To determine the frequency of antimicrobial management changes in response to positive gastrointestinal pathogen multiplex panel (GIP) results in patients with suspected infectious diarrhea, identify predictors of those changes, and assess their guideline adherence.

Single-center, retrospective cohort study

Tertiary referral center, including ambulatory and acute care settings.

Adult and pediatric patients with diarrhea and positive GIP evaluated in emergency department, inpatient, or outpatient settings between January 1 and December 31, 2018, were included. Patients considered immunocompromised due to underlying conditions and/or current/recent immunosuppressive therapies were excluded.

The primary outcome of interest was any change in antimicrobial treatment in response to a positive GIP. The secondary outcome was adherence to pathogen-specific guideline-recommended management. Marginal standardization with logistic regression models was also used to assess predictors of antimicrobial management change.

The analysis included 193 patients with diarrhea and a positive GIP. The most frequently detected pathogens were norovirus, Salmonella, and Campylobacter. The median time from test collection to result was 31 hours [Q1, Q3: 24, 52]. Of the 193 patients, 71 (37%) experienced an antimicrobial management change, 61 of whom (86%) were considered guideline-adherent. In adjusted models, empiric antimicrobial treatment and testing in outpatient settings were significantly associated with experiencing an antimicrobial change.

Around one-third of patients with a positive GIP test experienced a change in antimicrobials, and most of these changes were guideline-adherent. Most GIP tests ordered during the study period were negative, and most positive tests did not require antimicrobial therapy.