approximately 75% are composed of a struvite-carbonate-apatite matrix (so-called struvite stones)
        • two conditions must coexist for the formation of struvite calculi
          • alkaline urine (pH >7.2) and
          • the presence of ammonia in the urine
          • these two factors lead to magnesium ammonium phosphate and carbonate apatite crystallization

Urease - producing bacteria are also a concern because of the higher incidence of blocked urinary catheters that occur if there are urease- producing bacteria

  • a study of the ability of 12 urease-positive species of urinary tract pathogens to encrust and block catheters was undertaken
    • Proteus mirabilis, Proteus vulgaris and Providencia rettgeri were able to raise the urinary pH above 8.3 and produce catheter-blocking crystalline biofilms within 40 h

    • Morganella morganii and Staphylococcus aureus elevated the pH of urine to 7.4 and 6.9, respectively, and caused some crystal deposition in the biofilms but did not block catheters in the 96 h experimental period

    • Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Serratia marcescens, Pseudomonas aeruginosa and Providencia stuartii were only capable of raising the pH of urine to a maximum of 6.4 and failed to cause crystal deposition in the biofilm

    • most effective way to prevent catheter encrustation was shown to be diluting urine and increasing its citrate concentration
      • strategy raises the nucleation pH (pHn) at which calcium and magnesium phosphates crystallize from urine
      • increasing the fluid intake of a healthy volunteer with citrated drinks resulted in urine with a pHn of >8.0 in which catheter encrustation was inhibited

Reference:


Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

Connect

Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.