An observational study in Cross Infection, Intensive Care Units and Microbial Disease, sponsored by Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital. Active, not recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-04.
Sponsored by Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital · Observational
This single-center, retrospective observational study aims to compare the clinical and microbiological characteristics of initial and subsequent healthcare-associated infections (HAIs) in intensive care unit (ICU) patients.
The study will retrospectively review clinical records of adult patients admitted to the Anesthesiology and Reanimation Intensive Care Unit of Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital between January 1, 2014, and December 31, 2025. Patients aged 18 years or older who stayed in the ICU for at least 48 hours and developed at least one HAI will be eligible for inclusion.
The first HAI diagnosed during the ICU stay will be defined as the index infection, and the first new HAI occurring thereafter will be classified as the subsequent infection. The Centers for Disease Control and Prevention/National Healthcare Safety Network (CDC/NHSN) 14-day repeat infection timeframe will be considered when identifying distinct infection episodes.
The study will compare clinical characteristics of patients with and without subsequent HAIs. Among patients who develop subsequent infections, changes in infection sites and causative microorganisms will be evaluated, along with the time interval between infection episodes.
All data will be obtained from existing hospital records and infection surveillance databases. No additional diagnostic procedures, treatments, or direct patient contact will be performed.
This single-center, retrospective observational study is designed to compare the clinical and microbiological characteristics of initial and subsequent healthcare-associated infections (HAIs) among adult intensive care unit (ICU) patients. The study will be conducted at the Anesthesiology and Reanimation Intensive Care Unit of Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Türkiye.
Medical records of patients admitted to the ICU between January 1, 2014, and December 31, 2025, will be retrospectively reviewed. Eligible patients will be aged 18 years or older, have an ICU stay of at least 48 hours, and have developed at least one HAI during hospitalization. Patients with insufficient clinical, microbiological, or infection surveillance records will be excluded. All eligible patient records meeting the study criteria will be considered for inclusion.
The first HAI identified during the ICU stay will be defined as the index infection. The first subsequent HAI meeting the criteria for a new infection episode will be classified as the subsequent infection. To distinguish new infection episodes from the continuation of an existing infection, the 14-day repeat infection timeframe defined by the Centers for Disease Control and Prevention/National Healthcare Safety Network (CDC/NHSN) will be considered. Infections involving different sites and identified on the same date will be recorded as simultaneous multiple HAIs.
Data will be collected from hospital infection surveillance records, electronic medical records, ICU patient files, and microbiology laboratory results. Recorded variables will include demographic characteristics, admission diagnoses, comorbidities, malignancy status, ICU admission dates, infection diagnosis dates, invasive device use, relevant clinical exposures, infection sites, and causative microorganisms.
Two main comparisons will be performed. First, patients will be categorized according to whether they develop a subsequent HAI, and their demographic and clinical characteristics at the time of the index infection will be compared. Only exposures documented at or before the index infection will be considered when examining factors associated with subsequent infection development.
Second, among patients with subsequent HAIs, the index infection and the first subsequent infection will be compared using paired observations. Changes in infection sites and causative microorganisms will be evaluated, and the interval between infection episodes will be calculated in days. Infection-site and microorganism transitions will be summarized using transition tables.
Statistical analyses will include appropriate parametric and nonparametric tests for between-group comparisons and paired categorical analyses for within-patient comparisons. Multivariable logistic regression will be performed to investigate clinical factors independently associated with subsequent HAI development if the number of observed events is sufficient.
The study will use previously collected clinical and microbiological data exclusively. No additional diagnostic procedures, treatments, interventions, or direct patient contact will be required.
285 studies on the registry are indexed under Cross Infection; 48 are open to participants now.
This study's enrollment of 243 is below the median of 351 across 115 observational studies indexed under Cross Infection.
Browse Cross Infection studies →Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital is the lead sponsor of 75 studies on the registry; 18 are open to participants now.
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The study population will include adults aged 18 years or older admitted to the Anesthesiology and Reanimation Intensive Care Unit at Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital between January 1, 2014, and December 31, 2025. Eligible patients must have stayed in the ICU for at least 48 hours and developed at least one healthcare-associated infection (HAI). Patients will be identified retrospectively from hospital records and divided into two cohorts according to the occurrence of a subsequent HAI during the same ICU stay.
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Exclusion Criteria:
Adult patients who developed at least one healthcare-associated infection (HAI) during their intensive care unit (ICU) stay and subsequently experienced a new HAI during the same hospitalization. The first HAI will be defined as the index infection, and the first subsequent new HAI will be evaluated according to CDC/NHSN surveillance criteria, including the 14-day repeat infection timeframe. Clinical and microbiological characteristics of the index and subsequent infections will be compared using paired patient data. No study-specific interventions will be performed.
Adult patients who developed at least one healthcare-associated infection (HAI) during their intensive care unit (ICU) stay but did not experience a subsequent new HAI during the same hospitalization. The first HAI will be defined as the index infection. Demographic and clinical characteristics at the time of the index infection will be evaluated and compared with those of patients who developed subsequent HAIs. No study-specific interventions will be performed.
Change in Infection Site Between Index and First Subsequent Healthcare-Associated Infections
Among patients who develop a subsequent healthcare-associated infection (HAI), infection sites will be compared between the index infection and the first subsequent infection using paired patient-level data. Changes in infection sites will be assessed using the number and percentage of patients with different infection sites between episodes. Infection-site distributions and transitions will be presented using frequency tables and transition matrices.
Time frame: At diagnosis of the index healthcare-associated infection (baseline) and at diagnosis of the first subsequent healthcare-associated infection during the same ICU stay, assessed up to 120 days after baseline.
Change in Causative Microorganisms Between Index and First Subsequent Healthcare-Associated Infections
Among patients who develop a subsequent healthcare-associated infection (HAI), causative microorganisms identified during the index infection and the first subsequent infection will be compared using paired patient-level data. Changes in causative microorganisms will be evaluated based on microbiological records. The number and percentage of patients with changes in causative microorganisms will be reported, and microorganism transitions will be summarized using frequency distributions and transition tables.
Time frame: At diagnosis of the index healthcare-associated infection (baseline) and at diagnosis of the first subsequent healthcare-associated infection during the same ICU stay, assessed up to 120 days after baseline.
Plan to share: No — Individual participant data will not be shared due to patient confidentiality and the sensitive nature of retrospective clinical and microbiological records. Study findings will be reported in aggregate form without identifying individual patients.
Ran from Oct 2026 to primary completion in Oct 2026, 0 months.
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Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital