Discussion

As ASPs continue to evolve and become central to promoting appropriate antimicrobial use, increased emphasis has been placed on enhancing microbiology reporting to influence prescribing and to supplement active ASP efforts. Culture or organism-specific comments serve as a passive mode of provider education. Wording of such comments, when concise and informative, allows for the evolution of noninvasive stewardship when direct contact is not required to influence prescribing, and it likely provides a durable education mechanism.

To our knowledge, this is the first study to specifically evaluate the effect of templated comments for hospitalized patients with candiduria. We detected a 14.1% decrease in antifungal prescribing for patients with candiduria by leveraging passive microbiology comments, further supporting a growing body of research for embedding templated microbiology comments as a useful strategy to improve antimicrobial stewardship. Once a culture shows growth, there may be a natural inclination to treat (if not already); therefore, we targeted antifungal administration within 72 hours of the results becoming available, allowing providers ample time to evaluate culture results and determine need for treatment. Furthermore, the net effect of the comment(s) may be greater; we evaluated their effect in the period immediately after implementation. Despite a few baseline characteristics being higher in the postimplementation group, the primary outcome remained significant even after adjusting for select differences. Importantly, the comparator groups represented the same calendar periods to minimize any seasonal variance or other unintended confounders.

We did not detect any differences in secondary outcomes between groups. For patients receiving antifungal treatment, there was not a significant difference in antifungal duration, though the postimplementation group had 1 less day of exposure. Regarding concerns for the need to add antifungal therapy later in a case when the templated comment incorrectly nudged providers, we found no statistical difference in antifungal administration rates 73–240 hours after cultures resulted. This finding suggests that the comment did not increase the risk of inappropriate treatment decisions secondary to the nudge.

Preceding work in this area has influenced a trend to incorporate templated comments as a stewardship tactic. In a quasi-experimental study, Musgrove et al ^{Reference Musgrove, Kenney and Kendall3} evaluated the effect of comments on respiratory cultures. For cultures that grew only normal respiratory flora, they added comments regarding the absence of Pseudomonas aeruginosa or Staphylococcus aureus, resulting in a higher rate of broad-spectrum antibiotic de-escalation (39% vs 73%; P < .01) and a 5.5-fold increased odds of antibiotic de-escalation for pneumonia after adjusting for severity of illness and baseline comorbidities. ^{Reference Musgrove, Kenney and Kendall3} The same group recently published a follow-up study demonstrating that the intervention resulted in a durable stewardship practice. ^{Reference Kaur, Hutton and Kenny17} A review by Langford et al ^{Reference Langford, Leung and Haj8} highlighted a more global assessment of various nudging tactics that which can be used to influence antimicrobial prescribing for a number of infectious sources, including urinary. We focused on a different subset of patients, those with urinary growth of Candida, which is frequently associated with colonization rather than infection. Similar to previous studies, we also detected a significant reduction in antifungal prescribing using passive culture-embedded guidance. Cumulatively, the works by Musgrove et al, ^{Reference Musgrove, Kenney and Kendall3} our study results, and previous work regarding nudging principles support the use of templated comments as an effective antimicrobial stewardship tool for a variety of infectious diseases.

This study had several limitations. First, as previously highlighted, we evaluated the intervention immediately after implementation, which may have minimized the true effect of the templated comments without a phase-in adoption period. A lag period in the postintervention group analysis to allow for providers to become acclimated to practice changes may be important in future study designs. Another limitation is the reliance on manual templated comment entry by microbiology laboratory technicians, which may have been a source of inconsistency in the postintervention group. Nevertheless, the postimplementation group contained all patients with candiduria, regardless of comment placement, to ensure consistency among groups. Since these data were collected, the study site has shifted to automating the addition of templated comments by the laboratory software, a process we endorse to ensure consistency for those wishing to replicate this practice. Importantly, this comment exists for both inpatient and outpatient cultures with Candida growth, representing an unassessed cohort who may also benefit from such stewardship interventions. Another limitation was the evaluation of symptomatic disease. Our goal was to evaluate the effect of the intervention on antifungal exposure; therefore, symptomatic versus asymptomatic candiduria was not assessed. Next, the secondary outcome of administration of antifungal use within 73–240 hours is not a validated method to assess safety but represents a window of time when treatment would be initiated should patients decline when treatment was initially withheld. Also, we did not evaluate the need for treatment at the time of microbiology results or the following 30 days after the initial culture results, representing an opportunity for future studies. However, only 1 patient from the postimplementation group had a second urine culture drawn that grew Candida and was treated with an antifungal the day after the result. Also, baseline rates of acute kidney injuries were higher in the postimplementation group, which may have resulted in more patients being treated due to increased concerns for active infection. Despite this increase, the primary outcome remained significantly different when controlling for this along with other significant baseline differences. Finally, although an interrupted time-series design could have been considered, we evaluated the practice change during the same period, 1 year apart, and immediately after implementation. Additionally, no other ASP efforts were undertaken to identify these patients; thus, the quasi-experimental design should have accurately characterized practice change given the large (14.1%) change in a single year.

Our study results provide further evidence supporting the use of templated microbiology comments to improve antimicrobial stewardship. These results also show that candiduria is another important target for passive improvement of responsible antimicrobial prescribing and that using templated comments in urine culture microbiology results lead to reduced antifungal exposure.