Use of Peezy device to try to improve quality of urine culture

Background

Urine cultures are often contaminated, making interpretation difficult.

  • Pure growths may often not reflect infection and may be due to contamination - in our lab only one third of pure growths from pregnant women are reproducible. 
  • In pre-op urines mixed growths make optimising prophylactic antibiotics difficult. We often end up giving broad spectrum antibiotics to cover all the organisms in a mixture as there is insufficient time to get a repeat. Alternatively, multi-resistant organisms may not be covered adequately.
  • For patients with bacteraemia from a urinary source, many have a mixture in their urine culture. This compromises early rationalisation of antibiotic therapy.
The Peezy has been designed to try to improve the quality of urine specimens by automatically discarding the beginning and end of the urine sample. In 2018 we trialled its use in pre-operative patients. These are the results.

Number of patients

The Peezy was used for both orthopaedic and urology pre-op urine specimens (our protocol at the time was to screen all orthopaedic patients for gentamicin resistant gram negatives - we no longer screen these patients). The nursing team recorded whether patients were able to use the Peezy or not.


Culture results


Use of the Peezy :
  • increased the rate of negative culture from 115/158 (73%) to 106/123 (86%) 
  • decreased the rate of E coli from 10/158 (6%) to 4/123 (3%)
  • decreased the rate of faecal streps (enterococci) from 6/158 (4%) to 1/123 (1%)
  • decreased the rate of mixed cultures from 20/158 (13%) to 8/123 (7%)
Conclusions

These are not matched populations as patients who were not able to use the Peezy may have different microbiology to those that can.
Nevertheless, this would appear to be a significant change in urine culture results, with potential significant impact on laboratory processing time and the appropriateness of subsequent management.
We need proper controlled trials and cost analysis.






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