Exploring verbal and physical workplace violence in a large, urban emergency department.

BACKGROUND: Violence directed at healthcare workers (HCWs) is common and may be more frequent in the emergency department (ED). In addition to physical injury, other consequences of workplace violence in the ED include an increased risk of burnout, post-traumatic stress disorder, reduced job satisfaction, and feelings of avoidance and futility. Understanding behaviors underlying workplace violence is the first step to employing mitigation strategies. The objective of this descriptive study was to assess the prevalence and types of violence against HCWs in a large, urban ED. METHODS: This study took place in the ED of an urban hospital with an annual ED census of approximately 100,000. A previously existing general patient safety incident "dropbox" for HCWs was utilized to capture workplace violence reports. At the completion of the study period, all data was collated into the electronic database and each report was categorized based on the nature and severity of the abuse. Further, all events were also coded as either involving or not involving specifically racist, sexist, or homophobic content. The primary outcomes were the number of reported events over the study period, and the percentage of total events that fell into each category. The secondary outcomes were the overall prevalence and ratio of events that included racist, sexist, or homophobic language or provocation. RESULTS: Over the 5-month survey period, 130 reports of workplace violence were recorded, on average 0.85 per day. Perpetrators were mostly male, and most victims were nurses. Hospital security was involved in 26% of cases. At least 37% of incidents involved patients that were intoxicated and/or had history of psychiatric illness. Type I events (swearing provocatively, shouting, and legal threats) were the most common at 44% of encounters while 22% involved physical violence. Racist, sexist, and homophobic comments were involved in 8 (6%), 18 (14%), and 3 (2%) incidents respectively. CONCLUSION: We found that workplace violence against HCWs was common in this study, and sometimes involved a component of racist, sexist, or homophobic bias. Consistent with previous ED literature, we found that abusive events occurred almost daily and that approximately 20% of events involved physical violence. Future efforts toward policy change to address workplace violence in health care is needed at local, state, and national levels.

Role of environmental and antibiotic stress on Staphylococcus epidermidis biofilm microstructure.

Cellular clustering and separation of Staphylococcus epidermidis surface adherent biofilms were found to depend significantly on both antibiotic and environmental stress present during growth under steady flow. Image analysis techniques common to colloidal science were applied to image volumes acquired with high-resolution confocal laser scanning microscopy to extract spatial positions of individual bacteria in volumes of size ~30 × 30 × 15 µm(3). The local number density, cluster distribution, and radial distribution function were determined at each condition by analyzing the statistics of the bacterial spatial positions. Environmental stressors of high osmotic pressure (776 mM NaCl) and sublethal antibiotic dose (1.9 µg/mL vancomycin) decreased the average bacterial local number density 10-fold. Device-associated bacterial biofilms are frequently exposed to these environmental and antibiotic stressors while undergoing flow in the bloodstream. Characteristic density phenotypes associated with low, medium, and high local number densities were identified in unstressed S. epidermidis biofilms, while stressed biofilms contained medium- and low-density phenotypes. All biofilms exhibited clustering at length scales commensurate with cell division (~1.0 µm). However, density phenotypes differed in cellular connectivity at the scale of ~6 µm. On this scale, nearly all cells in the high- and medium-density phenotypes were connected into a single cluster with a structure characteristic of a densely packed disordered fluid. However, in the low-density phenotype, the number of clusters was greater, equal to 4% of the total number of cells, and structures were fractal in nature with d(f) =1.7 ± 0.1. The work advances the understanding of biofilm growth, informs the development of predictive models of transport and mechanical properties of biofilms, and provides a method for quantifying the kinetics of bacterial surface colonization as well as biofilm fracture and fragmentation.

Molar mass, entanglement, and associations of the biofilm polysaccharide of Staphylococcus epidermidis.

Biofilms are microbial communities that are characterized by the presence of a viscoelastic extracellular polymeric substance (EPS). Studies have shown that polysaccharides, along with proteins and DNA, are a major constituent of the EPS and play a dominant role in mediating its microstructure and rheological properties. Here, we investigate the possibility of entanglements and associative complexes in solutions of extracellular polysaccharide intercellular adhesin (PIA) extracted from Staphylococcus epidermidis biofilms. We report that the weight average molar mass and radius of gyration of PIA isolates are 2.01×10(5)±1200 g/mol and 29.2±1.2 nm, respectively. The coil overlap concentration, c*, was thus determined to be (32±4)×10(-4) g/mL. Measurements of the in situ concentration of PIA (cPIA,biofilm) was found to be (10±2)×10(-4) g/mL.Thus, cPIA,biofilm

Multilocus Sequence Typing for Interpreting Blood Isolates of Staphylococcus epidermidis.

Staphylococcus epidermidis is an important cause of nosocomial infection and bacteremia. It is also a common contaminant of blood cultures and, as a result, there is frequently uncertainty as to its diagnostic significance when recovered in the clinical laboratory. One molecular strategy that might be of value in clarifying the interpretation of S. epidermidis identified in blood culture is multilocus sequence typing. Here, we examined 100 isolates of this species (50 blood isolates representing true bacteremia, 25 likely contaminant isolates, and 25 skin isolates) and the ability of sequence typing to differentiate them. Three machine learning algorithms (classification regression tree, support vector machine, and nearest neighbor) were employed. Genetic variability was substantial between isolates, with 44 sequence types found in 100 isolates. Sequence types 2 and 5 were most commonly identified. However, among the classification algorithms we employed, none were effective, with CART and SVM both yielding only 73% diagnostic accuracy and nearest neighbor analysis yielding only 53% accuracy. Our data mirror previous studies examining the presence or absence of pathogenic genes in that the overlap between truly significant organisms and contaminants appears to prevent the use of MLST in the clarification of blood cultures recovering S. epidermidis.

Complement c5a generation by staphylococcal biofilms.

Biofilms production is a central feature of nosocomial infection of catheters and other medical devices used in resuscitation and critical care. However, the very effective biofilm forming pathogen Staphylococcus epidermidis often produces a modest host inflammatory response and few of the signs and symptoms associated with more virulent pathogens. To examine the impact of bacterial biofilm formation on provocation of an innate immune response, we studied the elaboration of the major complement anaphylatoxin C5a by human serum upon contact with S. epidermidis biofilms. Wild-type S. epidermidis and mutants of sarA (a regulatory protein that promotes synthesis of the biofilm-forming polysaccharide intercellular adhesin [PIA]) and icaB (responsible for postexport processing of PIA) were studied. C5a release, as a function of exposed biofilm surface area, was on the order of 1 fmol · cm · s and was dependent on the presence of PIA. Experimental results were used to inform a physiologically based pharmacokinetic model of C5a release by an infected central venous catheter, one of S. epidermidis' primary means of causing human disease. These simulations revealed that the magnitude of C5a release on a superior vena cava catheter completely covered with S. epidermidis would be lower than necessary to alert circulating leukocytes. Combined, the experimental and computational results are highly consistent with clinical observations in which the clinical signs of central line-associated bloodstream infection are often muted in association with this important pathogen.