An observational study in Healthcare-Associated Infections (HAIs), Carbapenem-Resistant Enterobacteriaceae Colonization and Antimicrobial Resistance (AMR), sponsored by Hospital Italiano de Buenos Aires. Not yet recruiting at 1 site in Argentina. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-06.
Sponsored by Hospital Italiano de Buenos Aires · Observational
Carbapenemase-producing Enterobacterales (CPE) are multidrug-resistant bacteria that can colonize the gastrointestinal tract of hospitalized patients and spread within intensive care units (ICUs). Some colonized individuals may carry a particularly high bacterial burden and contribute disproportionately to environmental contamination and transmission to other patients. Identifying these high-risk individuals could improve infection prevention and control strategies.
This prospective observational study will be conducted in the Adult Intensive Care Unit of Hospital Italiano de Buenos Aires. Patients identified as colonized with CPE through routine surveillance will undergo quantitative culture and real-time polymerase chain reaction (PCR) testing of rectal swabs to measure bacterial load. Environmental samples will also be collected from high-touch surfaces surrounding colonized patients. In selected cases, molecular typing methods will be used to evaluate genetic relatedness between patient and environmental isolates and to investigate possible transmission events.
The primary objective is to determine the correlation between bacterial load measured by culture and the PCR cycle threshold (Ct) value. Secondary objectives include evaluating the association between bacterial load and environmental contamination, and assessing whether patients with higher bacterial loads are more likely to contribute to transmission within the ICU. Results may help identify patients with increased dissemination potential and support targeted infection prevention interventions.
Carbapenemase-producing Enterobacterales (CPE) represent a major global public health threat because of their extensive antimicrobial resistance and their ability to spread within healthcare facilities. Gastrointestinal colonization is recognized as the main reservoir for transmission. Previous studies have suggested that a subset of colonized patients, often referred to as "super-spreaders," carry a substantially higher bacterial burden and may account for a disproportionate share of environmental contamination and transmission events.
Although bacterial load can be quantified using culture-based and molecular methods, there is currently no validated cycle threshold (Ct) value from routinely used real-time PCR assays that reliably identifies patients with high dissemination potential. Establishing a correlation between Ct values and bacterial burden could provide a practical and accessible tool for infection prevention programs.
This prospective observational cohort study will be conducted in the Adult Intensive Care Unit of Hospital Italiano de Buenos Aires. All patients identified through the institutional surveillance program as colonized with CPE will be eligible for inclusion. For each CPE-positive patient, rectal swabs obtained as part of routine surveillance will undergo quantitative culture on selective chromogenic media and molecular testing using real-time PCR targeting carbapenemase genes. Bacterial load will be estimated using colony-forming unit counts and PCR Ct values.
Environmental contamination will be assessed through systematic sampling of high-touch surfaces in the patient's surroundings, including bed linen, bedside furniture, and medical equipment. Environmental isolates will undergo microbiological and molecular characterization. In selected situations, whole genome sequencing or pulsed-field gel electrophoresis will be performed to evaluate genetic relatedness among isolates recovered from patients, environmental samples, and secondary cases.
The primary outcome is the correlation between quantitative bacterial load and PCR Ct values. Secondary outcomes include the extent of environmental contamination associated with different bacterial loads and the occurrence of transmission events involving genetically related strains. Multivariable analyses will evaluate the influence of relevant clinical and epidemiological factors, including length of stay, fecal incontinence, prior antimicrobial exposure, immunosuppression, and other potential confounders.
The study involves minimal risk because all patient samples are obtained within the framework of routine infection control surveillance. Findings from this study may improve the identification of patients with increased transmission potential and support more targeted and efficient infection prevention strategies in critical care settings.
285 studies on the registry are indexed under Cross Infection; 48 are open to participants now.
This study's planned enrollment of 60 is below the median of 351 across 115 observational studies indexed under Cross Infection.
Browse Cross Infection studies →Hospital Italiano de Buenos Aires is the lead sponsor of 133 studies on the registry; 24 are open to participants now.
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Adult patients hospitalized in the Adult Intensive Care Unit of Hospital Italiano de Buenos Aires during the study period, with a positive surveillance rectal swab for carbapenemase-producing Enterobacterales detected through the institutional infection control surveillance program.
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Exclusion Criteria
-Patients colonized or infected with carbapenemase-producing Enterobacterales who remained in the same room for less than 48 hours.
Patients admitted to the Adult Intensive Care Unit of Hospital Italiano de Buenos Aires with a positive surveillance rectal swab for carbapenemase-producing Enterobacterales (CPE). Participants will undergo quantitative culture and real-time PCR testing of rectal swabs as part of routine surveillance. Environmental samples will be collected from high-touch surfaces surrounding colonized patients to evaluate environmental contamination and transmission dynamics.
Correlation Between PCR Cycle Threshold (Ct) Value and Quantitative Bacterial Load (CFU/swab) in Rectal Surveillance Swabs
Spearman correlation coefficient between the cycle threshold (Ct) value obtained by real-time PCR (BD MAX™ system) targeting carbapenemase genes and the quantitative bacterial load measured by culture on CHROMagar™ KPC selective medium, expressed as colony-forming units per swab (CFU/swab), from rectal surveillance swabs positive for carbapenemase-producing Enterobacterales.
Time frame: At baseline (time of positive rectal surveillance swab)
Correlation Between Quantitative Bacterial Load (CFU/swab) in Rectal Swabs and Number of CPE-Positive High-Touch Environmental Surfaces
Spearman correlation coefficient between the quantitative bacterial load of carbapenemase-producing Enterobacterales in rectal surveillance swabs, measured by culture on CHROMagar™ KPC selective medium and expressed as colony-forming units per swab (CFU/swab), and the number of CPE-positive high-touch surfaces out of 5 sampled (bed linen, bedside table, and infusion pump), assessed by quantitative culture on CHROMagar™ KPC contact plates.
Time frame: Within 24 hours of rectal swab collection
Correlation Between PCR Cycle Threshold (Ct) Value in Rectal Swabs and Number of CPE-Positive High-Touch Environmental Surfaces
Spearman correlation coefficient between the cycle threshold (Ct) value obtained by real-time PCR (BD MAX™ system) targeting carbapenemase genes from rectal surveillance swabs positive for carbapenemase-producing Enterobacterales, and the number of CPE-positive high-touch surfaces out of 5 sampled (bed linen, bedside table, and infusion pump), assessed by quantitative culture on CHROMagar™ KPC contact plates.
Time frame: Within 24 hours of rectal swab collection
Correlation Between Quantitative Bacterial Load (CFU/swab) in Rectal Swabs and Total Colony-Forming Units Recovered from Environmental Surfaces
Spearman correlation coefficient between the quantitative bacterial load of carbapenemase-producing Enterobacterales in rectal surveillance swabs, measured by culture on CHROMagar™ KPC selective medium and expressed as colony-forming units per swab (CFU/swab), and the total colony-forming units (CFU) recovered across five high-touch surfaces (bed linen, bedside table, and infusion pump) surrounding colonized patients, assessed by quantitative culture on CHROMagar™ KPC contact plates.
Time frame: Within 24 hours of rectal swab collection
Correlation Between PCR Cycle Threshold (Ct) Value in Rectal Swabs and Total Colony-Forming Units Recovered from Environmental Surfaces
Spearman correlation coefficient between the cycle threshold (Ct) value obtained by real-time PCR (BD MAX™ system) targeting carbapenemase genes from rectal surveillance swabs positive for carbapenemase-producing Enterobacterales, and the total colony-forming units (CFU) recovered across five high-touch surfaces (bed linen, bedside table, and infusion pump) surrounding colonized patients, assessed by quantitative culture on CHROMagar™ KPC contact plates.
Time frame: Within 24 hours of rectal swab collection
Number of Index Patients with Transmission of at Least One Genetically Related CPE Strain to a Co-Hospitalized Patient
Number of index patients associated with at least one secondary case carrying a genetically related carbapenemase-producing Enterobacterales strain, confirmed by whole genome sequencing (WGS) and/or pulsed-field gel electrophoresis (PFGE), among patients hospitalized in the same intensive care unit during the study period.
Time frame: Up to 6 months
Number of Patients Meeting Predefined Criteria for Super-Spreader Classification
Number of CPE-colonized patients classified as potential super-spreaders, defined post-hoc as having a cycle threshold (Ct) value below the 25th percentile of the study population and at least 2 positive environmental surfaces with more than 50 colony-forming units (CFU) each, assessed by quantitative culture on CHROMagar™ KPC contact plates.
Time frame: At baseline (time of CPE detection and environmental sampling)
Plan to share: Yes — Individual participant data underlying the results reported in publications will be available after de-identification. Data may be shared with qualified researchers upon reasonable request to the principal investigator and after approval by the Hospital Italiano de Buenos Aires Ethics Committee, in accordance with institutional policies and applicable regulations regarding data protection and patient confidentiality. What IPD Will Be Shared? De-identified demographic data Clinical characteristics Rectal swab quantitative culture results PCR cycle threshold (Ct) values Environmental sampling results Molecular characterization and genomic data used in analyses Derived study variables
Supporting information: Study protocol, Statistical analysis plan, Clinical study report, Analytic code
Time frame: Beginning 6 months after publication and ending 5 years after publication.
Access criteria: Researchers who provide a methodologically sound proposal may access de-identified participant data for scientific purposes. Requests will be reviewed by the principal investigator and the institutional ethics committee. Data sharing agreements may be required before data release.
Start is estimated for Aug 2026; primary completion for Dec 2026, 4 months later.
Of 56 non-industry observational studies under Cross Infection, half reached primary completion within 28 months of starting (the median), counting those still running; a quarter within 17 and three quarters within 65. This study's planned 4 months is below that.
Counting every sponsor, half of 56 studies reached it within 28 months; a quarter within 17 and three quarters within 65.
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This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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