572. Relationship Between Chlorhexidine Gluconate (CHG) Skin Concentrations and Microbial Skin Colonization among Medical Intensive Care Unit (MICU) Patients

Abstract Background CHG bathing is used to suppress patients’ microbial skin colonization, in order to prevent infections and transmission of multidrug-resistant organisms. Prior work has suggested that microbial growth is inhibited when CHG skin concentrations exceed threshold levels. Methods We conducted 6 single-day surveys from January 2018 to February 2019 in 7 academic hospital MICUs with established CHG patient bathing. Adult patients were eligible to have skin swabbed from adjacent 25 cm2 areas on the neck, axilla, and inguinal region for culture and CHG concentration determination. CHG skin concentrations were measured by a semi-quantitative colorimetric assay. Selective media were used to isolate targeted microorganisms (Table 1). Species were confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry; antibiotic susceptibility was determined by MicroScan (Beckman Coulter). We modeled the relationship between CHG skin concentrations (log2-transformed) and microorganism recovery (yes/no as primary outcome) using multilevel models controlling for clustering of body sites within patients and within ICUs, assessing slope and threshold effects. Results We enrolled 736/759 (97%) patients and sampled 2176 skin sites. Gram-positive bacteria were detected most frequently (Table 1). The adjusted odds of identifying gram-positive organisms decreased linearly as CHG skin levels increased (Figure 1a), without evidence of a threshold effect. We also found significant negative linear slopes without evidence of threshold effects for other pathogens tested (Table 2; Figure 1), with the exception of gram-negative bacteria and vancomycin-resistant enterococci. When modeling quantitative culture results (colony-forming units) for gram-positive organisms as a continuous outcome variable, a similar relationship was found. Conclusion Higher concentrations of CHG were associated with less frequent recovery of gram-positive bacteria and Candida species on the skin of MICU patients who were bathed routinely with CHG. For microbial inhibition, we did not identify a threshold concentration of CHG on the skin; rather, increasing CHG skin concentrations led to additional gains in inhibition. For infection prevention, aiming for high CHG skin levels may be beneficial. Disclosures All authors: No reported disclosures

895. Impact of Measurement and Results Feedback of Chlorhexidine Gluconate (CHG) Skin Concentrations in Medical Intensive Care Unit (MICU) Patients Receiving CHG Bathing

Abstract Background Higher CHG skin levels may be needed to adequately control infection and transmission of pathogens in the ICU. We assessed whether measurement and feedback of patient CHG skin concentrations could improve CHG bathing quality and identified factors associated with higher CHG skin concentrations. Methods We conducted 6 one-day surveys from January 2018 to February 2019 in 7 academic hospital MICUs with established daily CHG bathing. Adults admitted >1 day were assessed for CHG skin levels with a semi-quantitative colorimetric assay using swabbed 25 cm2 areas of anterior neck, axilla, and inguinal skin. Prior to survey 4, results from the first 3 surveys (baseline) were reported to ICU leadership and front-line staff to retrain and reeducate on bathing technique. Feedback of results from prior surveys also occurred before surveys 5 and 6. For statistical analysis, mixed-effects models accounted for clustering of CHG measurements within patients and ICUs. We categorized CHG product type as “cloth” for no-rinse 2% CHG-impregnated cloth and “liquid” for 4% CHG liquid or foam. Results In total, 681 of 704 (97%) patients were enrolled. Three ICUs used CHG cloth, 3 ICUs used CHG liquid, and 1 ICU switched from liquid to cloth after the second survey. Median CHG skin concentrations were higher in both the baseline and feedback period for institutions using CHG cloth, as compared with liquid (table). Across all time points, axillary and inguinal regions had higher skin CHG concentrations than the neck (median 39.1, 78.1, 19.5 µg/mL, respectively, P < 0.001). After controlling for age, mechanical ventilation, presence of a central venous catheter, body site, and hours since last CHG bath, institutions that used CHG cloth had a 3-fold increase in adjusted CHG skin concentrations in the feedback period compared with the baseline period (P = 0.001, Figure). There was no significant change in CHG skin concentrations from baseline to feedback period for institutions that used liquid CHG. Conclusion CHG skin concentrations on MICU patients receiving daily CHG bathing varied by body site and CHG product type. The use of CHG cloth was associated with higher CHG skin levels, compared with CHG liquid. For ICUs using CHG cloth, feedback of CHG skin concentration results to ICU staff improved CHG bathing quality. Disclosures All Authors: No reported Disclosures

Impact of measurement and feedback on chlorhexidine gluconate bathing among intensive care unit patients: A multicenter study.

OBJECTIVE: To assess whether measurement and feedback of chlorhexidine gluconate (CHG) skin concentrations can improve CHG bathing practice across multiple intensive care units (ICUs). DESIGN: A before-and-after quality improvement study measuring patient CHG skin concentrations during 6 point-prevalence surveys (3 surveys each during baseline and intervention periods). SETTING: The study was conducted across 7 geographically diverse ICUs with routine CHG bathing. PARTICIPANTS: Adult patients in the medical ICU. METHODS: CHG skin concentrations were measured at the neck, axilla, and inguinal region using a semiquantitative colorimetric assay. Aggregate unit-level CHG skin concentration measurements from the baseline period and each intervention period survey were reported back to ICU leadership, which then used routine education and quality improvement activities to improve CHG bathing practice. We used multilevel linear models to assess the impact of intervention on CHG skin concentrations. RESULTS: We enrolled 681 (93%) of 736 eligible patients; 92% received a CHG bath prior to survey. At baseline, CHG skin concentrations were lowest on the neck, compared to axillary or inguinal regions (P < .001). CHG was not detected on 33% of necks, 19% of axillae, and 18% of inguinal regions (P < .001 for differences in body sites). During the intervention period, ICUs that used CHG-impregnated cloths had a 3-fold increase in patient CHG skin concentrations as compared to baseline (P < .001). CONCLUSIONS: Routine CHG bathing performance in the ICU varied across multiple hospitals. Measurement and feedback of CHG skin concentrations can be an important tool to improve CHG bathing practice

Cardiovascular disease and cognitive dysfunction in systemic lupus erythematosus.

ObjectiveCognitive dysfunction and cardiovascular disease are common and debilitating manifestations of systemic lupus erythematosus (SLE). In this study, we evaluated the relationship between cardiovascular events, traditional cardiovascular risk factors, and SLE-specific risk factors as predictors of cognitive dysfunction in a large cohort of participants with SLE.MethodsSubjects included 694 participants from the Lupus Outcomes Study (LOS), a longitudinal study of SLE outcomes based on an annual telephone survey querying demographic and clinical variables. The Hopkins Verbal Learning Test-Revised and the Controlled Oral Word Association Test were administered to assess cognitive function. Multiple logistic regression was used to identify cardiovascular events (myocardial infarction, stroke), traditional cardiovascular risk factors (hypertension, hyperlipidemia, diabetes mellitus, obesity, smoking), and SLE-specific risk factors (antiphospholipid antibodies [aPL], disease activity, disease duration) associated with cognitive impairment in year 7 of the LOS.ResultsThe prevalence of cognitive impairment as measured by verbal memory and verbal fluency metrics was 15%. In adjusted multiple logistic regression analyses, aPL (odds ratio [OR] 2.10, 95% confidence interval [95% CI] 1.3-3.41), hypertension (OR 2.06, 95% CI 1.19-3.56), and a history of stroke (OR 2.27, 95% CI 1.16-4.43) were significantly associated with cognitive dysfunction. In additional analyses evaluating the association between these predictors and severity of cognitive impairment, stroke was significantly more prevalent in participants with severe impairment when compared to those with mild or moderate impairment (P = 0.036).ConclusionThese results suggest that the presence of aPL, hypertension, and stroke are key variables associated with cognitive impairment, which may aid in identification of patients at greatest risk

Minimizing treatment-induced emergence of antibiotic resistance in bacterial infections

Treatment of bacterial infections currently focuses on choosing an antibiotic that matches a pathogen’s susceptibility, with less attention paid to the risk that even susceptibility-matched treatments can fail as a result of resistance emerging in response to treatment. Combining whole-genome sequencing of 1113 pre- and posttreatment bacterial isolates with machine-learning analysis of 140,349 urinary tract infections and 7365 wound infections, we found that treatment-induced emergence of resistance could be predicted and minimized at the individual-patient level. Emergence of resistance was common and driven not by de novo resistance evolution but by rapid reinfection with a different strain resistant to the prescribed antibiotic. As most infections are seeded from a patient’s own microbiota, these resistance-gaining recurrences can be predicted using the patient’s past infection history and minimized by machine learning–personalized antibiotic recommendations, offering a means to reduce the emergence and spread of resistant pathogens

An evaluation of molecular and clinical remission in rheumatoid arthritis by assessing radiographic progression

Objectives. To determine whether molecular remission defined by a multi-biomarker disease activity (MBDA) score predicts a reduced risk of joint damage progression, and whether the MBDA score can augment existing classifications of remission. Methods. The study examined 271 visits for 163 RA patients in the Leiden Early Arthritis Cohort. The MBDA score and other variables from each visit were evaluated for prediction of progression [change in Sharp–van der Heijde Score (ΔSHS) >3] over the ensuing 12 months. Positive likelihood ratios (PLRs) for non-progression were calculated for remission based upon DAS based on 28-joint counts and CRP (DAS28-CRP <2.32), EULAR/ACR Boolean criteria and MBDA score (≤25). Results. Ninety-three per cent of patients in MBDA-defined remission did not experience progression, compared with 70% of patients not in MBDA remission (P = 0.001). There were no significant differences in the fraction of non-progressers between patients in remission and those not in remission using either DAS28-CRP or EULAR/ACR criteria. The PLR for non-progression over 12 months for MBDA remission was 4.73 (95% CI 1.67, 15.0). Among patients in DAS28-CRP remission, those with a high MBDA score were 2.3 times as likely (95% CI 1.1, 3.7) to have joint damage progression during the next year. Conclusion. MBDA-defined remission was an indicator of limited radiographic progression over the following 12 months. For patients in DAS28-CRP remission, high MBDA scores were a significant indicator of elevated risk of progression. MBDA results may provide a useful adjunct to clinical assessment to identify progression-free remission and assess subclinical disease

Evolthon: A community endeavor to evolve lab evolution.

In experimental evolution, scientists evolve organisms in the lab, typically by challenging them to new environmental conditions. How best to evolve a desired trait? Should the challenge be applied abruptly, gradually, periodically, sporadically? Should one apply chemical mutagenesis, and do strains with high innate mutation rate evolve faster? What are ideal population sizes of evolving populations? There are endless strategies, beyond those that can be exposed by individual labs. We therefore arranged a community challenge, Evolthon, in which students and scientists from different labs were asked to evolve Escherichia coli or Saccharomyces cerevisiae for an abiotic stress-low temperature. About 30 participants from around the world explored diverse environmental and genetic regimes of evolution. After a period of evolution in each lab, all strains of each species were competed with one another. In yeast, the most successful strategies were those that used mating, underscoring the importance of sex in evolution. In bacteria, the fittest strain used a strategy based on exploration of different mutation rates. Different strategies displayed variable levels of performance and stability across additional challenges and conditions. This study therefore uncovers principles of effective experimental evolutionary regimens and might prove useful also for biotechnological developments of new strains and for understanding natural strategies in evolutionary arms races between species. Evolthon constitutes a model for community-based scientific exploration that encourages creativity and cooperation