Antimicrobial Stewardship Effects of Interpretive Comments for Faecal PCR Tests

July 8, 2026 updated by: Medical Research Institute of New Zealand

Bacterial gastroenteritis is a common condition seen in Aotearoa New Zealand, which is typically diagnosed by PCR testing on a stool sample. Most causes of bacterial gastroenteritis (e.g. Campylobacter spp, Salmonella spp, Yersinia spp) cause a self-limiting illness and antibiotic therapy is not required. Indeed, guidelines available for community healthcare providers in Aotearoa (e.g. Community HealthPathways, recently released national antimicrobial guidelines Te Whata Kura) recommend against antibiotic therapy for the vast majority of cases.

A recent internal analysis at Awanui Laboratories of community faecal pathogen PCR testing revealed that antibiotic prescribing was very common after a positive result (ranging between 20-40% for the various individual pathogens), which suggests many community healthcare providers may not be following the recommended approach for the management of these infections. Given how common infectious gastroenteritis is in Aotearoa, and the volume of tests performed (approximately 100,000 through the Awanui network per year), this prescribing behaviour may represent a large volume of unnecessary antibiotic use in our communities, with resultant potential harmful effects at the individual patient level and population level via side effects, disruption to the faecal microbiome, and impacts on antimicrobial resistance (AMR).

In previous work we have demonstrated that interpretive comments, when added to laboratory reports, can have a significant positive effect on prescriber behaviour (https://doi.org/10.1093/jac/dkad384), but this has not been examined in relation to faecal pathogen testing.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a cluster randomised crossover trial, where four laboratories within the Awanui Labs network in Aotearoa New Zealand will act as the clusters. Each laboratory will be assigned four intervention levels, which will be implemented in random order over the course of the 12 month study period (i.e. 3 months per intervention).

The intervention will consist of interpretive comments that are appended to laboratory reports where a stool sample has been submitted for faecal bacterial pathogen detection (predominantly tested via multiplex PCR methodology) and one of the target organisms has been detected. The target organisms are Campylobacter spp, Shigella spp/Entero-invasive Escherichia coli, Salmonella spp, Yersinia spp, and Aeromonas spp.

There will be four different intervention levels: 1. a comment that reminds requesters that most acute bacterial gastroenteritis does not require antibiotic treatment, as per local guidelines; 2. the same comment as 1 is used, plus an additional comment is added reminding requesters of the negative effects of antibiotic over use at the population level (i.e. AMR); 3. the same comment as 1 is used, plus an additional comment is added reminding requesters of the negative effects of antibiotic overuse at the individual patient level e.g. harms due to side effects; 4. is a the control group, where no comment is appended.

The four levels will be auto added by each lab, each for a three month period, in the random order allocated at the beginning of the study.

Outcome measures will relate to antibiotic use in the time period following the laboratory report, plus unplanned hospitalisation out to 30 days post report.

Study Type

Interventional

Enrollment (Estimated)

10000

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age over six months
  • Stool sample submitted to Awanui Labs for faecal bacterial pathogen testing from a community health provider during the study period
  • Test results report the detection of: Campylobacter spp, Shigella spp/Entero-invasive Escherichia coli, Salmonella spp, Yersinia spp, or Aeromonas spp.

Exclusion Criteria:

  • Samples where only Clostridioides difficile or Helicobacter pylori testing has been requested will be excluded
  • Samples sent for Public Health testing (e.g. testing for clearance of Salmonella spp) will be excluded.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Interpretive laboratory comment - guideline
Interpretive comment with advice to follow local guidelines
Other: Interpretive comment on laboratory report
Interpretive commend added to laboratory report - contents of comment will depend on associated arm
Active Comparator: Interpretive laboratory comment - guideline + population harms
Interpretive comment with advice to follow local guidelines PLUS comment about population level harms of antibiotic overuse (i.e. AMR)
Other: Interpretive comment on laboratory report
Interpretive commend added to laboratory report - contents of comment will depend on associated arm
Active Comparator: Interpretive laboratory comment - guideline + individual harms
Interpretive comment with advice to follow local guidelines PLUS comment about individual patient harms of antibiotic overuse (e.g. side effects)
Other: Interpretive comment on laboratory report
Interpretive commend added to laboratory report - contents of comment will depend on associated arm
No Intervention: Control
No comment added to lab report

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Specific antibacterial dispensing
Time Frame: Within 5 days of lab report
Antibacterial dispensing within 5 days of laboratory report for agents that are more specific for the treatment of bacterial gastroenteritis: amoxicillin, azithromycin, ciprofloxacin, doxycycline, erythromycin, co-trimoxazole
Within 5 days of lab report

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Any antibacterial dispensing
Time Frame: Within 5 days of lab report
Antimicrobial dispensing within 5 days of laboratory report for any antibacterial agent
Within 5 days of lab report
Antibacterial dispensing within 30 days
Time Frame: Within 30 days of lab report

Antimicrobial dispensing within 30 days of laboratory report

  1. For any antibacterial agent
  2. Limited to these agents that are more specific for the treatment of bacterial AG: amoxicillin, azithromycin, ciprofloxacin, doxycycline, erythromycin, co-trimoxazole
Within 30 days of lab report
Unplanned hospital admission
Time Frame: Within 5 and 30 days of lab report.
Unplanned hospital admission within 5 and 30 days of laboratory report
Within 5 and 30 days of lab report.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical Research Institute of New Zealand

Collaborators

Awanui Labs

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 2, 2026

Primary Completion (Estimated)

September 17, 2027

Study Completion (Estimated)

September 17, 2027

Study Registration Dates

First Submitted

July 8, 2026

First Submitted That Met QC Criteria

July 8, 2026

First Posted (Actual)

July 14, 2026

Study Record Updates

Last Update Posted (Actual)

July 14, 2026

Last Update Submitted That Met QC Criteria

July 8, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • FPC2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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