Surveillance and attribution of ambulatory central line-associated bloodstream infections in a pediatric healthcare system.

BACKGROUND: Central line-associated bloodstream infections (CLABSI) in ambulatory pediatric populations are difficult to track at an institutional level, especially for complex patients seen by multiple divisions and home health infusion agencies. METHODS: A multidisciplinary team comprised of key stakeholders from divisions with the most patients discharged with a central line utilized Lean Six Sigma methodology of Define-Measure-Analyze-Design-Verify (DMADV) to create a standardized data collection process for all ambulatory CLABSIs and infection event reviews. RESULTS: A surveillance workflow was created to track, identify, and confirm ambulatory CLABSIs in all patients with an indwelling central line. Defined surveillance criteria included scope of patients eligible for ambulatory CLABSI surveillance, numerator definitions, and denominator calculations. Additionally, a novel attribution method was created for ambulatory CLABSIs in complex patient populations shared among multiple divisions and home care infusion services. CONCLUSIONS: This report is a novel institutional approach to accurately surveil, attribute, and calculate ambulatory CLABSI data in a pediatric healthcare system.

Dodging the bundle-Persistent healthcare-associated rhinovirus infection throughout the pandemic.

INTRODUCTION: Healthcare-associated viral infections (HAVI) are a common cause of patient harm in the pediatric population. We implemented a HAVI prevention bundle in 2015, which included 6 core elements: caregiver screening, symptom-based isolation, personal protective equipment (PPE), hand hygiene, staff illness procedures, and monitoring of environmental cleanliness. Enhanced bundle elements were introduced at the start of the COVID-19 pandemic, which provided an opportunity to observe the effectiveness of the bundle with optimal adherence to prevention practices, and to measure the impact on respiratory HAVI epidemiology. METHODS: Respiratory HAVIs were confirmed through review of medical records and application of the National Health Safety Network (NHSN) surveillance criteria for upper respiratory infections (URIs) with predetermined incubation periods for unit attribution. Descriptive statistics of the study population were examined, and comparative analyses were performed on demographic and process metrics. Data analysis was conducted using R statistical software. RESULTS: We observed an overall decrease in respiratory HAVI of 68%, with prepandemic rates of 0.19 infections per 1,000 patient significantly decreased to a rate of 0.06 per 1,000 patient days in the pandemic period (P < .01). Rhinovirus made up proportionally more of our respiratory HAVI in the pandemic period (64% vs 53%), with respiratory HAVI secondary only to rhinovirus identified during 8 of 16 months in the pandemic period. Compliance with our HAVI prevention bundle significantly improved during pandemic period. CONCLUSIONS: Enhancement of our HAVI bundle during the COVID-19 pandemic contributed toward significant reduction in nosocomial transmission of respiratory HAVI. Even with prevention practices optimized, respiratory HAVIs secondary to rhinovirus continued to be reported, likely due to the capacity of rhinovirus to evade bundle elements in hospital, and infection prevention efforts at large in the community, leaving vulnerable patients at continued risk.

Journal club: "Racial disparities in catheter related urinary tract infections among elderly trauma patients in the US".

In this article for Journal Club commentary entitled "Racial Disparities in Catheter Related Urinary Tract Infections Among Elderly Trauma Patients in the US", Keneally et al, conducted a study with the goal of assessing the role of social disparities in catheter associated urinary tract infections (CAUTIs). This cross-sectional study utilized secondary data to determine the possible CAUTI risk in ventilated, older (≥ 65 years of age) trauma patients exploring possible racial structural bias in healthcare. The analysis addressed the following questions in this specific population:While this study does consider race and discusses structural biases, which are important and sparsely researched in healthcare-associated infection (HAI) outcomes, the practice implementations are somewhat limited due to study design and analysis. Therefore, the focus of this Journal Club commentary will be reviewing basic steps Infection Preventionists (IPs) can take to critically appraise the literature for application in their facility's patient population.

Development of a novel prevention bundle for pediatric healthcare-associated viral infections.

OBJECTIVE: To reduce the healthcare-associated viral infection (HAVI) rate to 0.70 infections or fewer per 1,000 patient days by developing and sustaining a comprehensive prevention bundle. SETTING: A 546-bed quaternary-care children's hospital situated in a large urban area.PatientsInpatients with a confirmed HAVI were included. These HAVIs were identified through routine surveillance by infection preventionists and were confirmed using National Healthcare Safety Network definitions for upper respiratory infections (URIs), pneumonia, and gastroenteritis. METHODS: Quality improvement (QI) methods and statistical process control (SPC) analyses were used in a retrospective observational analysis of HAVI data from July 2012 through June 2016. RESULTS: In total, 436 HAVIs were identified during the QI initiative: 63% were URIs, 34% were gastrointestinal infections, and 2.5% were viral pneumonias. The most frequent pathogens were rhinovirus (n=171) and norovirus (n=83). Our SPC analysis of HAVI rate revealed a statistically significant reduction in March 2014 from a monthly average of 0.81 to 0.60 infections per 1,000 patient days. Among HAVIs with event reviews completed, 15% observed contact with a sick primary caregiver and 15% reported contact with a sick visitor. Patient outcomes identified included care escalation (37%), transfer to ICU (11%), and delayed discharge (19%). CONCLUSIONS: The iterative development, implementation, and refinement of targeted prevention practices was associated with a significant reduction in pediatric HAVI. These practices were ultimately formalized into a comprehensive prevention bundle and provide an important framework for both patient and systems-level interventions that can be applied year-round and across inpatient areas.

Identification of a novel mechanism of action of fingolimod (FTY720) on human effector T cell function through TCF-1 upregulation.

BACKGROUND: Fingolimod (FTY720), the first oral treatment for multiple sclerosis (MS), blocks immune cell trafficking and prevents disease relapses by downregulation of sphingosine-1-phosphate receptor. We determined the effect of FTY720 on human T cell activation and effector function. METHODS: T cells from MS patients and healthy controls were isolated to measure gene expression profiles in the presence or absence of FTY720 using nanostring and quantitative real-time polymerase chain reaction (qPCR). Cytokine protein expression was measured using luminex assay and flow cytometry analysis. Lentivirus vector carrying short hairpin RNA (shRNA) was used to knock down the expression of specific genes in CD4+ T cells. Chromatin immunoprecipitation was performed to assess T cell factor 1 (TCF-1) binding to promoter regions. Luciferase assays were performed to test the direct regulation of interferon gamma (IFN-γ) and granzyme B (GZMB) by TCF-1. Western blot analysis was used to assess the phosphorylation status of Akt and GSK3ß. RESULTS: We showed that FTY720 treatment not only affects T cell trafficking but also T cell activation. Patients treated with FTY720 showed a significant reduction in circulating CD4 T cells. Activation of T cells in presence of FTY720 showed a less inflammatory phenotype with reduced production of IFN-γ and GZMB. This decreased effector phenotype of FTY720-treated T cells was dependent on the upregulation of TCF-1. FTY720-induced TCF-1 downregulated the pathogenic cytokines IFN-γ and GZMB by binding to their promoter/enhancer regions and mediating epigenetic modifications. Furthermore, we observed that TCF-1 expression was lower in T cells from multiple sclerosis patients than in those from healthy individuals, and FTY720 treatment increased TCF-1 expression in multiple sclerosis patients. CONCLUSIONS: These results reveal a previously unknown mechanism of the effect of FTY720 on human CD4+ T cell modulation in multiple sclerosis and demonstrate the role of TCF-1 in human T cell activation and effector function.

Circulating microRNAs as biomarkers for disease staging in multiple sclerosis.

OBJECTIVE: MicroRNAs (miRNAs) are single-stranded, small noncoding RNAs that regulate gene expression. Because they are stable in serum, they are being developed as biomarkers for cancer and other diseases. In multiple sclerosis (MS), miRNAs have been studied in cell populations but not in the circulation. In MS, a major challenge is to develop immune biomarkers to monitor disease. We asked whether circulating miRNAs could be identified in MS and whether they are linked to disease stage and/or disability. METHODS: A total of 368 miRNAs were measured in ethylenediaminetetraacetic acid plasma in 10 relapsing-remitting MS (RRMS) patients, 9 secondary progressive MS (SPMS) patients, and 9 healthy controls (HCs) using miRCURY LNA™ Universal RT microRNA polymerase chain reaction panels. Nineteen miRNAs from this discovery set were validated using qPCR on an independent set of 50 RRMS patients, 51 SPMS patients, and 32 HCs. RESULTS: We found that circulating miRNAs are differentially expressed in RRMS and SPMS versus HCs and in RRMS versus SPMS. We also found miRNAs to be linked to Expanded Disability Status Scale (EDSS). hsa-miR-92a-1* was identified in the largest number of comparisons. It was different in RRMS versus SPMS, and RRMS versus HCs, and showed an association with EDSS and disease duration. miR-92 has target genes involved in cell cycle regulation and cell signaling. The let-7 family of miRNAs differentiated SPMS from HCs and RRMS from SPMS. let-7 miRNAs regulate stem cell differentiation and T cell activation, activate Toll-like receptor 7, and are linked to neurodegeneration. hsa-miR-454 differentiated RRMS from SPMS, and hsa-miR-145 differentiated RRMS from HCs and RRMS from SPMS. Interestingly, the same circulating miRNAs (let-7 and miR-92) that were differentially expressed in RRMS versus SPMS also differentiated amyotrophic lateral sclerosis (ALS) from RRMS subjects, but were not different between SPMS and ALS, suggesting that similar processes may occur in SPMS and ALS. INTERPRETATION: Our results establish circulating miRNAs as a readily accessible blood biomarker to monitor disease in MS.

Accurate measurement of peripheral blood mononuclear cell concentration using image cytometry to eliminate RBC-induced counting error.

Peripheral blood mononuclear cells (PBMCs) have been widely researched in the fields of immunology, infectious disease, oncology, transplantation, hematological malignancy, and vaccine development. Specifically, in immunology research, PBMCs have been utilized to monitor concentration, viability, proliferation, and cytokine production from immune cells, which are critical for both clinical trials and biomedical research. The viability and concentration of isolated PBMCs are traditionally measured by manual counting with trypan blue (TB) using a hemacytometer. One of the common issues of PBMC isolation is red blood cell (RBC) contamination. The RBC contamination can be dependent on the donor sample and/or technical skill level of the operator. RBC contamination in a PBMC sample can introduce error to the measured concentration, which can pass down to future experimental assays performed on these cells. To resolve this issue, RBC lysing protocol can be used to eliminate potential error caused by RBC contamination. In the recent years, a rapid fluorescence-based image cytometry system has been utilized for bright-field and fluorescence imaging analysis of cellular characteristics (Nexcelom Bioscience LLC, Lawrence, MA). The Cellometer image cytometry system has demonstrated the capability of automated concentration and viability detection in disposable counting chambers of unpurified mouse splenocytes and PBMCs stained with acridine orange (AO) and propidium iodide (PI) under fluorescence detection. In this work, we demonstrate the ability of Cellometer image cytometry system to accurately measure PBMC concentration, despite RBC contamination, by comparison of five different total PBMC counting methods: (1) manual counting of trypan blue-stained PBMCs in hemacytometer, (2) manual counting of PBMCs in bright-field images, (3) manual counting of acetic acid lysing of RBCs with TB-stained PBMCs, (4) automated counting of acetic acid lysing of RBCs with PI-stained PBMCs, and (5) AO/PI dual staining method. The results show comparable total PBMC counting among all five methods, which validate the AO/PI staining method for PBMC measurement in the image cytometry method.

Interleukin-33 primes mast cells for activation by IgG immune complexes.

Mast cells (MCs) are heterogeneous cells whose phenotype is modulated by signals received from the local microenvironment. Recent studies have identified the mesenchymal-derived cytokine IL-33 as a potent direct activator of MCs, as well as regulator of their effector phenotype, and have implicated this activity in the ability of mast cells to contribute to murine experimental arthritis. We explored the hypothesis that IL-33 enables participation of synovial MCs in murine K/BxN arthritis by promoting their activation by IgG immune complexes. Compared to wild-type (WT) control mice, transgenic animals lacking the IL-33 receptor ST2 exhibited impaired MC-dependent immune complex-induced vascular permeability (flare) and attenuated K/BxN arthritis. Whereas participation of MCs in this model is mediated by the activating IgG receptor FcγRIII, we pre-incubated bone marrow-derived MCs with IL-33 and found not only direct induction of cytokine release but also a marked increase in FcγRIII-driven production of critical arthritogenic mediators including IL-1ß and CXCL2. This "priming" effect was associated with mRNA accumulation rather than altered expression of Fcγ receptors, could be mimicked by co-culture of WT but not ST2(-/-) MCs with synovial fibroblasts, and was blocked by antibodies against IL-33. In turn, WT but not ST2(-/-) MCs augmented fibroblast expression of IL-33, forming a positive feedback circuit. Together, these findings confirm a novel role for IL-33 as an amplifier of IgG immune complex-mediated inflammation and identify a potential MC-fibroblast amplification loop dependent on IL-33 and ST2.

Interleukin 33 as a mechanically responsive cytokine secreted by living cells.

Interleukin 33 (IL-33), a member of the Interleukin 1 cytokine family, is implicated in numerous human inflammatory diseases such as asthma, atherosclerosis, and rheumatoid arthritis. Despite its pathophysiologic importance, fundamental questions regarding the basic biology of IL-33 remain. Nuclear localization and lack of an export signal sequence are consistent with the view of IL-33 as a nuclear factor with the ability to repress RNA transcription. However, signaling via the transmembrane receptor ST2 and documented caspase-dependent inactivation have suggested IL-33 is liberated during cellular necrosis to effect paracrine signaling. We determined the subcellular localization of IL-33 and tracked its intracellular mobility and extracellular release. In contrast to published data, IL-33 localized simultaneously to nuclear euchromatin and membrane-bound cytoplasmic vesicles. Fluorescent pulse-chase fate-tracking documented dynamic nucleo-cytoplasmic flux, which was dependent on nuclear pore complex function. In murine fibroblasts in vitro and in vivo, mechanical strain induced IL-33 secretion in the absence of cellular necrosis. These data document IL-33 dynamic inter-organelle trafficking and release during biomechanical overload. As such we recharacterize IL-33 as both an inflammatory as well as mechanically responsive cytokine secreted by living cells.