An observational study in Dysbiosis, Clostridium Difficile and Pet-Human Bonding, sponsored by University of Pennsylvania. Active, not recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-09.
Sponsored by University of Pennsylvania · Observational
Antimicrobial therapy can lead to disruption of the gut microbiome and infection with Clostridioides difficile, a disease associated with high morbidity and mortality, particularly among the elderly. Drawing on observations that pet ownership and close contact with pets are protective against colonization with C. difficile and recurrence of C. difficile infection, the proposed study will test the hypothesis that microbiota that provide colonization resistance against C. difficile are shared between patients and their pets and that pet contact can mitigate antimicrobial-associated gut dysbiosis and the risk of C. difficile infection. This study will further define epidemiologic and pathophysiologic characteristics of C. difficile infection and gut microbiome dysbiosis that could enhance therapeutic options for these conditions, potentially through non-invasive interventions involving animal contact.
Clostridioides difficile infection (CDI) is one of the most common causes of healthcare-associated infectious diarrhea and results in significant morbidity and mortality. CDI occurs when the native gut microbiome is disrupted, most often following antimicrobial therapy, and the consequent dysbiosis results in a decrease in microbial diversity, changes in abundance of certain bacterial taxa, and loss of colonization resistance against C. difficile. Restoration of a "functionally intact" gut microbiome is critical to clearing C. difficile, and inadequate restoration can lead to recurrent CDI. The recovery of the gut microbiome from dysbiosis is poorly understood, and factors associated with having and re-gaining a providing colonization resistance against C. difficile are not well known. While animal reservoirs can serve as potential sources of pathogenic bacteria, studies by the candidate and other investigators found that pet ownership protects against colonization and re-infection with C. difficile. Moreover, microbiota are shared between pets and their owners, and the microbiomes of pets contain bacterial taxa that provide colonization resistance against C. difficile. Based on these data, the proposed research will 1) test the hypothesis that the observed protective effects of pet ownership are due to sharing of microbiota that provide colonization resistance against C. difficile between pets and owners; 2) determine whether pet contact mitigates antimicrobial-associated disruption of the gut microbiome and enhances its recovery; and 3) assess whether pet contact decreases the likelihood of colonization and infection with C. difficile following antimicrobial therapy. This will be accomplished though longitudinal sampling of the gut microbiome within the patient/pet unit among patients receiving prophylactic antimicrobials for non-enteric indications (dental implants).
The study will further define epidemiologic and pathophysiologic characteristics of CDI that could enhance therapeutic options for this disease. The underlying premise that animals are a source of protective microbiota rather than a reservoir of C. difficile represents a paradigm shift in CDI epidemiology that may identify animal contact as a novel microbiome-based form of therapy.
187 studies on the registry are indexed under Dysbiosis; 64 are open to participants now.
This study's planned enrollment of 200 is above the median of 82 across 51 observational studies indexed under Dysbiosis.
Browse Dysbiosis studies →University of Pennsylvania is the lead sponsor of 1,668 studies on the registry; 235 are open to participants now.
Of its 158 completed or terminated interventional studies of FDA-regulated products, 109 (69%) have results posted.
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The source population will include patients over 18 years of age receiving prophylactic oral antimicrobials for dental implants at the University of Pennsylvania School of Dental Medicine.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Pet owners
Non pet owners
Longitudinal change in diversity and composition of the gut microbiota following oral antibiotic prophylaxis
Changes in alpha diversity, beta diversity and composition of the gut microbiome will be ascertained between baseline (prior to taking antibiotics) and 3, 10, 30 and 90 days following the start of the antibiotic regimen
Time frame: 90 days
Colonization or infection with C. difficile following antibiotic prophylaxis
The presence of C. difficile in patients' stool will be determined before and 3 days after the beginning of the antibiotic regimen
Time frame: 3 days
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No — Any data, specimens, forms, reports, video recordings, and other records that leave the site will be identified only by a participant identification number (Participant ID, PID) to maintain confidentiality. All records will be kept in a locked file cabinet. All computer entry and networking programs will be done using PIDs only. Information will not be released without written permission of the participant, except as necessary for monitoring by the IRB or NIAID. Any presentation, abstract, or manuscript will be made available for review by the sponsor and the NIAID prior to submission.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is active, not recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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