NCT06822465 · University of Chicago
Pathobiomes in Gut of Critically Ill Patients
What this study is about
Despite powerful antibiotics, 50% of the intestinal tracts of critically ill surgical patients are colonized by Pseudomonas aeruginosa, whose mere presence in this site increases mortality fourfold by mechanisms that remain unknown. Many patients who survive the initial surgical trauma still succumb to multi-organ failure and septicemia secondary to an invasive nosocomial infection.
View original scientific description
Despite powerful antibiotics, 50% of the intestinal tracts of critically ill surgical patients are colonized by Pseudomonas aeruginosa, whose mere presence in this site increases mortality fourfold by mechanisms that remain unknown. Many patients who survive the initial surgical trauma still succumb to multi-organ failure and septicemia secondary to an invasive nosocomial infection. The sequelae of shock, hypoxia, and parental nutrition result in injury to the intestinal mucosa, changes in gut permeability, and failure of intestinal defense mechanisms. These conditions put patients at risk for infection and multiple organ failure secondary to the translocation of enteric bacteria, initiating a systemic release of inflammatory mediators-a process that has been termed gut-derived sepsis. Intestinal P. aeruginosa senses host factors released during stress and responds by activating its virulence gene machinery. As such, the presence of a highly activating intestinal milieu serves to induce virulence in strains of P. aeruginosa and this correlates to the severity of a patient's illness. While the host-pathogen interaction is a dynamic process, the study expects that as a patient's illness worsens or resolves over time, the "virulence-activating" properties of their intestinal milieu will change accordingly. This study will conduct a prospective observational trial in a population of critically ill patients at the Universtiy of Chicago Medical Center. This trial will entail collecting and screening stool samples obtained from critically ill patients for their virulence inducing capabilities on laboratory strains of P. aeruginosa using in vitro and in vivo assays. The study also plans to isolate strains of intestinal P. aeruginosa from stool samples to determine the prevalence of intestinal P. aeruginosa in a population of critically ill patients.
Interventions
OTHER
P. aeruginosa using in vitro and in vivo assays
This trial will entail collecting and screening stool samples obtained from critically ill patients for their virulence inducing capabilities on laboratory strains of P. aeruginosa using in vitro and in vivo assays. The investigators also plan to isolate strains of intestinal P. aeruginosa from stool samples to determine the prevalence of intestinal P. aeruginosa in a population of critically ill patients.
Primary outcome measures
In vitro pyocyanin screening assay to determine if a stool sample has any virulence inducing ability on laboratory strains of P. aeruginosa
Time frame: Through study completion, an average of 3 years
In vivo C. elegans lethality model to determine if liquid media culture "spiked" with stool sample filtrate will induce a lethal phenotype in laboratory strains of P. aeruginosa
Time frame: Through study completion, an average of 3 years
PCR array analysis of known P. aeruginosa virulence genes following exposure to stool sample filtrate deemed to be highly activating by the in vitro pyocyanin assay and in vivo C. elegans lethality model.
Time frame: Through study completion, an average of 3 years
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Any ethnicity
- Age \> 18 years and \< 85 years
Exclusion criteria
- A known history of HIV/AIDS
- Active pregnancy
- Are incarcerated will be excluded from the study.
Where
- Hyde Park, Illinois
Collaborators
National Institutes of Health (NIH), National Institute of General Medical Sciences (NIGMS)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 2, 2026 · Source of record for eligibility and locations