Progress toward a vaccine for extraintestinal pathogenic E. coli (ExPEC) II: efficacy of a toxin-autotransporter dual antigen approach.

Extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of worldwide morbidity and mortality, the top cause of antimicrobial-resistant (AMR) infections, and the most frequent cause of life-threatening sepsis and urinary tract infections (UTI) in adults. The development of an effective and universal vaccine is complicated by this pathogen's pan-genome, its ability to mix and match virulence factors and AMR genes via horizontal gene transfer, an inability to decipher commensal from pathogens, and its intimate association and co-evolution with mammals. Using a pan virulome analysis of >20,000 sequenced E. coli strains, we identified the secreted cytolysin α-hemolysin (HlyA) as a high priority target for vaccine exploration studies. We demonstrate that a catalytically inactive pure form of HlyA, expressed in an autologous host using its own secretion system, is highly immunogenic in a murine host, protects against several forms of ExPEC infection (including lethal bacteremia), and significantly lowers bacterial burdens in multiple organ systems. Interestingly, the combination of a previously reported autotransporter (SinH) with HlyA was notably effective, inducing near complete protection against lethal challenge, including commonly used infection strains ST73 (CFT073) and ST95 (UTI89), as well as a mixture of 10 of the most highly virulent sequence types and strains from our clinical collection. Both HlyA and HlyA-SinH combinations also afforded some protection against UTI89 colonization in a murine UTI model. These findings suggest recombinant, inactive hemolysin and/or its combination with SinH warrant investigation in the development of an E. coli vaccine against invasive disease.

A New Model of Global Reconstructive Surgery Training With Reduced Carbon Footprint of Outreach.

This economic evaluation compares carbon dioxide emissions from air transportation for surgical mission trips vs team training trips.

Modeling the Lifetime Impact of Reconstructive Plastic Surgery Training: Implications for Building Capacity in Global Surgery.

Background: Training local surgeons and building local surgical capacity is critical to closing the gap in unmet surgical burden in low- and middle-income country (LMIC) settings. We propose a conceptual framework to quantify the impact of a single surgeon's training across multiple generations of trainees. Methods: A literature review was conducted to identify existing models for quantifying the impact of training. A model to estimate the attributable impact of surgical training was devised, based on a surgeon's attributable impact on a trainee and the lifetime number of cases trainees would perform. A quantitative survey was sent to high-income country and LMIC-based surgeons to determine the model's inputs across eight index procedures in reconstructive plastic surgery. Results: We found no existing models for quantifying the multigenerational impact of training in surgery, medicine, or nonmedical fields. Twenty-eight US-based academic plastic surgeons and 19 LMIC-based surgeons representing 10 countries provided responses. The lifetime impact of multigenerational surgical training ranged from 4100 attributable cases (skin graft) to 51,900 attributable cases (cleft lip repair) in high-income countries and from 18,200 attributable cases (carpal tunnel release) to 134,300 attributable cases (cleft lip repair) in LMICs. Conclusions: There is a sizeable impact in the first generation of training, and this impact is even greater in the second generation of training, highlighting the importance of a "multiplier effect," particularly in LMIC settings. Given the paucity of surgeons, this multiplier effect is critical in closing the surgical gap, as efforts are underway to train new cohorts of reconstructive plastic surgeons.

The Development and Validation of Data Elements and Process Steps for an Electronic Health Record for Hand Surgery Outreach Trips.

Background The surgical burden in low- and middle-income countries (LMICs) as reported by the number of surgical cases per capita is great. To improve global health and help address this burden, there has been a rise in surgical outreach to LMICs. In high-income countries, an electronic health record (EHR) is used to document and communicate data critical to the quality of care and patient safety. Despite this, there is little guidance or precedence on the data elements or processes for utilizing an EHR on outreach trips. We validated data elements and process steps for utilizing an EHR for hand surgery outreach trips. Methods We conducted a literature review to identify data elements collected during surgical outreach trips. A future-state process map for the collection and documentation of data elements within an EHR was developed through literature review and semistructured interviews with experts in global outreach. An expert consortium completed a modified RAND/University of California at Los Angeles Delphi process to evaluate the importance and feasibility of each data element and process step. Results In total, 65 data elements (e.g., date of birth) and 24 process steps (e.g., surgical site marking) were validated for use in an EHR for hand surgery outreach trips to LMICs. Conclusion This validated portfolio of data elements/process steps can serve as the foundation for pilot testing of an EHR to document and communicate critical patient data on hand surgery outreach trips. Utilization of an EHR during outreach trips to LMICs may serve to improve the safety and quality of care provided. The validated data elements/process steps can serve as a guide for EHR development and implementation of other surgical specialties.

Assessment of a Synergistic Effect of Platelet-Rich Plasma and Stem Cell-Seeded Hydrogel for Healing of Rat Chronic Rotator Cuff Injuries.

Outcomes after repair of chronic rotator cuff injuries remain suboptimal. Type-1 collagen-rich tendon hydrogel was previously reported to improve healing in a rat chronic rotator cuff injury model. Stem cell seeding of the tendon hydrogel improved bone quality in the same model. This study aimed to examine whether there was a synergistic and dose-dependent effect of platelet-rich plasma (PRP) on tendon-bone interface healing by combining PRP with stem cell-seeded tendon hydrogel. Human cadaveric tendons were processed into a hydrogel. PRP was prepared at two different platelet concentrations: an initial concentration (initial PRP group) and a higher concentration (concentrated PRP group). Tendon hydrogel was mixed with adipose-derived stem cells and one of the platelet concentrations. Methylcellulose, as opposed to saline, was used as a negative control due to comparable viscosity. The supraspinatus tendon was detached bilaterally in 33 Sprague-Dawley rats (66 shoulders). Eight weeks later, each detached tendon was repaired, and a hydrogel mixture or control was injected at the repair site. Eight weeks after repair, shoulder samples were harvested and assigned for biomechanical testing (n = 42 shoulders) or a combination of bone morphological and histological assessment (n = 24 shoulders). Biomechanical testing showed significantly higher failure load and stiffness in the concentrated PRP group than in control. Yield load in the initial and concentrated PRP groups were significantly higher than that in the control. There were no statistically significant differences between the initial and concentrated PRP groups. The addition of the highly concentrated PRP to stem cells-seeded tendon hydrogel improved healing biomechanically after chronic rotator cuff injury in rats compared to control. However, synergistic and dose-dependent effects were not seen.

The effects of daptomycin on cell wall biosynthesis in Enterococcal faecalis.

Daptomycin is a cyclic lipodepsipeptide antibiotic reserved for the treatment of serious infections by multidrug-resistant Gram-positive pathogens. Its mode of action is considered to be multifaceted, encompassing the targeting and depolarization of bacterial cell membranes, alongside the inhibition of cell wall biosynthesis. To characterize the daptomycin mode of action, 15N cross-polarization at magic-angle spinning NMR measurements were performed on intact whole cells of Staphylococcus aureus grown in the presence of a sub-inhibitory concentration of daptomycin in a chemically defined media containing L-[ϵ-15N]Lys. Daptomycin-treated cells showed a reduction in the lysyl-ε-amide intensity that was consistent with cell wall thinning. However, the reduced lysyl-ε-amine intensity at 10 ppm indicated that the daptomycin-treated cells did not accumulate in Park's nucleotide, the cytoplasmic peptidoglycan (PG) precursor. Consequently, daptomycin did not inhibit the transglycosylation step of PG biosynthesis. To further elucidate the daptomycin mode of action, the PG composition of daptomycin-susceptible Enterococcus faecalis grown in the presence of daptomycin was analyzed using liquid chromatography-mass spectrometry. Sixty-nine muropeptide ions correspond to PG with varying degrees of modifications including crosslinking, acetylation, alanylation, and 1,6-anhydrous ring formation at MurNAc were quantified. Analysis showed that the cell walls of daptomycin-treated E. faecalis had a significant reduction in PG crosslinking which was accompanied by an increase in lytic transglycosylase activities and a decrease in PG-stem modifications by the carboxypeptidases. The changes in PG composition suggest that daptomycin inhibits cell wall biosynthesis by impeding the incorporation of nascent PG into the cell walls by transpeptidases and maturation by carboxypeptidases. As a result, the newly formed cell walls become highly susceptible to degradation by the autolysins, resulting in thinning of the cell wall.

Automatic Detection of Perilunate and Lunate Dislocations on Wrist Radiographs Using Deep Learning.

SUMMARY: Delayed or missed diagnosis of perilunate or lunate dislocations can lead to significant morbidity. Advances in computer vision provide an opportunity to improve diagnostic performance. In this study, a deep learning algorithm was utilized for detection of perilunate and lunate dislocations on lateral wrist radiographs. A total of 435 lateral wrist radiographs were labeled as normal or pathologic (perilunate or lunate dislocation). The lunate in each radiograph was segmented with a rectangular bounding box. Images were partitioned into training and test sets. Two neural networks, consisting of an object detector followed by an image classifier, were applied in series. First, the object detection module was used to localize the lunate. Next, the image classifier performed a binary classification for normal or pathologic. The accuracy, sensitivity, and specificity of the overall system were evaluated. A receiver operating characteristic (ROC) curve and the associated area under the curve (AUC) were used to demonstrate the overall performance of the computer vision algorithm. The lunate object detector was 97.0% accurate at identifying the lunate. Accuracy was 98.7% among the sub-group of normal wrist radiographs, and 91.3% among the sub-group of wrist radiographs with perilunate/lunate dislocations. The perilunate/lunate dislocation classifier had a sensitivity (recall) of 93.8%, specificity of 93.3%, and accuracy of 93.4%. The AUC was 0.986. We have developed a proof-of-concept computer vision system for diagnosis of perilunate/lunate dislocations on lateral wrist radiographs. This novel deep learning algorithm has potential to improve clinical sensitivity to ultimately prevent delayed or missed diagnosis of these injuries.

Tenolysis and Salvage Procedures.

Complications in flexor tendon repair are common and include tendon rupture, adhesion formation, and joint contracture. Risk factors include preexisting conditions, gross contamination, concurrent fracture, early unplanned loading of the repaired tendon, premature cessation of splinting, and aggressive early active range of motion protocols with insufficient repair strength. Rupture of a repaired tendon should be followed by early operative exploration, debridement, and revision with a four-core strand suture and nonbraided epitendinous suture. Wide-awake flexor tenolysis should be considered when adhesion formation results in the plateaued range of motion, and passive motion exceeds active motion. Two-staged reconstruction is recommended when injury results in excessive scaring, joint contracture, or an incompetent pulley apparatus.

Broad protective vaccination against systemic Escherichia coli with autotransporter antigens.

Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading cause of adult life-threatening sepsis and urinary tract infections (UTI). The emergence and spread of multidrug-resistant (MDR) ExPEC strains result in a considerable amount of treatment failure and hospitalization costs, and contribute to the spread of drug resistance amongst the human microbiome. Thus, an effective vaccine against ExPEC would reduce morbidity and mortality and possibly decrease carriage in healthy or diseased populations. A comparative genomic analysis demonstrated a gene encoding an invasin-like protein, termed sinH, annotated as an autotransporter protein, shows high prevalence in various invasive ExPEC phylogroups, especially those associated with systemic bacteremia and UTI. Here, we evaluated the protective efficacy and immunogenicity of a recombinant SinH-based vaccine consisting of either domain-3 or domains-1,2, and 3 of the putative extracellular region of surface-localized SinH. Immunization of a murine host with SinH-based antigens elicited significant protection against various strains of the pandemic ExPEC sequence type 131 (ST131) as well as multiple sequence types in two distinct models of infection (colonization and bacteremia). SinH immunization also provided significant protection against ExPEC colonization in the bladder in an acute UTI model. Immunized cohorts produced significantly higher levels of vaccine-specific serum IgG and urinary IgG and IgA, findings consistent with mucosal protection. Collectively, these results demonstrate that autotransporter antigens such as SinH may constitute promising ExPEC phylogroup-specific and sequence-type effective vaccine targets that reduce E. coli colonization and virulence.

State of the art review: The management of chronic vascular disorders in the hand and upper limb.

This review article summarizes the basic principles of vascular anatomy, physiology, diagnostic work-up and treatment for patients with nontraumatic upper extremity vascular disorders. Vascular disorders can be considered vasospastic or occlusive. The most commonly encountered vasospastic condition is Raynaud's Phenomenon secondary to scleroderma. While historically this has been managed medically with vasodilators, more advanced cases can benefit from surgical treatment to improve blood flow and minimize tissue loss, with compelling evidence that earlier surgical intervention can modify disease process and should be considered. Occlusive disease can present as aneurysm or thrombosis and often requires surgical treatment with resection of the occluded segment with or without vascular reconstruction. In advanced atherosclerotic disease or end stage ischemia, arterialization of the venous system can be considered to avoid more proximal amputations.

A Framework and Blueprint for Building Capacity in Global Orthopaedic Surgical Outreach.

BACKGROUND: Nongovernmental organizations (NGOs) from high-income countries provide surgical outreach for patients in low and middle-income countries (LMICs); however, these efforts lack a coordinated measurement of their ability to build capacity. While the World Health Organization and others recommend outreach trips that aim to build the capacity of the local health-care system, no guidance exists on how to accomplish this. The objective of this paper is to establish a framework and a blueprint to guide the operations of NGOs that provide outreach to build orthopaedic surgical capacity in LMICs. METHODS: We conducted a qualitative analysis of semistructured interviews with 16 orthopaedic surgeons and administrators located in 7 countries (6 LMICs) on the necessary domains for capacity-building; the analysis was guided by a literature review of capacity-building frameworks. We subsequently conducted a modified nominal group technique with a consortium of 10 U.S.-based surgeons with expertise in global surgical outreach, which was member-checked with 8 new stakeholders from 4 LMICs. RESULTS: A framework with 7 domains for capacity-building in global surgical outreach was identified. The domains included professional development, finance, partnerships, governance, community impact, culture, and coordination. These domains were tiered in a hierarchical system to stratify the level of capacity for each domain. A blueprint was developed to guide the operations of an organization seeking to build capacity. CONCLUSIONS: The developed framework identified 7 domains to address when building capacity during global orthopaedic surgical outreach. The framework and its tiered system can be used to assess capacity and guide capacity-building efforts in LMICs. The developed blueprint can inform the operations of NGOs toward activities that focus on building capacity in order to ensure a measured and sustained impact.

Traceable and Integrated Pesticide Screening (TIPS), a Systematic and Retrospective Strategy for Screening 900 Pesticides and Unknown Metabolites in Tea.

Pesticide management is a crucial issue for sustainable agriculture and food safety. The high-resolution mass spectrometry (HRMS)-based screening method has become a popular choice to monitor pesticide residues in foods and the environment. Data-independent acquisition (DIA) was the first option allowing for this type of analysis due to the wide compound coverage compared to traditional targeted analysis using triple-quadrupole tandem mass spectrometry (QqQ). However, a higher false-positive detection rate is a critical shortcoming in DIA. To overcome this concern, a rigorous method is needed to determine the reliable information acquired from DIA screening. A systematic strategy, traceable and integrated pesticide screening (TIPS), was proposed in this study to comprehensively monitor pesticides and metabolites in a complex tea matrix, avoiding false-positive detection. A total of 900 pesticides were added to an in-house database and evaluated through precision tests, which showed good repeatability and reproducibility. One hundred pesticides and metabolites were detected and confirmed by TIPS in 98 commercial tea samples. In addition to the authorized pesticides that could be detected in TIPS, chlorfluazuron, diafenthiuron, and tolfenpyrad, which are pesticides not allowed to be used in tea farming, were frequently found in this study. In addition, dinotefuran DN and fenbuconazole metabolites RH-9129 and/or RH-9130 were tentatively identified in the archived data using retrospective analysis. The HRMS-based data in TIPS could be a record platform for tracing novel or emerging contaminants not initially targeted in samples. TIPS, a novel strategy, has great potential for rapidly conducting a risk assessment of unexpected pesticides in food.

Biomechanical, Histologic, and Micro-Computed Tomography Characterization of Partial-Width Full-Thickness Supraspinatus Tendon Injury in Rats.

PURPOSE: Partial rotator cuff tears can cause shoulder pain and dysfunction and are more common than complete tears. However, few studies examine partial injuries in small animals and, therefore a robust, clinically relevant model may be lacking. This study aimed to fully characterize the established rat model of partial rotator cuff injury over time and determine if it models human partial rotator cuff tears. METHODS: We created a full-thickness, partial-width injury at the supraspinatus tendon-bone interface bilaterally in 31 Sprague-Dawley rats. Rats were euthanized immediately, and at 2-, 3-, 4-, and 8-weeks after surgery. Fourteen intact shoulders were used as controls. Samples were assessed biomechanically, histologically, and morphologically. RESULTS: Biomechanically, load to failure in controls and 8 weeks after injury was significantly greater than immediately and 3 weeks after injury. Load to failure at 8 weeks was comparable to control. However, the locations of failure were different between intact shoulders and partially injured samples. Bone mineral density at 8 weeks was significantly greater than that at 2 and 3 weeks. Although no animals demonstrated propagation to complete tear and the injury site remodeled histologically, the appearance at 8 weeks was not identical to that in the controls. CONCLUSIONS: The biomechanical properties and bone quality decreased after the injury and was restored gradually over time with full restoration by 8 weeks after injury. However, the findings were not equivalent to the intact shoulder. This study demonstrated the limitations of the current model in its application to long-term outcome studies, and the need for better models that can be used to assess chronic partial rotator cuff injuries. CLINICAL RELEVANCE: There is no small animal model that mimics human chronic partial rotator cuff tears, which limits our ability to improve care for this common condition.

Anterior tibial artery pseudoaneurysm after ankle arthroscopy and Brostrom procedure treated with thrombin injection.

Ankle arthroscopy and the Brostrom procedure are common interventions for ankle instability, but they do carry a risk of vascular injury resulting in a pseudoaneurysm. We present a rare case of anterior tibial artery pseudoaneurysm after ankle arthroscopy and Brostrom procedure treated with direct thrombin injection. A 40-year-old male patient presented with progressive left anterior ankle pain and swelling 5 months after a left ankle arthroscopy and Brostrom procedure. MRI and ultrasound imaging was consistent with anterior tibial artery pseudoaneurysm. He was referred to interventional radiology for treatment. His pseudoaneurysm was successfully treated with an ultrasound guided direct thrombin injection. Several potential treatments are available for treatment of pseudoaneurysms. This includes surgical intervention, endovascular treatment, external compression, and direct thrombin injection. All of these treatment options have been explored in literature. Of these possible treatments, direct thrombin injection has the best combination of efficacy, complication rate, and recurrence rate, which makes it the preferred treatment for a pseudoaneurysm.

Humoral and cellular immune memory to four COVID-19 vaccines.

Multiple COVID-19 vaccines, representing diverse vaccine platforms, successfully protect against symptomatic COVID-19 cases and deaths. Head-to-head comparisons of T cell, B cell, and antibody responses to diverse vaccines in humans are likely to be informative for understanding protective immunity against COVID-19, with particular interest in immune memory. Here, SARS-CoV-2-spike-specific immune responses to Moderna mRNA-1273, Pfizer/BioNTech BNT162b2, Janssen Ad26.COV2.S, and Novavax NVX-CoV2373 were examined longitudinally for 6 months 100% of individuals made memory CD4+ T cells, with cTfh and CD4-CTL highly represented after mRNA or NVX-CoV2373 vaccination. mRNA vaccines and Ad26.COV2.S induced comparable CD8+ T cell frequencies, though only detectable in 60-67% of subjects at 6 months. A differentiating feature of Ad26.COV2.S immunization was a high frequency of CXCR3+ memory B cells. mRNA vaccinees had substantial declines in antibodies, while memory T and B cells were comparatively stable. These results may also be relevant for insights against other pathogens.

Humoral and cellular immune memory to four COVID-19 vaccines.

Multiple COVID-19 vaccines, representing diverse vaccine platforms, successfully protect against symptomatic COVID-19 cases and deaths. Head-to-head comparisons of T cell, B cell, and antibody responses to diverse vaccines in humans are likely to be informative for understanding protective immunity against COVID-19, with particular interest in immune memory. Here, SARS-CoV-2-spike-specific immune responses to Moderna mRNA-1273, Pfizer/BioNTech BNT162b2, Janssen Ad26.COV2.S and Novavax NVX-CoV2373 were examined longitudinally for 6 months. 100% of individuals made memory CD4 + T cells, with cTfh and CD4-CTL highly represented after mRNA or NVX-CoV2373 vaccination. mRNA vaccines and Ad26.COV2.S induced comparable CD8 + T cell frequencies, though memory CD8 + T cells were only detectable in 60-67% of subjects at 6 months. Ad26.COV2.S was not the strongest immunogen by any measurement, though the Ad26.COV2.S T cell, B cell, and antibody responses were relatively stable over 6 months. A differentiating feature of Ad26.COV2.S immunization was a high frequency of CXCR3 + memory B cells. mRNA vaccinees had substantial declines in neutralizing antibodies, while memory T cells and B cells were comparatively stable over 6 months. These results of these detailed immunological evaluations may also be relevant for vaccine design insights against other pathogens.

Kidney donor profile index and post-transplant health care utilization: Implications for value of transplant care delivery.

BACKGROUND: Centers discard high kidney donor profile index (KDPI) allografts, potentially related to delayed graft function and prolonged hospital use by kidney transplant recipients (KTR). We sought to determine whether high KDPI KTRs have excess health care utilization. METHODS: We conducted a retrospective cohort study from a high-volume center analyzing KTRs from January 3, 2011 to April 12, 2015 (n = 652). We measured differences in hospital use, emergency visits, and outpatient visits within the first 90 days between low (≤85%) versus high KDPI (>85%) KTRs, as well as long-term graft function and patient survival. RESULTS: High (n = 107) and low KDPI (n = 545) KTRs had similar length of stay (median = 3 days, P = .66), and readmission rates at 7, 30, and 90 days after surgery (all, P > .05). High KDPI kidneys were not associated with excess utilization of the hospital, emergency services, outpatient transplant clinics, or ambulatory infusion visits on univariate or multivariate analysis (all, P > .05). Low KDPI KTRs had significantly better eGFR at 2 years (Low vs. High KDPI: 60.35 vs. 41.54 ml/min, P < .001), but similar 3-year patient and graft survival (both, P > .09). CONCLUSIONS: High and low KDPI KTRs demonstrated similar 90-day risk-adjusted health care utilization, which should encourage use of high KDPI kidneys.