Molecular Machines that Facilitate Bacterial Outer Membrane Protein Biogenesis.

Almost all outer membrane proteins (OMPs) in Gram-negative bacteria contain a ß-barrel domain that spans the outer membrane (OM). To reach the OM, OMPs must be translocated across the inner membrane by the Sec machinery, transported across the crowded periplasmic space through the assistance of molecular chaperones, and finally assembled (folded and inserted into the OM) by the ß-barrel assembly machine. In this review, we discuss how considerable new insights into the contributions of these factors to OMP biogenesis have emerged in recent years through the development of novel experimental, computational, and predictive methods. In addition, we describe recent evidence that molecular machines that were thought to function independently might interact to form dynamic intermembrane supercomplexes. Finally, we discuss new results that suggest that OMPs are inserted primarily near the middle of the cell and packed into supramolecular structures (OMP islands) that are distributed throughout the OM.

Cryo-EM structures reveal multiple stages of bacterial outer membrane protein folding.

Transmembrane ß barrel proteins are folded into the outer membrane (OM) of Gram-negative bacteria by the ß barrel assembly machinery (BAM) via a poorly understood process that occurs without known external energy sources. Here, we used single-particle cryo-EM to visualize the folding dynamics of a model ß barrel protein (EspP) by BAM. We found that BAM binds the highly conserved "ß signal" motif of EspP to correctly orient ß strands in the OM during folding. We also found that the folding of EspP proceeds via "hybrid-barrel" intermediates in which membrane integrated ß sheets are attached to the essential BAM subunit, BamA. The structures show an unprecedented deflection of the membrane surrounding the EspP intermediates and suggest that ß sheets progressively fold toward BamA to form a ß barrel. Along with in vivo experiments that tracked ß barrel folding while the OM tension was modified, our results support a model in which BAM harnesses OM elasticity to accelerate ß barrel folding.

BamA forms a translocation channel for polypeptide export across the bacterial outer membrane.

The ß-barrel assembly machine (BAM) integrates ß-barrel proteins into the outer membrane (OM) of Gram-negative bacteria. An essential BAM subunit (BamA) catalyzes integration by promoting the formation of a hybrid-barrel intermediate state between its own ß-barrel domain and that of its client proteins. Here we show that in addition to catalyzing the integration of ß-barrel proteins, BamA functions as a polypeptide export channel. In vivo structural mapping via intermolecular disulfide crosslinking showed that the extracellular "passenger" domain of a member of the "autotransporter" superfamily of virulence factors traverses the OM through the BamA ß-barrel lumen. Furthermore, we demonstrate that a highly conserved residue within autotransporter ß-barrels is required to position the passenger inside BamA to initiate translocation and that during translocation, the passenger stabilizes the hybrid-barrel state. Our results not only establish a new function for BamA but also unify the divergent functions of BamA and other "Omp85" superfamily transporters.

Function of the Omp85 Superfamily of Outer Membrane Protein Assembly Factors and Polypeptide Transporters.

The Omp85 protein superfamily is found in the outer membrane (OM) of all gram-negative bacteria and eukaryotic organelles of bacterial origin. Members of the family catalyze both the membrane insertion of ß-barrel proteins and the translocation of proteins across the OM. Although the mechanism(s) by which these proteins function is unclear, striking new insights have emerged from recent biochemical and structural studies. In this review we discuss the entire Omp85 superfamily but focus on the function of the best-studied member, BamA, which is an essential and highly conserved component of the bacterial barrel assembly machinery (BAM). Because BamA has multiple functions that overlap with those of other Omp85 proteins, it is likely the prototypical member of the Omp85 superfamily. Furthermore, BamA has become a protein of great interest because of the recent discovery of small-molecule inhibitors that potentially represent an important new class of antibiotics.

Listeria monocytogenes Illness and Deaths Associated With Ongoing Contamination of a Multiregional Brand of Ice Cream Products, United States, 2010-2015.

BACKGROUND: Frozen foods have rarely been linked to Listeria monocytogenes illness. We describe an outbreak investigation prompted by both hospital clustering of illnesses and product testing. METHODS: We identified outbreak-associated listeriosis cases using whole-genome sequencing (WGS), product testing results, and epidemiologic linkage to cases in the same Kansas hospital. We reviewed hospital medical and dietary records, product invoices, and molecular subtyping results. Federal and state officials tested product and environmental samples for L. monocytogenes. RESULTS: Kansas officials were investigating 5 cases of listeriosis at a single hospital when, simultaneously, unrelated sampling for a study in South Carolina identified L. monocytogenes in Company A ice cream products made in Texas. Isolates from 4 patients and Company A products were closely related by WGS, and the 4 patients with known exposures had consumed milkshakes made with Company A ice cream while hospitalized. Further testing identified L. monocytogenes in ice cream produced in a second Company A production facility in Oklahoma; these isolates were closely related by WGS to those from 5 patients in 3 other states. These 10 illnesses, involving 3 deaths, occurred from 2010 through 2015. Company A ultimately recalled all products. CONCLUSIONS: In this US outbreak of listeriosis linked to a widely distributed brand of ice cream, WGS and product sampling helped link cases spanning 5 years to 2 production facilities, indicating longstanding contamination. Comprehensive sanitation controls and environmental and product testing for L. monocytogenes with regulatory oversight should be implemented for ice cream production.

Multistate outbreak of Salmonella Mbandaka infections linked to sweetened puffed wheat cereal - United States, 2018.

In May of 2018, PulseNet, the national molecular subtyping network for enteric pathogens, detected a multistate cluster of illnesses caused by an uncommon molecular subtype of Salmonella serovar Mbandaka. A case was defined as an illness in a person infected with the outbreak strain of Salmonella Mbandaka with illness onset on or after 3 March 2018 and before 1 September 2018. One-hundred thirty-six cases from 36 states were identified; 35 hospitalisations and no deaths were reported. Ill people ranged in age from <1 year to 95 years (median: 57 years). When standardised questionnaires did not generate a strong hypothesis, opened-ended interviews were performed. Sixty-three of 84 (75%) ultimately reported consuming or possibly consuming a specific sweetened puffed wheat cereal in the week before illness onset. Environmental sampling performed at the cereal manufacturing facility yielded the outbreak strain. The outbreak strain was also isolated from open cereal samples from ill people's homes and from a sealed retail sample. Due to these findings, the brand owner of the product issued a voluntary recall of the cereal on 14 June 2018. Additional investigation of the manufacturing facility identified persistent environmental contamination with Salmonella Mbandaka that was closely genetically related to other isolates in the outbreak. This investigation highlights the ability of Salmonella to survive in low-moisture environments, and the potential for prolonged outbreaks linked to products with long shelf lives and large distribution areas.

Addressing Transverse Plane Instability in the Modified Lapidus Arthrodesis: A Comparative Study of Screw Versus Suture and Button Fixation Device Technique.

The Lapidus arthrodesis is a powerful procedure for the correction of hallux valgus with metatarsus primus varus. Yet, first ray instability may persist despite correction of the primary deformity with 2 crossed screw fixation. A third screw is often utilized as the additional point of fixation for noteworthy residual transverse plane motion, but it is not without potential complications. The suture and button fixation device may be an appropriate alternative to the third screw construct. This retrospective cohort study identified clinical / radiographic outcomes and complication rates following a third point of fixation with either a screw or suture and button fixation device in patients undergoing a modified Lapidus arthrodesis. One surgeon performed all of the Lapidus procedure with a third screw while the other surgeon performed all with a suture and button fixation device. Of 136 consecutive patients who underwent a modified Lapidus arthrodesis, 83 (61%) patients required a third point of fixation for satisfactory stabilization of the first ray. Surgical technique was similar between the 2 surgeons; however, one utilized the suture and button fixation device method (n = 36), while the other used a third screw for fixation (n = 47). Many of the clinical outcomes, radiographic results, and the union rate were similar between the 2 methods. Nineteen (40%) complications occurred in the third screw group compared to 6 (17%) in the suture and button fixation device group. However, the third screw group demonstrated 100% maintenance of deformity correction at 1 year versus 95% in the suture and button fixation device group. Although fixation with a suture and button fixation device was associated with fewer complications, a larger study is necessary to determine if these variations are statistically significant.

Calibration of an Electrical Analog Model of Liver Hemodynamics in Fontan Patients.

Fontan associated liver disease is a common complication in patients with Fontan circulation, who were born with a single functioning heart ventricle. The hepatic venous pressure gradient (HVPG) is used to assess liver health and is a surrogate measure of the pressure gradient across the entire liver (portal pressure gradient (PPG)). However, it is thought to be inaccurate in Fontan patients. The main objectives of this study were (1) to apply an existing detailed lumped parameter model (LPM) of the liver to Fontan patients using patient-specific clinical data and (2) to determine whether HVPG is a suitable measurement of PPGs in these patients. An existing LPM of the liver blood circulation was applied and tuned to simulate patient-specific liver hemodynamics. Geometries were collected from seven adult Fontan patients and used to evaluate model parameters. The model was solved and tuned using waveform measurements of flows, inlet and outlet pressures. The predicted ratio of portal to hepatic venous pressures is comparable to in vivo measurements. The results confirmed that HVPG is not suitable for Fontan patients, as it would underestimate the portal pressures gradient by a factor of 3 to 4. Our patient-specific liver model provides an estimate of the pressure drop across the liver, which differs from the clinically used metric HVPG. This work represents a first step toward models suitable to assess liver health in Fontan patients and improve its long-term management.

Competition warm-up strategies in sub-elite and elite flat-water sprint kayak athletes.

This study compared warm-up strategies employed by sub-elite and world-class elite sprint kayak athletes, evaluating their impact on subsequent race performance. Forty-seven (n = 33 male, n = 14 female) athletes competing at a National Sprint Kayak Championships had Global Navigation Satellite System devices fitted to their kayak to measure speed, distance and stroke rate during the on-water warm-up before racing (OWWU), and during racing. The OWWU total duration, average/peak speeds and stroke rates, and the time spent in speed-zones classified based upon athletes' relative race-pace (low-to-moderate, moderate-to-high, and race-specific) were compared between events, sexes, and athlete standard. The relationship of these variables to subsequent race performance, expressed as a percentage of the best time-to-completion for each event (%racebest), was also examined. Women spent greater OWWU time at moderate-to-high and race-specific speeds compared to men prior to 200-m and 500-m races (P ≤.001). Sub-elite men reported greater total OWWU duration for 200-m and 500-m (P ≤.025), but not for 1000-m races (P >.05) compared to elite men. Finally, %racebest had large inverse correlations to OWWU peak speed for men's 200-m (r = -.53), and average stroke rate for women's 500-m races (r = -.50). This study provides valuable insight for competition warm-up routines based upon data from an elite athlete population.

Interoperability and Considerations for Standards-Based Exchange of Medical Images: HIMSS-SIIM Collaborative White Paper.

This white paper explores the considerations of standards-based interoperability of medical images between organizations, patients, and providers. In this paper, we will look at three different standards-based image exchange implementations that have been deployed to facilitate exchange of images between provider organizations. The paper will describe how each implementation uses applicable technology and standards; the image types that are included; and the governance policies that define participation, access, and trust. Limitations of the solution or non-standard approaches to solve challenges will also be identified. Much can be learned from successes elsewhere, and those learnings will point to recommendations of best practices to facilitate the adoption of image exchange.

The Correlation of the Trans-Atlantic Inter-Society Consensus Classification to Outcomes of Pedal Amputations.

In an attempt at limb salvage for patients with peripheral arterial disease, revascularization is often performed prior to pedal amputation. The purpose of this study was to evaluate the association between proximal arterial lesions, based on Trans-Atlantic Inter-Society Consensus aortoiliac, femoropopliteal, and infrapopliteal classifications, and healing pedal amputations post endovascular revascularization. Patients with revascularization up to 90 days prior to pedal amputation with a minimum of 12 months postoperative follow-up were included. Each level of proximal disease was subdivided into Trans-Atlantic Inter-Society Consensus classifications A through D, which range in severity from a single short stenosis or occlusion to more complex stenoses and chronic total occlusion. For comparison, we categorized A and/or B lesions into Group 1 and C and/or D lesions into Group 2. The frequency of proximal lesions was recorded as either isolated, bi-level, or multilevel disease. Chi-square and Fisher's exact tests were used to compare categorical variables. Of the 310 patients, there were a total of 68 aortoiliac, 256 femoropopliteal, and 172 infrapopliteal lesions; 140 patients had isolated lesions, 154 had bi-level disease, and 16 had multilevel disease. Although not statistically significant, patients in Group 1 (A and/or B lesions) had higher proportion of failed amputation compared to Group 2 (C and/or D lesions) in either aortoiliac (84.4% vs 15.6%, p = .17), femoropopliteal (61.2% vs 38.8%, p = .72), or infrapopliteal (57.3% vs 42.7%, p = .44). Bi-level disease showed a higher proportion of failure (50.6%) compared to isolated lesions (43.8%) and multilevel disease (5.6%), (p = .86). To our knowledge, this is the first study to evaluate the association between Trans-Atlantic Inter-Society Consensus arterial lesions and incisional healing of pedal amputations. Despite our belief, there was no correlation between patients with simple, isolated lesions compared to either complex arterial lesions or multilevel disease in healing pedal amputations.

The Effects of Endovascular Timing and In-line Flow on the Success of Pedal Amputations.

There has been a growing trend toward endovascular intervention to improve peripheral flow in patients with peripheral arterial disease. To date, there is no clear consensus regarding timing of lower-extremity amputations after revascularization. The purpose of this study was to evaluate the effects of timing between endovascular intervention and minor lower-extremity amputations and its influence on wound healing and limb loss within 1 year. A secondary purpose was to evaluate the impact of restoring in-line flow on healing rates. A total of 310 patients who underwent endovascular intervention and a minor lower-extremity amputation within 90 days were included in the study. Healing rates were defined as optimal, delayed, or failure. There was a statistically significant difference between patients with optimal healing to delayed healing and amputation ≥30 days after endovascular intervention (p = .037). We found no difference in healing rates in regard to amputation timing when examining patients who ultimately healed versus patients who failed to heal (p = .6717). Absence of in-line flow (p = .0177), male sex (p = .0090) and diabetes mellitus (p = .0076) were statistically significant factors for failing to heal. Presence of infection (p ≤ .0001) and wound dehiscence (p ≤ .001) were also associated with a failure to heal. End-stage renal disease trended toward significance for failing to heal (p = .065). Amputation-free survival at 1 year after endovascular intervention and pedal amputation was 76.8% (n = 238). Our findings suggest that in the absence of infection, performing minor lower-extremity amputations 15 to 60 days after endovascular intervention may allow for improved healing. Absence of in-line flow, male sex, diabetes mellitus, postoperative infection, and wound dehiscence are significant factors for failure.

Microorganisms Associated With Osteomyelitis of the Foot and Ankle.

Osteomyelitis of the foot and ankle is a challenge to treat and creates a significant demand on both the patient and the healthcare system. The purposes of this study were to determine the microorganisms associated with foot and ankle osteomyelitis, to evaluate the change in methicillin-resistant Staphylococcus aureus (MRSA) between 2005 and 2010, and to determine the relationship between these infecting organisms and patient comorbidities. The medical records for 302 patients diagnosed with osteomyelitis of the foot and ankle, 151 in 2005 and 151 in 2010, were randomly selected and evaluated. The authors reviewed the demographics, comorbidities, microorganism(s) confirmed with bone biopsy and culture, location, and use of antibiotics before bone biopsy. Gram-positive bacteria were the most prevalent, composing 81.9% of the isolates in 2005 and 59.6% in 2010. Methicillin-sensitive Staphylococcus aureus was the most common in both cohorts. Conversely, the incidence of MRSA statistically decreased from 28.3% to 10.6% from 2005 to 2010 (p < .0001). Gram-negative bacteria were found in 39.5% of the 2005 isolates and 31.8% of those from 2010. Pseudomonas sp. was the most common gram-negative bacteria. Patients with peripheral vascular disease had a significantly higher incidence of gram-negative bacteria (odds ratio 2.1, 95% confidence interval, 1.3 to 3.6, p = .003). The results of this study reveal that MSSA was the most common bacteria, incidence of MRSA decreased between the 2005 to 2010, and patients with peripheral vascular disease have a significantly higher incidence of gram-negative bacteria.

Early Protected Weightbearing After Open Reduction Internal Fixation of Ankle Fractures With Trans-syndesmotic Screws.

Traditional postoperative care after open reduction internal fixation (ORIF) of unstable ankle fractures with syndesmotic instability includes non-weightbearing for 6 to 8 weeks. However, prolonged non-weightbearing may be detrimental. The goal of this case series was to assess the outcomes of early protected weightbearing after operative treatment of acute ankle fractures with syndesmotic instability requiring screw stabilization. Fifty-eight consecutive patients, treated from January 2006 to January 2013, met the inclusion criteria with a minimum follow up of 1 year. Electronic medical records and radiographs were reviewed for patient and surgical characteristics, postoperative complications, and maintenance of reduction. Patients initiated walking at an average of 10 days (range 1 to 15) postoperatively. Surgical treatment consisted of operative reduction with standard fixation devices and 1 or 2 trans-syndesmotic screws that purchased 4 cortices. All 58 patients maintained correction after surgery when allowed to weightbear early in the postoperative recovery. Five complications (8.6%) occurred in the 58 patients, which included 3 superficial infections (5.2%) and 2 cases (3.4%) of neuritis. The maintenance of reduction and low complication rate in this study support the option of early protected weightbearing after ankle fracture ORIF with trans-syndesmotic fixation.

Impact of fenestrated stent graft misalignment on patient outcomes.

OBJECTIVE: During fenestrated endovascular aneurysm repair (FEVAR), accurate alignment of the fenestration and the target artery is necessary to prevent complications. This study's objective is to determine the incidence of clinical outcomes following fenestration misalignment during FEVAR. METHODS: A single-center, retrospective chart review was performed for all elective FEVARs between January 2008 and April 2015. Data were gathered from patient records and intraoperative imaging. Native vessel angles were calculated using the vessel centerlines. Intraoperative stent graft orientation was determined by changing the angle of the image intensifier as the fenestration was profiled for cannulation. Vertical fenestration misalignment was defined as 4 mm or greater and is the distance from the center of the fenestration markers to the center of the target vessel ostium at the time of cannulation. Horizontal stent graft misalignment was defined as a difference between the native vessel angle and the intraoperative fenestration angle of 15° or more. Early and late clinical outcomes were analyzed with respect to the presence of either vertical or horizontal misalignment of the renal artery fenestrations. RESULTS: The study cohort includes 65 patients who underwent FEVAR during this study period. A horizontal misalignment of 15° or more occurred in 40% of patients (n = 26) and 30° or more in 9.2% of patients (n = 6). A vertical misalignment of 4 mm or greater occurred in 32.3% of patients (n = 21). The incidence of severe postoperative complications, defined as any in-hospital end-organ ischemia and/or death, was significantly greater for patients with stent graft misalignment-31% (n = 11) vs 3% (n = 1) in the aligned group. There was a trend toward higher rates of target vessel cannulation failure in patients with stent graft misalignment 3% (n = 99 fenestrations) vs 0% (n = 76 fenestrations). The combined incidence of any intraoperative target vessel complication was significantly higher in patients with misalignment, 8.1% (4, 15) vs 1.3% (0, 8). Long-term survival was significantly lower in patients with stent graft misalignment, which was primarily driven by high intraoperative and in-hospital mortality rates (P < .05). CONCLUSIONS: Intraoperative stent graft misalignment is associated with higher rates of procedural target vessel complications and severe postoperative adverse events. Patients with stent graft misalignment should be considered at high risk for early postoperative complications. These results highlight an important need for improved FEVAR planning.

Impact of Insertion Technique and Iliac Artery Anatomy on Fenestrated Endovascular Aneurysm Repair.

Purpose: To develop a mechanically realistic aortoiliac model to evaluate anatomic variables associated with stent-graft rotation and to assess common deployment techniques that may contribute to rotation. Materials and Methods: Idealized aortoiliac geometries were constructed either through direct 3-dimensional (3D) printing (rigid) or through casting with polyvinyl alcohol using 3D-printed molds (flexible). Flexible model bending rigidity was controlled by altering wall thickness. Three flexible patient-specific models were also created based on the preoperative computed tomography angiograms. Zenith infrarenal and fenestrated devices were used in this study. The models were pressurized to 100 mm Hg with normal saline. Deployments were performed under fluoroscopy at 37°C. Rotation was calculated by tracking the change in position of gold markers affixed to the devices. Results: In the rigid idealized models, stent-graft rotation increased with increasing torsion; torsion levels of 1.6, 2.6, and 3.6 mm-1 had mean rotations of 5.2°±0.03°, 11.2°±4.8°, and 27.6°±13.0°, respectively (p<0.001). In the flexible models, the highest rotation (58°±3.0°) was observed in models with high torsion and high rigidity (7.5 mm-1 net torsion and 254 N·m2 flexural rigidity). No rotation was observed in the absence of torsion. Applying torque to the device during insertion significantly increased stent-graft rotation by an average of 28° across all levels of torsion (p<0.01). Multiple device insertions prior to deployment did not change the observed device rotation. The patient-specific models accurately predicted the degree of rotation seen intraoperatively to within 5°. Conclusion: Insertion technique plays an important role in the degree of stent-graft rotation during deployment. Our model suggests that in vivo correction of device orientation can increase the observed rotation and supports the concept of fully removing the device, adjusting the orientation, and subsequently reinserting. Additionally, increasing iliac artery torsion in the presence of increased vessel rigidity results in stent-graft rotation.

Demographic Profile of Chiropractors Who Treat Children: A Multinational Survey.

OBJECTIVE: The purpose of this study was to survey the demographic profile and educational background of chiropractors with pediatric patients on a multinational scale. METHODS: A multinational online cross-sectional demographic survey conducted over a 15-day period in July 2010. The survey was electronically administered via chiropractic associations in 17 countries, using SurveyMonkey for data acquisition, transfer, and descriptive analysis. RESULTS: The response rate was 10.1%, and 1498 responses were received from 17 countries on 6 continents. Of these, 90.4% accepted pediatric cases. The average practitioner was male (61.1%) and 41.4 years old, had 13.6 years in practice, and saw 107 patient visits per week. Regarding educational background, 63.4% had a bachelor's degree or higher in addition to their chiropractic qualification, and 18.4% had a postgraduate certificate or higher in pediatric chiropractic. CONCLUSION: This is the first study about chiropractors who treat children from the United Arab Emirates, Peru, Japan, South Africa, and Spain. Although the response rate was low, the results of this multinational survey suggest that pediatric chiropractic care may be a common component of usual chiropractic practice on a multinational level for these respondents.

Prediction of advanced endovascular stent graft rotation and its associated morbidity and mortality.

OBJECTIVE: Advanced endovascular aneurysm repair (EVAR) with fenestrated and branched stent grafts is increasingly being used to repair complex aortic aneurysms; however, these devices can rotate unpredictably during deployment, leading to device misalignment. The objectives of this study were to quantify the short-term clinical outcomes in patients with intraoperative stent graft rotation and to identify quantitative anatomic markers of the arterial geometry that can predict stent graft rotation preoperatively. METHODS: A prospective study evaluating all patients undergoing advanced EVAR was conducted at two university-affiliated hospitals between November 2015 and December 2016. Stent graft rotation (defined as ≥10 degrees) was measured on intraoperative fluoroscopic video of the deployment sequence. Standard preoperative computed tomography angiography imaging was used to calculate the geometric properties of the arterial anatomy. Any in-hospital and 30-day complications were prospectively documented, and a composite outcome of any end-organ ischemia or death was used as the primary end point. RESULTS: Thirty-nine patients undergoing advanced EVAR were enrolled in the study with a mean age of 75 years (interquartile range [IQR], 71-80 years) and a mean aneurysm diameter of 64 mm (IQR, 59-65 mm). The incidence of stent graft rotation was 37% (n = 14), with a mean rotation of 25 degrees (IQR, 21-28 degrees). A nominal logistic regression model identified iliac artery torsion, volume of iliac artery calcification, and stent graft length as the primary predictive factors. The total net torsion and the total volume of calcific plaque were higher in patients with stent graft rotation, 8.9 ± 0.8 mm-1 vs 4.1 ± 0.5 mm-1 (P < .0001) and 1054 ± 144 mm3 vs 525 ± 83 mm3 (P < .01), respectively. The length of the implanted stent grafts was also higher in patients with intraoperative rotation, 172 ± 9 mm vs 156 ± 8 mm (P < .01). The composite outcome of any end-organ ischemia or death was also substantially higher in patients with stent graft rotation (36% vs 0%; P = .004). In addition, patients with stent graft rotation had significantly higher combined rates of type Ib and type III endoleaks (43% vs 8%; P = .03). CONCLUSIONS: Patients with intraoperative stent graft rotation have a significantly higher rate of severe postoperative complications, and this is strongly associated with higher levels of iliac artery torsion, calcification, and stent graft length. These findings suggest that preoperative quantitative analysis of iliac artery torsion and calcification may improve risk stratification of patients before advanced EVAR.

Predicting Rotation in Fenestrated Endovascular Aneurysm Repair Using Finite Element Analysis.

Fenestrated endovascular aneurysm repair (FEVAR) is a minimally invasive method of abdominal aortic aneurysm (AAA) repair utilized in patients with complex vessel anatomies. Stent grafts (SG) used in this process contain fenestrations within the device that need to be aligned with the visceral arteries upon successful SG deployment. Proper alignment is crucial to maintain blood flow to these arteries and avoid surgical complications. During fenestrated SG deployment, rotation of the SG can occur during the unsheathing process. This leads to misalignment of the vessels, and the fenestrations and is associated with poor clinical outcomes. The aim of this study was to develop a computational model of the FEVAR process to predict SG rotation. Six patient-specific cases are presented and compared with surgical case data. Realistic material properties, frictional effects, deployment methods, and boundary conditions are included in the model. A mean simulation error of 2 deg (range 1-4 deg) was observed. This model was then used to conduct a parameter study of frictional properties to see if rotation could be minimized. This study showed that increasing or decreasing the coefficients of friction (COF) between the sheath and the vessel walls would decrease the amount of rotation observed. Our model accurately predicts the amount of SG rotation observed during FEVAR and can be used as a preoperative planning tool within the surgical workflow.

Singleton Sequence Type 382, an Emerging Clonal Group of Listeria monocytogenes Associated with Three Multistate Outbreaks Linked to Contaminated Stone Fruit, Caramel Apples, and Leafy Green Salad.

Three multistate outbreaks between 2014 and 2016, involving case patients in and outside the United States, were linked to stone fruit, caramel apples, and packaged leafy green salad contaminated with Listeria monocytogenes singleton sequence type 382 (ST382), a serotype IVb-v1 clone with limited genomic divergence. Isolates from these outbreaks and other ST382 isolates not associated with these outbreaks were analyzed by whole-genome sequencing (WGS) analysis. The primary differences among ST382 strains were single nucleotide polymorphisms (SNPs). WGS analysis differentiated ST382 from a clonal complex 1 outbreak strain co-contaminating the caramel apples. WGS clustered food, environmental, and clinical isolates within each outbreak, and also differentiated among the three outbreak strains and epidemiologically unrelated ST382 isolates, which were indistinguishable by pulsed-field gel electrophoresis. ST382 appeared to be an emerging clone that began to diverge from its ancestor approximately 32 years before 2016. We estimated that there was 1.29 nucleotide substitution per genome (2.94 Mbp) per year for this clone.