Impact of a training strategy on improving compliance of hand hygiene and gloving during the placement of a short peripheral venous catheter: the multicentre study CleanHand4.

BACKGROUND: Patients who have short peripheral venous catheters (PVC) face an elevated risk of developing bloodstream infections. Preventing catheter-related infections relies on implementing multiple measures, including practicing proper hand hygiene (HH) during catheter placement. METHODS: We conducted a four-part study: (1) an evaluation of HH practices through direct observation of PVC placements, coupled with the study of the microbial flora of the HCWs fingers just before the placement; (2) the development of an educational tool based on the collected observational and microbiological data; (3) the training to the HCWs observed during the first part, using this tool; and (4) the subsequent observation of the trained HCWs to measure the impact of the training on practice improvement. RESULTS: Compliant HH was observed in 23.5% of the 647 HCWs observed during PVC placement before training. The microbiological study revealed fewer pathogens on the fingertips of the HCWs practicing compliant HH compared other HCWs (2.6 vs 11,7%; p = 0.003). The comparison of practices before and after training, assessed among 180 HCWs, showed an increase in the proportion of HCWs performing compliant HH (25.0 vs 63.2%; p < 0.001). CONCLUSIONS: Training HCWs using our educational tool, which combines reminders of best practices and risk factors associated with PVC-related infections, engaging HCWs (presentation of practice evaluation), identifying professionals deviating from best practices (simulation videos), and objectively assessing fingertip contamination (microbiological study), significantly improved compliance with HH gestures and glove usage. We encourage infection control teams to utilize this tool to raise awareness among HCWs responsible for PVC placement about the risk of infection associated inadequate hand hygiene.

White matter volume and white/gray matter ratio in mammalian species as a consequence of the universal scaling of cortical folding.

Because the white matter of the cerebral cortex contains axons that connect distant neurons in the cortical gray matter, the relationship between the volumes of the 2 cortical compartments is key for information transmission in the brain. It has been suggested that the volume of the white matter scales universally as a function of the volume of the gray matter across mammalian species, as would be expected if a global principle of wiring minimization applied. Using a systematic analysis across several mammalian clades, here we show that the volume of the white matter does not scale universally with the volume of the gray matter across mammals and is not optimized for wiring minimization. Instead, the ratio between volumes of gray and white matter is universally predicted by the same equation that predicts the degree of folding of the cerebral cortex, given the clade-specific scaling of cortical thickness, such that the volume of the gray matter (or the ratio of gray to total cortical volumes) divided by the square root of cortical thickness is a universal function of total cortical volume, regardless of the number of cortical neurons. Thus, the very mechanism that we propose to generate cortical folding also results in compactness of the white matter to a predictable degree across a wide variety of mammalian species.

PLGA-PVA-PEG Single Emulsion Method as a Candidate for Aminolevulinic Acid (5-ALA) Encapsulation: Laboratory Scaling Up and Stability Evaluation.

One of the most widely used molecules used for photodynamic therapy (PDT) is 5-aminolevulinic acid (5-ALA), a precursor in the synthesis of tetrapyrroles such as chlorophyll and heme. The 5-ALA skin permeation is considerably reduced due to its hydrophilic characteristics, decreasing its local bioavailability and therapeutic effect. For this reason, five different systems containing polymeric particles of poly [D, L-lactic-co-glycolic acid (PLGA)] were developed to encapsulate 5-ALA based on single and double emulsions methodology. All systems were standardized (according to the volume of reagents and mass of pharmaceutical ingredients) and compared in terms of laboratory scaling up, particle formation and stability over time. UV-VIS spectroscopy revealed that particle absorption/adsorption of 5-ALA was dependent on the method of synthesis. Different size distribution was observed by DLS and NTA techniques, revealing that 5-ALA increased the particle size. The contact angle evaluation showed that the system hydrophobicity was dependent on the surfactant and the 5-ALA contribution. The FTIR results indicated that the type of emulsion influenced the particle formation, as well as allowing PEG functionalization and interaction with 5-ALA. According to the 1H-NMR results, the 5-ALA reduced the T1 values of polyvinyl alcohol (PVA) and PLGA in the double emulsion systems due to the decrease in molecular packing in the hydrophobic region. The results indicated that the system formed by single emulsion containing the combination PVA-PEG presented greater stability with less influence from 5-ALA. This system is a promising candidate to successfully encapsulate 5-ALA and achieve good performance and specificity for in vitro skin cancer treatment.

Similar Microglial Cell Densities across Brain Structures and Mammalian Species: Implications for Brain Tissue Function.

Microglial cells play essential volume-related actions in the brain that contribute to the maturation and plasticity of neural circuits that ultimately shape behavior. Microglia can thus be expected to have similar cell sizes and even distribution both across brain structures and across species with different brain sizes. To test this hypothesis, we determined microglial cell densities (the inverse of cell size) using immunocytochemistry to Iba1 in samples of free cell nuclei prepared with the isotropic fractionator from brain structures of 33 mammalian species belonging to males and females of five different clades. We found that microglial cells constitute ∼7% of non-neuronal cells in different brain structures as well as in the whole brain of all mammalian species examined. Further, they vary little in cell density compared with neuronal cell densities within the cerebral cortex, across brain structures, across species within the same clade, and across mammalian clades. As a consequence, we find that one microglial cell services as few as one and as many as 100 neurons in different brain regions and species, depending on the local neuronal density. We thus conclude that the addition of microglial cells to mammalian brains is governed by mechanisms that constrain the size of these cells and have remained conserved over 200 million years of mammalian evolution. We discuss the probable consequences of such constrained size for brain function in health and disease.SIGNIFICANCE STATEMENT Microglial cells are resident macrophages of the CNS, with key functions in recycling synapses and maintaining the local environment in health and disease. We find that microglial cells occur in similar densities in the brains of different species and in the different structures of each individual brain, which indicates that these cells maintain a similar average size in mammalian evolution, suggesting in turn that the volume monitored by each microglial cell remains constant across mammals. Because the density of neurons is highly variable across the same brain structures and species, our finding implies that microglia-dependent functional recovery may be particularly difficult in those brain structures and species with high neuronal densities and therefore fewer microglial cells per neuron.

Mefloquine synergism with anti-tuberculosis drugs and correlation to membrane effects: Biologic, spectroscopic and molecular dynamics simulations studies.

Studies displaying the combination of mefloquine (MFL) with anti-tuberculosis (TB) substances are limited in the literature. In this work, the effect of MFL-association with two first-line anti-TB drugs and six fluoroquinolones was evaluated against Mycobacterium tuberculosis drug resistant strains. MFL showed synergistic interaction with isoniazid, pyrazinamide, and several fluoroquinolones, reaching fractional inhibitory concentration indexes (FICIs) ranging from 0.03 to 0.5. In order to better understand the observed results, two approaches have been explored: (i) spectroscopic responses attributed to the effect of MFL on physicochemical properties related to a liposomal membrane model composed by soybean asolectin; (ii) molecular dynamics (MD) simulation data regarding MFL interaction with a membrane model based on PIM2, a lipid constituent of the mycobacterial cell wall. FTIR and NMR data showed that MFL affects expressively the region between the phosphate and the first methylene groups of soybean asolectin membranes, disordering these regions. MD simulations results detected high MFL density in the glycolipid interface and showed that the drug increases the membrane lateral diffusion, enhancing its permeability. The obtained results suggest that synergistic activities related to MFL are attributed to its effect of lipid disorder and membrane permeability enhancement.

Staphylococcus capitis isolated from bloodstream infections: a nationwide 3-month survey in 38 neonatal intensive care units.

To increase the knowledge about S. capitis in the neonatal setting, we conducted a nationwide 3-month survey in 38 neonatal intensive care units (NICUs) covering 56.6% of French NICU beds. We demonstrated 14.2% of S. capitis BSI (S.capBSI) among nosocomial BSIs. S.capBSI incidence rate was 0.59 per 1000 patient-days. A total of 55.0% of the S.capBSIs were late onset catheter-related BSIs. The S. capitis strains infected preterm babies (median gestational age 26 weeks, median birth weight 855 g). They were resistant to methicillin and aminoglycosides and belonged to the NRCS-A clone. Evolution was favorable in all but one case, following vancomycin treatment.

Emergence of blaNDM-7-Producing Enterobacteriaceae in Gabon, 2016.

Reports of carbapenemase-producing Enterobacteriaceae in Africa remain rare and assess mostly blaOXA-48-producing isolates from Mediterranean countries and South Africa. We identified blaNDM-7-producing Enterobacteriaceae in Gabon in 2016. The isolates contained blaNDM-7 IncX3 plasmids that were unusual and similar to the one described in a colistin-resistant Klebsiella pneumoniae SZ04 isolate from China.

Cellular Scaling Rules for the Brains of Marsupials: Not as "Primitive" as Expected.

In the effort to understand the evolution of mammalian brains, we have found that common relationships between brain structure mass and numbers of nonneuronal (glial and vascular) cells apply across eutherian mammals, but brain structure mass scales differently with numbers of neurons across structures and across primate and nonprimate clades. This suggests that the ancestral scaling rules for mammalian brains are those shared by extant nonprimate eutherians - but do these scaling relationships apply to marsupials, a sister group to eutherians that diverged early in mammalian evolution? Here we examine the cellular composition of the brains of 10 species of marsupials. We show that brain structure mass scales with numbers of nonneuronal cells, and numbers of cerebellar neurons scale with numbers of cerebral cortical neurons, comparable to what we have found in eutherians. These shared scaling relationships are therefore indicative of mechanisms that have been conserved since the first therians. In contrast, while marsupials share with nonprimate eutherians the scaling of cerebral cortex mass with number of neurons, their cerebella have more neurons than nonprimate eutherian cerebella of a similar mass, and their rest of brain has fewer neurons than eutherian structures of a similar mass. Moreover, Australasian marsupials exhibit ratios of neurons in the cerebral cortex and cerebellum over the rest of the brain, comparable to artiodactyls and primates. Our results suggest that Australasian marsupials have diverged from the ancestral Theria neuronal scaling rules, and support the suggestion that the scaling of average neuronal cell size with increasing numbers of neurons varies in evolution independently of the allocation of neurons across structures.

Association between sedentary behavior time and waist-to-height ratio in preschool children.

OBJECTIVES: To explore the association between sedentary behavior time (SB), and waist-to-height ratio (WHtR) in preschool children. METHODS: This study included 646 preschool children (4- to 6-years old). WHtR was calculated as the ratio of waist/height with a cutoff of 0.5 used to define risk of abdominal obesity. Sedentary behavior was measured during 7 consecutive days by accelerometer. Logistic regression was used to determine the association between SB and WHtR. RESULTS: The prevalence of central obesity (WHtR) was 52.4 and 39.2% for girls and boys, respectively. Boys classified as being at risk for central obesity were more likely to spend more time in SB (OR: 1.6; CI: 1.1-2.5; P ≤ 0.05), adjusted by age (P ≤ 0.001). CONCLUSIONS: Our data suggested that boys classified as having higher SB were more likely to having more central obesity. Am. J. Hum. Biol. 28:746-748, 2016. © 2016 Wiley Periodicals, Inc.

The association between intimate partner domestic violence and the food security status of poor families in Brazil.

OBJECTIVE: To assess the association between physical intimate partner violence and household food security within households with schoolchildren. DESIGN: Cross-sectional study. SETTING: Salvador, Bahia, north-eastern Brazil. SUBJECTS: The study was conducted in 1019 households with students. Violence between couples was evaluated using the Portuguese version of the revised Conflict Tactics Scales (CTS2), previously adapted and validated for use in Brazil. The Brazilian Food Insecurity Scale (BFIS) was used to identify food insecurity. We also obtained socio-economic information for each participant. We used multivariate Poisson regression to assess the associations of interest. RESULTS: According to the results of the BFIS, 62·5% of the households were found to experience food insecurity, including 19·5% moderate food insecurity and 6·5% severe food insecurity. The prevalence of minor physical violence was 9·6% (95% CI 7·8, 11·4%) and of severe physical violence was 4·7% (95% CI 3·4, 6·0%) among the couples. In the final multivariate model, it was found that couples reporting minor (prevalence ratio=1·23; 95% CI 1·12, 1·35) and severe (prevalence ratio=1·16; 95% CI 1·00, 1·34) physical violence were more likely to be experiencing household food insecurity, compared with those not reporting physical violence. CONCLUSIONS: Physical intimate partner violence was associated with food insecurity of households. The present study brings new data to the subject of the role of violence in the context of food insecurity.

The YEASTRACT database: an upgraded information system for the analysis of gene and genomic transcription regulation in Saccharomyces cerevisiae.

The YEASTRACT (http://www.yeastract.com) information system is a tool for the analysis and prediction of transcription regulatory associations in Saccharomyces cerevisiae. Last updated in June 2013, this database contains over 200,000 regulatory associations between transcription factors (TFs) and target genes, including 326 DNA binding sites for 113 TFs. All regulatory associations stored in YEASTRACT were revisited and new information was added on the experimental conditions in which those associations take place and on whether the TF is acting on its target genes as activator or repressor. Based on this information, new queries were developed allowing the selection of specific environmental conditions, experimental evidence or positive/negative regulatory effect. This release further offers tools to rank the TFs controlling a gene or genome-wide response by their relative importance, based on (i) the percentage of target genes in the data set; (ii) the enrichment of the TF regulon in the data set when compared with the genome; or (iii) the score computed using the TFRank system, which selects and prioritizes the relevant TFs by walking through the yeast regulatory network. We expect that with the new data and services made available, the system will continue to be instrumental for yeast biologists and systems biology researchers.

Food and nutrition insecurity: a marker of vulnerability to asthma symptoms.

OBJECTIVE: To evaluate the association between food and nutrition insecurity and asthma in children from Latin America. DESIGN: Cross-sectional study. SETTING: São Francisco do Conde, Bahia, north-eastern Brazil. SUBJECTS: The study included 1307 children aged 6-12 years from public elementary schools. Asthma symptoms were collected using a questionnaire that was translated and adapted from the International Study of Asthma and Allergies in Childhood, phase III. The diagnosis of asthma was determined based on reports of wheezing in the previous 12 months. The Brazilian Food Insecurity Scale was used to identify food insecurity. We also obtained demographic, socio-economic and anthropometric information for each participant. We used multivariate logistic regression analyses to assess the associations of interest. RESULTS: Of the children surveyed, 10·4% had a history of wheezing and 64·5% had some degree of food and nutrition insecurity. We found a positive dose-response relationship and statistically significant associations of asthma with moderate (OR = 1·71, 95% CI 1·01, 2·89) and severe (OR = 2·51, 95% CI 1·28, 4·93) food and nutrition insecurity. CONCLUSIONS: The results show that moderate and severe food and nutrition insecurity are markers of vulnerability to wheezing. It is important to note that the results of studies in this field have potential implications for social policies that promote food security. Further studies to identify the mechanisms involved in the relationship between food and nutrition insecurity and asthma are needed.

Carbapenem-producing Enterobacteriaceae in mothers and newborns in southeast Gabon, 2022.

Introduction: Infections caused by carbapenemase-producing Enterobacteriaceae (CPE) pose a significant threat, leading to severe morbidity and mortality among newborns. Methods: This study, conducted at Franceville hospital's maternity and neonatology wards from February 22nd to June 20th, 2022, investigated the prevalence of CPE in 197 parturients and 203 newborns. Rectal swabs were taken from parturients before delivery and from newborns 30 minutes after birth. Blood culture samples were collected if signs of infection were observed in newborns during a 28-day follow-up. A total of 152 environmental samples were obtained, comprising 18 from sinks, 14 from incubators, 27 from cradles, 39 from maternal beds, 14 from tables and desks, four from the two baby scales and 36 from bedside furniture. Results: None of the 203 newborns were found to be CPE carriers 30 minutes after delivery. CPE carriage was found in 4.6% of mothers. When comparing colonized and uncolonized parturients, well-established risk factors for CPE carriage, such as recent hospitalization and antibiotic therapy, were more frequently observed among CPE carriers (33.3 vs 10.6% for hospitalization in the past 15 days; 55.5 vs 30.3% for hospitalization during pregnancy, and 55.5 vs 35.1% for antibiotic therapy during pregnancy). Notably, the prevalence of treatment with amoxicillin and clavulanic acid was 44.4% in CPE carriers compared to 17.0% in non-carriers. The incidence density of CPE-associated bloodstream infection was 0.49 per 100 newborns, accounting for a fatal case of CPE-associated bacteremia identified in one of the 203 newborns. Seven environmental samples returned positive for CPE (5 sinks and two pieces of furniture). Whole genome sequencing, performed on the 25 CPE isolates, revealed isolates carrying blaNDM-7 (n=10), blaNDM-5 (n=3), blaOXA181 (n=10), blaOXA48 (n=2) or blaOXA244 (n=1), along with genetic traits associated with the ability to cause severe and difficult-to-treat infections in newborns. Core genome comparison revealed nine CPE belonging to three international high-risk clones: E. coli ST410 (four mothers and a sink), two E. coli ST167 (a mother and a piece of furniture), and K. pneumoniae ST307 (a sink and a piece of furniture), with highly similar genetic backgrounds shared by maternal and environmental isolates, suggesting maternal contamination originating from the environment. Discussion: Our study reveals key findings may guide the implementation of infection control measures to prevent nosocomial infections in newborns: the prevalence of CPE carriage in one out of 20 parturients, an infection occurring in one out of 400 newborns, substantial contamination of the care environment, clinical and environmental CPE isolates possessing genetic traits associated with the ability to cause severe and challenging infections, and clonal relationships between clinical and environmental isolates suggesting CPE spread within the wards, likely contributing to the acquisition and colonization of CPE by parturients during pregnancy.

Carbapenem- and colistin-resistant Enterobacterales in intensive care unit patients in Mediterranean countries, 2019.

Introduction: The colonization of patients by carbapenemase-producing Enterobacterales (CPE) has been associated with heightened mortality, especially in vulnerable individuals within intensive care units (ICUs). Our study aimed to comprehensively assess CPE prevalence among ICU patients across the Mediterranean region pre-COVID-19, conducting a multicenter prevalence study in the first quarter of 2019. Methods: We collected clinical data and rectal or fecal samples from 256 ICU patients for CPE testing. Additionally, we performed whole-genome sequencing on 40 representative CPE strains to document their molecular characteristics. Results: Among the 256 patients, CPE was detected in 73 samples (28.5%), with prevalence varying from 3.3 to 69.0% across participating centers. We observed 13 colistin-resistant CPE strains, affecting three ICUs. Genetic analysis revealed highly diverse E. coli and K. pneumoniae strains, predominantly from international high-risk clones. Notably, blaOXA-48 and blaNDM-1 were the most prevalent carbapenemase genes. Molecular typing uncovered potential patient clusters in six centers. Significantly, longer hospital stays were associated with increased CPE carriage (p < 0.001). Nine centers across Morocco, Tunisia, Egypt, and Lebanon voluntarily participated. Discussion: Our study provides CPE prevalence in Mediterranean ICUs and reaffirms established CPE presence in this setting but also provides updates on the molecular diversity of CPE strains. These findings highlight the imperative of reinforcing infection control measures in the participating ICUs to curtail escalated mortality rates, and of strictly applying isolation measures around patients originating from the Mediterranean region when transferred to other healthcare institutions.

CC9 livestock-associated Staphylococcus aureus emerges in bloodstream infections in French patients unconnected with animal farming.

We report 4 bloodstream infections associated with CC9 agr type II Staphylococcus aureus in individuals without animal exposure. We demonstrate, by microarray analysis, the presence of egc cluster, fnbA, cap operon, lukS, set2, set12, splE, splD, sak, epiD, and can, genomic features associated with a high virulence potential in humans.

YEASTRACT: providing a programmatic access to curated transcriptional regulatory associations in Saccharomyces cerevisiae through a web services interface.

The YEAst Search for Transcriptional Regulators And Consensus Tracking (YEASTRACT) information system (http://www.yeastract.com) was developed to support the analysis of transcription regulatory associations in Saccharomyces cerevisiae. Last updated in June 2010, this database contains over 48,200 regulatory associations between transcription factors (TFs) and target genes, including 298 specific DNA-binding sites for 110 characterized TFs. All regulatory associations stored in the database were revisited and detailed information on the experimental evidences that sustain those associations was added and classified as direct or indirect evidences. The inclusion of this new data, gathered in response to the requests of YEASTRACT users, allows the user to restrict its queries to subsets of the data based on the existence or not of experimental evidences for the direct action of the TFs in the promoter region of their target genes. Another new feature of this release is the availability of all data through a machine readable web-service interface. Users are no longer restricted to the set of available queries made available through the existing web interface, and can use the web service interface to query, retrieve and exploit the YEASTRACT data using their own implementation of additional functionalities. The YEASTRACT information system is further complemented with several computational tools that facilitate the use of the curated data when answering a number of important biological questions. Since its first release in 2006, YEASTRACT has been extensively used by hundreds of researchers from all over the world. We expect that by making the new data and services available, the system will continue to be instrumental for yeast biologists and systems biology researchers.

Factors associated with food insecurity in households of public school students of Salvador City, Bahia, Brazil.

This cross-sectional study was conducted to find out the factors associated with food insecurity (FI) in households of the students aged 6-12 years in public schools of Salvador city, Bahia, Brazil. The study included 1,101 households. Food and nutritional insecurity was measured using the Brazilian Food Insecurity Scale (BFIS). Data on socioeconomic and demographic characteristics as well as environmental and housing conditions were collected during the interviews conducted with the reference persons. Multivariate polytomous logistic regression was used in assessing factors associated with food insecurity. We detected prevalence of food insecurity in 71.3% of the households. Severe and moderate forms of FI were diagnosed in 37.1% of the households and were associated with: (i) female gender of the reference person in the households (OR 2.21, 95% CI 1.47-3.31); (ii) a monthly per-capita income below one-fourth of the minimum wage (US$ 191.73) (OR 2.63, 95% CI 1.68-4.08); (iii) number of residents per bedroom below 3 persons (OR 1.91, 95% CI 1.23-2.96); and (iv) inadequate housing conditions (OR 1.84, 95% CI 1.12-4.49). Socioeconomic inequalities determine the factors associated with FI of households in Salvador, Bahia. Identifying vulnerabilities is necessary to support public policies in reducing food insecurity in the country. The results of the present study may be used in re-evaluating strategies that may limit the inequalities in school environment.

Association between Socioeconomic Factors, Food Insecurity, and Dietary Patterns of Adolescents: A Latent Class Analysis.

Socioeconomic factors and food insecurity play a fundamental role in the food choices of adolescents, and in addition to influencing access to food, they also have significant effects on dietary patterns. The objectives of this study were to identify the dietary patterns of adolescents through the application of latent class analysis and to evaluate their association with socioeconomic variables and food insecurity. This cross-sectional study was conducted with adolescents aged between 11 and 17 years from public schools. Latent class analysis was used to identify the dietary patterns. Associations between socioeconomic factors, food insecurity and dietary patterns were assessed using multinomial logistic regression (odds ratio (OR); 95% confidence interval (CI)). Among the 1215 participants in the study, four dietary patterns were identified: "Mixed", "Low consumption", "Prudent" and "Diverse". A "Diverse" dietary pattern was associated with a lower economic stratum (OR:2.02; CI:1.26-3.24). There was no association between food insecurity and identified dietary patterns. These results highlight the importance of promoting healthy eating in this age group at all socioeconomic levels, especially the lowest level.

Influence of body fat and level of physical activity on rate-pressure product at rest in preschool children.

OBJECTIVE: The rate-pressure product (RPP) has strong correlation with the maximal oxygen consumption and is an indicator of myocardium stress being considered as the best indirect method to measure myocardial oxygen consumption. However, to the best of our knowledge, no studies have addressed in preschool children. The aim of this study was to analyze the influence of percentage of body fat (%BF) and physical activity (PA) patterns on RPP at Rest (RPPrest) as a marker of cardiac load in Preschool children. METHODS: The study comprised 593 preschool children aged 3-6 years-old. Heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressure were taken at rest. The RPP was then calculated. The %BF was estimated from four skinfolds thicknesses and PA was assessed during 7 consecutive days by accelerometry. RESULTS: Our data showed that only %BF (P ≤ 0.001) and vigorous PA (P ≤ 0.05) contributed significantly toward RPPrest variation. However, the multivariate analysis showed that only %BF (P ≤ 0.05) had a significant influence on RPPrest variation. CONCLUSION: These findings suggest that on preschoolers there is an association between RPP at rest and %BF.

Strong Biofilm Formation and Low Cloxacillin Susceptibility in Biofilm-Growing CC398 Staphylococcus aureus Responsible for Bacteremia in French Intensive Care Units, 2021.

A prospective 3-month study carried out in 267 ICUs revealed an S. aureus nosocomial bacteremia in one admitted patient out of 110 in adult and pediatric sectors, and in one out of 230 newborns; 242 S. aureus bacteremias occurred during the study, including 7.9% MRSA-bacteremias. In one ICU out of ten, the molecular characteristics, antimicrobial susceptibility profiles and biofilm production of the strains responsible for S. aureus bacteremia were studied. Of the 53 strains studied, 9.4% were MRSA and 52.8% were resistant to erythromycin. MLST showed the predominance of CC398 (37.7% of the strains) followed by CC8 (17.0%), CC45 (13.2%) and CC30 (9.4%). The lukF/S genes were absent from our isolates and tst-1 was found in 9.4% of the strains. Under static conditions and without exposure to glucose, biofilm production was rare (9.4% of the strains, without any CC398). The percentage increased to 62.3% for strains grown in broth supplemented with 1% glucose (including 7 out of 9 CC8 and 17 out of the 20 CC398). Further study of the CC398, including whole genome sequencing, revealed (1) highly frequent patient death within seven days after CC398 bacteremia diagnosis (47.4%), (2) 95.0% of the strains producing biofilm when exposed to sub-inhibitory concentrations of cloxacillin, (3) a stronger biofilm production following exposure to cloxacillin than that observed in broth supplemented with glucose only (p < 0.001), (4) a high minimum biofilm eradication concentration of cloxacillin (128 mg/L) indicating a low cloxacillin susceptibility of biofilm-growing CC398, (5) 95.0% of the strains carrying a ϕSa-3 like prophage and its particular evasion cluster (i.e., yielding chp and scin genes), and (6) 30.0% of the strains carrying a ϕMR11-like prophage and yielding a higher ability to produce biofilm. Our results provide evidence that active surveillance is required to avoid spreading of this virulent staphylococcal clone.