Correlation Between Carbapenemase-Producing Enterobacterales Load, Environmental Contamination, and Transmission in Critical Care Units
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- This is an observational study: the protocol does not assign a study treatment.
- Who it may be relevant to
- Registry conditions: Healthcare-Associated Infections (HAIs), Carbapenem-Resistant Enterobacteriaceae Colonization, Antimicrobial Resistance (AMR). Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Argentina
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
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.
Detailed description
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.
Primary outcome measures
- Correlation Between PCR Cycle Threshold (Ct) Value and Quantitative Bacterial Load (CFU/swab) in Rectal Surveillance Swabs [Time frame: At baseline (time of positive rectal surveillance swab)]
Secondary outcome measures (6)
- Correlation Between Quantitative Bacterial Load (CFU/swab) in Rectal Swabs and Number of CPE-Positive High-Touch Environmental Surfaces [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 [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 [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 [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 [Time frame: Up to 6 months]
- Number of Patients Meeting Predefined Criteria for Super-Spreader Classification [Time frame: At baseline (time of CPE detection and environmental sampling)]
Eligibility criteria
Inclusion criteria
- Age 18 years or older.
- Hospitalized in the Adult Intensive Care Unit of Hospital Italiano de Buenos Aires during the study period.
- Positive surveillance rectal swab for carbapenemase-producing Enterobacterales.
Exclusion criteria
-Patients colonized or infected with carbapenemase-producing Enterobacterales who remained in the same room for less than 48 hours.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Observational model
- Cohort
Study locations
Argentina · 1 center
- Hospital Italiano de Buenos Aires — Buenos Aires
Publications
- Tenover FC, Arbeit RD, Goering RV, Mickelsen PA, Murray BE, Persing DH, Swaminathan B. Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J Clin Microbiol. 1995 Sep;33(9):2233-9. doi: 10.1128/jcm.33.9.2233-2239.1995. No abstract available. PMID 7494007
- Gomez SA, Pasteran FG, Faccone D, Tijet N, Rapoport M, Lucero C, Lastovetska O, Albornoz E, Galas M; KPC Group; Melano RG, Corso A, Petroni A. Clonal dissemination of Klebsiella pneumoniae ST258 harbouring KPC-2 in Argentina. Clin Microbiol Infect. 2011 Oct;17(10):1520-4. doi: 10.1111/j.1469-0691.2011.03600.x. Epub 2011 Aug 18. PMID 21851480
- Wei M, Chen X, Liu J, Li T, Wang P, Wang S, Wang J, Gu L. Development and Validation of a Novel Multiplex Real-Time PCR Assay for Rapid Detection of Carbapenemase Genes in Carbapenem-Resistant Enterobacterales Isolates and Clinical Samples. Infect Drug Resist. 2024 Aug 9;17:3451-3462. doi: 10.2147/IDR.S475630. eCollection 2024. PMID 39139626
- Lerner A, Romano J, Chmelnitsky I, Navon-Venezia S, Edgar R, Carmeli Y. Rectal swabs are suitable for quantifying the carriage load of KPC-producing carbapenem-resistant Enterobacteriaceae. Antimicrob Agents Chemother. 2013 Mar;57(3):1474-9. doi: 10.1128/AAC.01275-12. Epub 2013 Jan 7. PMID 23295937
- Lerner A, Adler A, Abu-Hanna J, Cohen Percia S, Kazma Matalon M, Carmeli Y. Spread of KPC-producing carbapenem-resistant Enterobacteriaceae: the importance of super-spreaders and rectal KPC concentration. Clin Microbiol Infect. 2015 May;21(5):470.e1-7. doi: 10.1016/j.cmi.2014.12.015. Epub 2014 Dec 26. PMID 25684452
Identifiers
NCT: NCT07685132 · 7703