Cutaneous Microbiota Evolution in ICU Patients With CVC (ICMc)

Central venous catheters (CVCs) are necessary in up to 60% of ICU patients, representing a risk of catheter-related infections with high morbidity and mortality. Catheter colonization originating mostly from the skin is constant, but infection is not. Dysbiosis is known to be associated with pathological states and infection, for example post-antibiotic C. difficile diarrheas, or atopic dermatitis, in which flares are associated with dysbiosis and S. aureus predominance. Cutanous dysbiosis could be the missing link between catheter colonization and infection. Our hypothesis is that under the influence of multiple ICU factors (stress, antibiotic administration, local dysinfection procedures), cutaneous dybiosis appears in ICU patients with a central venous catheter. All adult ICU patients with an indication for CVC placement will be included over a 6 months period. Skin swabbing will be performed on CVC insertion site before CVC placement (baseline), and then every 3 days (or when dressing is changed) while CVC is in place, then at ICU discharge. Bacterial metagenomics using bacterial DNA extraction, 16S PCR amplification and Nanopore sequencing will allow for description of cutaneous microbiota and diversity evaluation through Shannon index. Evolution of alpha-diversity will be evaluated through time-series data analysis: comparison of Shannon index at various time points with baseline Shanonn index (before CVC placement). Standard microbiologic culture of skin swabbing will be performed. General patient characteristics and informations relative to CVC infection and treatment will be collected. This study will have no impact on patient management. Category 3 Non-Interventional Human Person Research (RIPH 3)