Type of Practice


Asymptomatic bacteriuria (ASB) is the presence of bacteria in urine without symptomatic urinary tract infection. Except during pregnancy, the benefits of antibiotic treatment of asymptomatic bacteriuria are greatly outweighed by the risks (e.g. C. difficile infection). Although as many as 98% of non‐catheter urine specimens submitted for culture in acute care hospitals are from patients with ASB, positive cultures lead to antibiotic treatment in 40‐50% of cases. Many interventions have been tried to reduce treatment of ASB, but they are often not effective, and they have proved very difficult to sustain.

In 2013, a resident trainee conducted a pilot study at SHS in which all patients for whom non‐catheter urines were submitted were assessed for urinary symptoms. The urine cultures were processed, but instead of reporting positive culture results, the laboratory sent a message that ASB should not be treated in patients without urinary symptoms, and that urine culture results, if needed, could be obtained by calling the microbiology laboratory. This resulted in a reduction in treatment of ASB from 44% to 12%.

A working group of nursing, microbiology, medicine, informatics and infection prevention and control worked to develop a system in which non‐catheter urine specimens ordered for microbiology would be received but not processed in the laboratory, unless a clinician called the lab to ask that the specimen be processed. This system required work to ensure the accurate labelling of catheter versus non‐catheter urine specimens, to have the hospital information system automatically change orders for urine specimens being sent from particular units, to create a system for calling the laboratory that was clinician‐friendly but minimized disruption to laboratory workload, and to develop a process for ensuring the safety of patients associated with this change, and to plan communication/education associated with this change in practice.

It was determined that 1200 patients would be required to be followed to be confident that not processing urine specimens was as safe or safer than processing them. In 2014, the initial system was piloted on 2 surgical wards. In 2015, the intervention was expanded to all surgical wards. In 2017, the practice will be extended to include internal medicine units.

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