Aqueous Ozone Exposure Inhibits Sporulation in the Cyclospora cayetanensis Surrogate Eimeria acervulina.

Ozone is a potent disinfecting agent used to treat potable water and wastewater, effectively clearing protozoa such as Giardia and Cryptosporidium spp. It is unclear whether ozone treatment of water or fresh produce can reduce the spread of the emerging parasite Cyclospora cayetanensis, which causes cyclosporiasis in humans. Obtaining viable C. cayetanensis oocysts to evaluate inactivation methods is challenging because we lack the means to propagate them in vitro, because of delays in case reporting, and because health departments typically add inactivating fixatives to clinical specimens. Research in various surrogate organisms has sought to bolster understanding of the biology of C. cayetanensis. Among these surrogates is the poultry parasite Eimeria acervulina, a closely related and easily cultured parasite of economic significance. We used this surrogate to evaluate the consequences of ozone treatment, using the sporulation state as an indicator of infectious potential. Treating with ozonated water acidified with citric acid reduced sporulation ability in a dose-dependent manner; treatment with up to 4.93 mg/L initial concentration of ozone resulted in a 93% inactivation of sporulation by 7 days posttreatment. This developmental arrest was accompanied by transcriptional changes in genes involved in regulating the response to reactive oxygen species (ROS) in a time course that is consistent with the production of oxygen free radicals. This study shows that ozone is highly effective in preventing sporulation of E. acervulina, a model coccidian used as a surrogate for Cyclospora. Furthermore, ozone exposure induced molecular responses to general oxidative stress, documented with several well-characterized antioxidant enzymes.

Host Microbiome Threats in the Intensive Care Unit.

Human microbiota demonstrate diversity and balance that is adaptive for the host and supports maintaining homeostasis. Although acute illness or injury may derange microbiota diversity and the proportion of potentially pathogenic microbes, that derangement may be further exacerbated by commonly deployed intensive care unit (ICU) therapeutic and practices. These include antibiotic administration, delayed luminal nutrition, acid suppression, and vasopressor infusion. Furthermore, the local ICU microbial ecology, regardless of disinfection practices, shapes the patient's microbiota, especially with the acquisition of multi-drug-resistant pathogens. Current approaches to protect a normal microbiome, or restore a deranged one, are part of a multifaceted approach that may include antibiotic stewardship and infection control practices as microbiome-directed therapeutics emerge.

Simulation of the VUV Absorption Spectra of Oxygenates and Hydrocarbons: A Joint Theoretical-Experimental Study.

Vacuum UV absorption spectroscopy is regularly used to provide unambiguous identification of a target species, insight into the electronic structure of molecules, and quantitative species concentrations. As molecules of interest have become more complex, theoretical spectra have been used in tandem with laboratory spectroscopic analysis or as a replacement when experimental data is unavailable. However, it is difficult to determine which theoretical methodologies can best simulate experiment. This study examined the performance of EOM-CCSD and 10 TD-DFT functionals (B3LYP, BH&HLYP, BMK, CAM-B3LYP, HSE, M06-2X, M11, PBE0, ωB97X-D, and X3LYP) to produce reliable vacuum UV absorption spectra for 19 small oxygenates and hydrocarbons using vertical excitation energies. The simulated spectra were analyzed against experiment using both a qualitative analysis and quantitative metrics, including cosine similarity, relative integral change, mean signed error, and mean absolute error. Based on our ranking system, it was determined that M06-2X was consistently the top performing TD-DFT method with BMK, CAM-B3LYP, and ωB97X-D also producing reliable spectra for these small combustion species.

Sepsis and postoperative surgical site infections.

Surgical site infections remain a significant cause of morbidity and mortality. High-quality evidence supports several measures to prevent surgical site infections that should be applied with high compliance, although effective application remains suboptimal. Recognizing high-risk patients and avoiding potential pitfalls in the diagnosis of surgical site infections is paramount in preventing progression to sepsis, particularly in emergency surgical patients with physiologic derangement. A high index of suspicion postoperatively is critical to identify patients with surgical site infections and to prevent failure to rescue.

Emergency General Surgery Regionalization: Retrospective Cohort Study of Emergency General Surgery Patients at a Tertiary Care Center.

BACKGROUND: Emergency general surgery (EGS) patients presenting at tertiary care hospitals may bypass local hospitals with adequate resources. However, many tertiary care hospitals frequently operate at capacity. We hypothesized that understanding patient geographic origin could identify opportunities for enhanced system triage and optimization and be an important first step for EGS regionalization and care coordination that could potentially lead to improved utilization of resources. METHODS: We analyzed patient zip code and categorized EGS patients who were cared for at our tertiary care hospital as potentially divertible if the southern region hospital was geographically closer to their home, regional hospital admission (RHA) patients, or local admission (LA) patients if the tertiary care facility was closer. Baseline characteristics and outcomes were compared for RHA and LA patients. RESULTS: Of 14 714 EGS patients presenting to the tertiary care hospital, 30.2% were categorized as RHA patients. Overall, 1526 (10.4%) patients required an operation including 527 (34.5%) patients who were potentially divertible. Appendectomy and cholecystectomy comprised 66% of the operations for potentially divertible patients. Length of stay was not significantly different (P = .06) for RHA patients, but they did have lower measured short-term and long-term mortality when compared to their LA counterparts (P < .05). CONCLUSIONS: EGS diagnoses and patient geocode analysis can identify opportunities to optimize regional operating room and bed utilization. Understanding where EGS patients are cared for and factors that influenced care facility will be critical for next steps in developing EGS regionalization within our system.

Emergencies do not shut down during a pandemic: COVID pandemic impact on Acute Care Surgery volume and mortality at a level I trauma center.

BACKGROUND: The aim of this study was to evaluate the impact of the COVID-19 pandemic on volume and outcomes of Acute Care Surgery patients, and we hypothesized that inpatient mortality would increase due to COVID+ and resource constraints. METHODS: An American College of Surgeons verified Level I Trauma Center's trauma and operative emergency general surgery (EGS) registries were queried for all patients from Jan. 2019 to Dec. 2020. April 1st, 2020, was the demarcation date for pre- and during COVID pandemic. Primary outcome was inpatient mortality. RESULTS: There were 14,460 trauma and 3091 EGS patients, and month-over-month volumes of both remained similar (p > 0.05). Blunt trauma decreased by 7.4% and penetrating increased by 31%, with a concomitant 25% increase in initial operative management (p < 0.001). Despite this, trauma (3.7%) and EGS (2.9-3.0%) mortality rates remained stable which was confirmed on multivariate analysis; p > 0.05. COVID + mortality was 8.8% and 3.7% in trauma and EGS patients, respectively. CONCLUSION: Acute Care Surgeons provided high quality care to trauma and EGS patients during the pandemic without allowing excess mortality despite many hardships and resource constraints.

The physiology of failure: Identifying risk factors for mortality in emergency general surgery patients using a regional health system integrated electronic medical record.

BACKGROUND: Emergency general surgery (EGS) patients have increased mortality risk compared with elective counterparts. Recent studies on risk factors have largely used national data sets limited to administrative data. Our aim was to examine risk factors in an integrated regional health system EGS database, including clinical and administrative data, hypothesizing that this novel process would identify clinical variables as important risk factors for mortality. METHODS: Our nine-hospital health system's billing data were queried for EGS International Classification of Disease codes between 2013 and 2018. Codes were grouped by diagnosis, and urgent or emergent encounters were included and merged with electronic medical record clinical data. Outcomes assessed were inpatient and 1-year mortality. Standard and multivariable statistics evaluated factors associated with mortality. RESULTS: There were 253,331 EGS admissions with 3.6% inpatient mortality rate. Patients who suffered inpatient and 1-year mortality were older, more likely to be underweight, and have neutropenia or elevated lactate. On multivariable analysis for inpatient mortality: age (odds ratio [OR], 1.7-6.7), underweight body mass index (OR, 1.6), transfer admission (OR, 1.8), leukopenia (OR, 2.0), elevated lactate (OR, 1.8), and ventilator requirement (OR, 7.1) remained associated with increased risk. Adjusted analysis for 1-year mortality demonstrated similar findings, with highest risk associated with older age (OR, 2.8-14.6), underweight body mass index (OR, 2.3), neutropenia (OR, 2.0), and tachycardia (OR, 1.7). CONCLUSION: After controlling for patient and disease characteristics available in administrative databases, clinical variables remained significantly associated with mortality. This novel yet simple process allows for easy identification of clinical data points imperative to the study of EGS diagnoses that are critical in understanding factors that impact mortality. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level III.

Prior Antibiotic Exposure Is Associated With Reoperation After Elective Non-colorectal Surgery.

BACKGROUND: Recent antibiotic exposure has previously been associated with poor outcomes following elective surgery. The purpose of this study is to evaluate the impact of prior recent antibiotic exposure in a multicenter cohort of Veterans Affairs patients undergoing elective non-colorectal surgery. METHODS: This is a retrospective cohort study of the Veterans Affairs Surgical Quality Improvement Program, including elective, non-cardiovascular, non-colorectal surgery from 2013 to 2017. Outpatient antibiotic exposure within 90 days prior to surgery was identified from the Veterans Affairs outpatient pharmacy database and matched with each case. Primary outcomes included serious complication, any complication, any infection, or surgical site infection. Secondary outcomes included 30-day mortality, length of stay, and Clostridioides difficile infection. RESULTS: Of 21,112 eligible patients, 2885 (13.7%) were exposed to antibiotics within 90 days prior to surgery with a duration of 7 (IQR: 5-10) days and prescribed 42 (IQR: 21-64) days prior to surgical intervention. Compared to non-exposed patients, exposed patients had higher unadjusted complication rates, increased length of stay, and rates of return to the operating. Exposure was independently associated with return to the operating room (OR: 1.39; 99% CI: 1.05-1.84). CONCLUSIONS: Among Veterans, recent antibiotic exposure within 90 days of elective surgery was associated with a 39% increase in the odds of return to the operating room. Further work is needed to evaluate the effects of antibiotic exposure and dysbiosis on surgical outcomes.

Effect of Antibiotic Duration in Emergency General Surgery Patients with Intra-Abdominal Infection Managed with Open vs Closed Abdomen.

BACKGROUND: Data on duration of antibiotics in patients managed with an open abdomen (OA) due to intra-abdominal infection (IAI) are scarce. We hypothesized that patients with IAI managed with OA rather than closed abdomen (CA) would have higher rates of secondary infections (SIs) independent of the duration of the antibiotic treatment. METHODS: This was an observational, prospective, multicenter, international study of patients with IAI requiring laparotomy for source control. Demographic and antibiotic duration values were collected. Primary outcomes were SI (surgical site, bloodstream, pneumonia, urinary tract) and mortality. Statistical analysis included ANOVA, chi-square/Fisher's exact test, and logistic regression. RESULTS: Twenty-one centers contributed 752 patients. The average age was 59.6 years, 43.6% were women, and 43.9% were managed with OA. Overall mortality was 16.1%, with higher rates among OA patients (31.6% vs 4.4%, p < 0.001). OA patients had higher Sequential Organ Failure Assessment (4.7 vs 1.8, p < 0.001), American Society of Anesthesiologists Physical Status (3.6 vs 2.7, p < 0.001), and APACHE II scores (16.1 vs 9.4, p < 0.001). The mean duration of antibiotics was 6.5 days (8.0 OA vs 5.4 CA, p < 0.001). A total of 179 (23.8%) patients developed SI (33.1% OA vs 16.8% CA, p < 0.001). Longer antibiotic duration was associated with increased rates of SI: 1 to 2 days, 15.8%; 3 to 5 days, 20.4%; 6 to 14 days, 26.6%; and more than 14 days, 46.8% (p < 0.001). CONCLUSIONS: Patients with IAI managed with OA had higher rates of SI and increased mortality compared with CA. A prolonged duration of antibiotics was associated with increased rates of SI. Increased antibiotic duration is not associated with improved outcomes in patients with IAI and OA.

Assessing the predictive capabilities of design heuristics and coarse-grain simulation toward understanding and optimizing site-specific covalent immobilization of ß-lactamase.

For industrial applications, covalent immobilization of enzymes provides minimum leakage, recoverability, reusability, and high stability. Yet, the suitability of a given site on the enzyme for immobilization remains a trial-and-error procedure. Here, we investigate the reliability of design heuristics and a coarse-grain molecular simulation in predicting the optimum sites for covalent immobilization of TEM-1 ß-lactamase. We utilized Escherichia coli-lysate-based cell-free protein synthesis (CFPS) to produce variants containing a site-specific incorporated unnatural amino acid with a unique moiety to facilitate site directed covalent immobilization. To constrain the number of potential immobilization sites, we investigated the predictive capability of several design heuristics. The suitability of immobilization sites was determined by analyzing expression yields, specific activity, immobilization efficiency, and stability of variants. These experimental findings are compared with coarse-grain simulation of TEM-1 domain stability and thermal stability and analyzed for a priori predictive capabilities. This work demonstrates that the design heuristics successfully identify a subset of locations for experimental validation. Specifically, the nucleotide following amber stop codon and domain stability correlate well with the expression yield and specific activity of the variants, respectively. Our approach highlights the advantages of combining coarse-grain simulation and high-throughput experimentation using CFPS to identify optimal enzyme immobilization sites.

Assessing site-specific PEGylation of TEM-1 ß-lactamase with cell-free protein synthesis and coarse-grained simulation.

PEGylation is a broadly used strategy to enhance the pharmacokinetic properties of therapeutic proteins. It is well established that the location and extent of PEGylation have a significant impact on protein properties. However, conventional PEGylation techniques have limited control over PEGylation sites. Emerging site-specific PEGylation technology provides control of PEG placement by conjugating PEG polymers via click chemistry reaction to genetically encoded non-canonical amino acids. Unfortunately, a method to rapidly determine the optimal PEGylation location has yet to be established. Here we seek to address this challenge. In this work, coarse-grained molecular dynamic simulations are paired with high-throughput experimental screening utilizing cell-free protein synthesis to investigate the effect of site-specific PEGylation on the two-state folder protein TEM-1 ß-lactamase. Specifically, the conjugation efficiency, thermal stability, and enzymatic activity are studied for the enzyme PEGylated at several different locations. The results of this analysis confirm that the physical properties of the PEGylated protein vary considerably with PEGylation site and that traditional design recommendations are insufficient to predict favorable PEGylation sites. In this study, the best predictor of the most favorable conjugation site is coarse-grained simulation. Thus, we propose a dual combinatorial screening approach in which coarse-grained molecular simulation informs site selection for high-throughput experimental verification.

Laparoscopy is associated with decreased all-cause mortality in patients undergoing emergency general surgery procedures in a regional health system.

BACKGROUND: The aim of this study was to evaluate the use of laparoscopic surgery for common emergency general surgery (EGS) procedures within an integrated Acute Care Surgery (ACS) network. We hypothesized that laparoscopy would be associated with improved outcomes. METHODS: Our integrated health care system's EGS registry created from AAST EGS ICD-9 codes was queried from January 2013 to October 2015. Procedures were grouped as laparoscopic or open. Standard descriptive and univariate tests were performed, and a multivariable logistic regression controlling for open status, age, BMI, Charlson Comorbidity Index (CCI), trauma tier, and resuscitation diagnosis was performed. Laparoscopic procedures converted to open were identified and analyzed using concurrent procedure billing codes across episodes of care. RESULTS: Of 60,604 EGS patients identified over the 33-month period, 7280 (12.0%) had an operation and 6914 (11.4%) included AAST-defined EGS procedures. There were 4813 (69.6%) surgeries performed laparoscopically. Patients undergoing a laparoscopic procedure tended to be younger (45.7 ± 18.0 years vs. 57.2 ± 17.6, p < 0.001) with similar BMI (29.7 ± 9.0 kg/m2 vs. 28.8 ± 8.3, p < 0.001). Patients in the laparoscopic group had lower mean CCI score (1.6 ± 2.3 vs. 3.4 ± 3.2, p ≤ 0.0001). On multivariable analysis, open surgery had the highest association with inpatient mortality (OR 8.67, 4.23-17.75, p < 0.0001) and at all time points (30-, 90-day, 1-, 3-year). At all time points, conversion to open was found to be a statistically significant protective factor. CONCLUSION: Use of laparoscopy in EGS is common and associated with a decreased risk of all-cause mortality at all time points compared to open procedures. Conversion to open was protective at all time points compared to open procedures.

The Obesity Paradox in Emergency General Surgery Patients.

BACKGROUND: Operative management of emergency general surgery (EGS) diagnoses involves a range of procedures which can carry high morbidity and mortality. Little is known about the impact of obesity on patient outcomes. The aim of this study was to examine the association between body mass index (BMI) >30 kg/m2 and mortality for EGS patients. We hypothesized that obese patients would have increased mortality rates. METHODS: A regional integrated health system EGS registry derived from The American Association for the Surgery of Trauma EGS ICD-9 codes was analyzed from January 2013 to October 2015. Patients were stratified into BMI categories based on WHO classifications. The primary outcome was 30-day mortality. Longer-term mortality with linkage to the Social Security Death Index was also examined. Univariate and multivariable analyses were performed. RESULTS: A total of 60 604 encounters were identified and 7183 (11.9%) underwent operative intervention. Patient characteristics include 53% women, mean age 58.2 ± 18.7 years, 64.2% >BMI 30 kg/m2, 30.2% with chronic obstructive pulmonary disease, 19% with congestive heart failure, and 31.1% with diabetes. The most common procedure was laparoscopic cholecystectomy (36.4%). Overall, 90-day mortality was 10.9%. In multivariable analysis, all classes of obesity were protective against mortality compared to normal BMI. Underweight patients had increased risk of inpatient (OR = 1.9, CI = 1.7-2.3), 30-day (OR = 1.9, CI = 1.7-2.1), 90-day (OR = 1.8, CI 1.6-2.0), 1-year (OR = 1.8, CI = 1.7-2.0), and 3-year mortality (OR = 1.7, CI = 1.6-1.9). CONCLUSIONS: When stratified by BMI, underweight EGS patients have the highest odds of death. Paradoxically, obesity appears protective against death, even when controlling for potentially confounding factors. Increased rates of nonoperative management in the obese population may impact these findings.

Parsing Intra- and Inter-Individual Covariation Between the Sensory Attributes and Appeal of E-Cigarettes: Associations and Gender Differences.

INTRODUCTION: Perceived sensory attributes of e-cigarettes may associate with their appeal. However, limited studies have accounted for individuals' variability in sensory attributes or have addressed how associations of sensory attributes with appeal may differ by gender. METHODS: Individuals (n = 119, 32.8% female) who currently used combustible cigarettes and/or e-cigarettes attended one laboratory session in which they completed a standardized e-cigarette puffing procedure according to a 10 Flavor (green apple, strawberry, chocolate, vanilla, menthol, koolada, peppermint, spearmint, subtle tobacco, and full-flavored tobacco) × 2 Nicotine Formulation (free-base, salt) double-blind factorial design. The mean nicotine concentration was 23.4 (SD = 0.9) mg/mL in the nicotine salt formulations and 23.8 (SD = 1.7) mg/mL in the free-base formulations. Following each trial, participants completed ratings of sensory attributes (sweet, smooth, cool, bitter, harsh) and appeal (mean of liking, disliking [reverse-scored], and willingness-to-use-again ratings). Sensory attributes were partitioned into between-person and within-person variables. Gender was tested as a moderator of associations of sensory attributes with appeal. RESULTS: Sweet, smooth, and cool sensory attributes positively associated with appeal at the between- and within-person level (ps < .001). Bitter and harsh negatively associated with appeal at the between- and within-person level (ps < .001). The associations of between-person sweet, smooth, and cool ratings with appeal was larger in males compared to females. The associations of within-person smooth, bitter, and harsh with appeal was larger in females compared to males. CONCLUSIONS: This study showed important gender differences in associations of sensory attributes and appeal. IMPLICATIONS: While evidence suggests that sensory attributes may contribute to the appeal of e-cigarettes, there is little experimental evidence accounting for individual variability in sensory attributes and whether sensory attribute-appeal associations differ by gender. The current study provides evidence that average sweet, cool, and smooth ratings positively associated with appeal and that these associations were larger in males. Within-person bitter, harsh, and smooth ratings significantly associated with appeal in both genders, but these associations were larger in females compared to males. Data from the current report reinforces the need for researchers to study gender stratified effects in tobacco regulatory science.

Factors Associated With Prolonged Antibiotic Use in the Setting of Suspected Pneumonia and Negative Bronchoalveolar Lavage Cultures.

Background: Diagnostic criterion for pneumonia includes clinical data and bronchoalveolar lavage cultures (BALCx) to identify pathogens. Although ~60% of BALCx are negative, there may be reluctance to discontinue antibiotics, leading to prolonged antibiotic use (PAU). Objective: The purpose of this study is to compare outcomes of subjects with negative BALCx with PAU versus without prolonged antibiotic use (nPAU). Methods: A retrospective cohort study was conducted including subjects admitted to the intensive care unit (ICU), with suspected pneumonia, and negative BALCx. Data were compared based on length of exposure to antibiotics, PAU (antibiotics >4 days) versus nPAU (antibiotics <4 days). Results: A total of 128 subjects were included, 57 in the PAU group and 71 in the nPAU group. Baseline demographics were similar between groups. Severity of illness measured by multiple organ dysfunction scores at time of bronchoalveolar lavage (BAL) collection to final result showed a statistically significant decrease in the PAU group but not in the nPAU group. No differences were found in ICU days, ventilator-free days, or mortality; however, length of stay was longer for PAU (23 vs. 17, p = .04). In the PAU group, there were fewer BALCx results of "no growth" (23% vs. 45%, p = .04), more positive gram stains (83% vs. 60%, p = .01) and more positive non-BALCx (40% vs. 14%, p = .01). In a multivariate analysis, factors associated with PAU were positive BAL gram stains (adjusted odds ratio [aOR] 3.1, p = .037) and positive non-BALCx (aOR 4.7, p = .002). Conclusion: For subjects with suspected pneumonia and negative BALCx, positive non-BALCx and positive BALCx gram stain influenced the length of exposure of antibiotics.

Resolution of organ dysfunction as a predictor of long-term survival in necrotizing soft tissue infections: Analysis of the AB103 Clinical Composite Endpoint Study in Necrotizing Soft Tissue Infections trial and a retrospective claims database-linked chart study.

BACKGROUND: Necrotizing soft tissue infections (NSTIs) are an acute surgical condition with high morbidity and mortality. Timely identification, resuscitation, and aggressive surgical management have significantly decreased inpatient mortality. However, reduced inpatient mortality has shifted the burden of disease to long-term mortality associated with persistent organ dysfunction. METHODS: We performed a combined analysis of NSTI patients from the AB103 Clinical Composite Endpoint Study in Necrotizing Soft Tissue Infections randomized-controlled interventional trial (ATB-202) and comprehensive administrative database (ATB-204) to determine the association of persistent organ dysfunction on inpatient and long-term outcomes. Persistent organ dysfunction was defined as a modified Sequential Organ Failure Assessment (mSOFA) score of 2 or greater at Day 14 (D14) after NSTI diagnosis, and resolution of organ dysfunction defined as mSOFA score of 1 or less. RESULTS: The analysis included 506 hospitalized NSTI patients requiring surgical debridement, including 247 from ATB-202, and 259 from ATB-204. In both study cohorts, age and comorbidity burden were higher in the D14 mSOFA ≥2 group. Patients with D14 mSOFA score of 1 or less had significantly lower 90-day mortality than those with mSOFA score of 2 or higher in both ATB-202 (2.4% vs. 21.5%; p < 0.001) and ATB-204 (6% vs. 16%: p = 0.008) studies. In addition, in an adjusted covariate analysis of the combined study data sets D14 mSOFA score of 1 or lesss was an independent predictor of lower 90-day mortality (odds ratio, 0.26; 95% confidence interval, 0.13-0.53; p = 0.001). In both studies, D14 mSOFA score of 1 or less was associated with more favorable discharge status and decreased resource utilization. CONCLUSION: For patients with NSTI undergoing surgical management, persistent organ dysfunction at 14 days, strongly predicts higher resource utilization, poor discharge disposition, and higher long-term mortality. Promoting the resolution of acute organ dysfunction after NSTI should be considered as a target for investigational therapies to improve long-term outcomes after NSTI. LEVEL OF EVIDENCE: Prognostic/epidemiology study, level III.

Coarse-grained simulation of PEGylated and tethered protein devices at all experimentally accessible surface residues on ß-lactamase for stability analysis and comparison.

PEGylated and surface-tethered proteins are used in a variety of biotechnological applications, but traditional methods offer little control over the placement of the functionalization sites on the protein. Fortunately, recent experimental methods functionalize the protein at any location on the amino acid sequence, so the question becomes one of selecting the site that will result in the best protein function. This work shows how molecular simulation can be used to screen potential attachment sites for surface tethering or PEGylation. Previous simulation work has shown promise in this regard for a model protein, but these studies are limited to screening only a few of the surface-accessible sites or only considered surface tethering or PEGylation separately rather than their combined effects. This work is done to overcome these limitations by screening all surface-accessible functionalization sites on a protein of industrial and therapeutic importance (TEM-1) and to evaluate the effects of tethering and PEGylation simultaneously in an effort to create a more accurate screen. The results show that functionalization site effectiveness appears to be a function of super-secondary and tertiary structures rather than the primary structure, as is often currently assumed. Moreover, sites in the middle of secondary structure elements, and not only those in loops regions, are shown to be good options for functionalization-a fact not appreciated in current practice. Taken as a whole, the results show how rigorous molecular simulation can be done to identify candidate amino acids for functionalization on a protein to facilitate the rational design of protein devices.

Readmission After Emergency General Surgery: NSQIP Review of Risk, Cause and Ideal Follow-Up.

BACKGROUND: The Emergency General Surgery (EGS) population is particularly at high risk for readmission. Currently, no system exists to predict which EGS patients are most at risk. We hypothesized that a subset of EGS patients could be identified with increased 30-day unplanned readmission. We also hypothesized that a majority of readmissions occur sooner than the conventional 2-week follow-up period. METHODS: National Surgical Quality Improvement Program (NSQIP) nonelective general surgery patients were analyzed. Multivariable logistic regression identified factors with increased odds of unplanned readmission. AAST EGS Diagnosis Categories were used to categorize postop ICD-9 codes, and the top 10 CPT codes in each group were analyzed. Readmission rate, the reason for unplanned readmission, and time to readmission were analyzed. RESULTS: A total of 383,726 patients were identified with a readmission rate of 8.1% within 30 d of their primary procedure. The top 50 CPT codes accounted for 84% of EGS readmissions. Increased readmission risk was demonstrated for underweight patients (OR = 1.15, P < 0.05). High-risk hospital characteristics were LOS >2 d, any inpatient pulmonary complications, and discharge to any facility or rehab (all P < 0.05). Surgical site infections cause nearly 25% of readmissions. Intestinal procedures are most frequently readmitted (22% of EGS readmissions), with colorectal procedures having the higher odds of readmission. Most readmissions occur <10 d after discharge. CONCLUSIONS: A high-risk subpopulation exists within EGS, and most readmissions occur sooner than a typical 2-week follow-up. Early interventions for high-risk EGS subpopulations may allow for early intervention and reduction of unnecessary healthcare utilization.

Estimating the Impact of Necrotizing Soft Tissue Infections in the United States: Incidence and Re-Admissions.

Background: Previous estimates of the incidence of necrotizing soft tissue infections (NSTI) in the United States have substantial limitations and underestimate its occurrence. Improvements in hospital mortality after NSTI have increased the number of survivors at risk for long-term sequelae. This study estimates the incidence of NSTI and the burden of re-admission and associated healthcare spending in patients who survived admission for NSTI. Methods: Index admissions for NSTI were identified using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes combined with either Current Procedural Technology (CPT) or diagnosis-related group codes to increase specificity. Two separate datasets were used to provide primary and secondary estimates of the annual incidence of NSTIs in the United States: the National Inpatient Sample (NIS) for the years 2012-2016 and the Watson Health dataset for 2009-2013, respectively, and extrapolated to estimate the incidence for 2018. The Nationwide Readmissions Database (NRD) from 2013-2015 was used to estimate of the risk for re-admission, cost of re-admissions, and to compare 90-day re-admission rates for NSTI to common medical conditions. Results: National Inpatient Sample and Watson Health datasets demonstrated an increasing annual incidence and estimated 33,600 and 28,500 cases in 2018, respectively. The estimated annual incidences in the United States in 2018 were 10.3 and 8.7 per 100,000 persons, respectively. Risk of 90-day re-admission ranged from 24%-29% over the 3 years, 89% of which were unplanned. Of those re-admitted, 90% had one or more comorbidities, the most common diagnoses associated with re-admission were infection in 65%, acute kidney injury in 22%, and shock in 10%. The median re-admission length of stay was seven days (interquartile range [IQR]: 4-13 days) with a median cost of re-admission of $13,590 (IQR: $7186-$27440). Conclusion: The incidence of NSTI is more common than generally reported. Re-admission within 90 days is common, occurring in more than one in four survivors resulting in high healthcare costs.

Antibiotic Exposure Is Not Associated With Clearance of Bronchoalveolar Growth: Results From a Prospective Ventilator-Associated Pneumonia Study.

BACKGROUND: Ventilator-associated pneumonia is poorly understood in trauma. Ventilated trauma patients can develop bacterial burden without symptoms; the factors that influence this are unknown. METHODS: Injured adults ventilated for > 2 days were enrolled. Mini-bronchoalveolar lavage was performed for 14 days or until extubation. Semi-quantitative cultures were blinded from clinicians. All cultures with > 104 colony forming units (CFU) were assessed for antibiotic exposure (ABXE) and spectrum of coverage. mBAL CFU was assessed daily. RESULTS: 60 patients were ventilated for 9 days (median). There were 75 with > 104 CFU. 46 had > 104 CFU and no ABXE on the sample day. 74% had clearance or a decrease (CoD) in CFU without ABXE. 29 had > 104 CFU and ABXE on the sample day. 19 had ABXE with pathogen coverage. 84% had CoD in CFU. 10 had ABXE with no spectrum of coverage. 1/10 had increased CFU and the remaining 9/10 CoD in CFU. The three groups were not statistically different on chi-squared analysis. CONCLUSION: Clearance of pathogens on surveillance cultures was unaffected by ABXE.