Mapping of oxidative modifications on the alpha-keto glutarate dehydrogenase complex induced by singlet oxygen: effects on structure and activity.

The large multi-subunit mitochondrial alpha-keto glutarate dehydrogenase (KGDH) complex plays a key, rate-determining, role in the tricarboxylic acid (Krebs) cycle, catalyzing the conversion of alpha-keto glutarate to succinyl-CoA. This complex is both a source and target of oxidants, but the sites of modification and association with structural changes and activity loss are poorly understood. We report here oxidative modifications induced by Rose Bengal (RB) in the presence of O2, a source of singlet oxygen (1O2). A rapid loss of activity was detected, with this being dependent on light exposure, illumination time, and the presence of RB and O2. Activity loss was enhanced by D2O (consistent with 1O2 involvement), but diminished by both pre- and (to a lesser extent) post-illumination addition of lipoic acid and lipoamide. Aggregates containing all three KGDH subunits were detected on photooxidation. LC-MS experiments provided evidence for oxidation at 45 sites, including specific Met, His, Trp, Tyr residues and the lipoyllysine active-site cofactor. Products include mono- and di-oxygenated species, and kynurenine from Trp. Mapping of the modifications to the 3-D structure showed that these are localized to both the inner channel and the external surface, consistent with reactions of free 1O2, however the sites and extent of modification do not correlate with their solvent accessibility. These products are generated concurrently with loss of activity, indicative of strong links between these events. These data provide evidence for the impairment of KGDH activity by 1O2 via the oxidation of specific residues on the protein subunits of the complex.

Complete genomes of two cluster AK Arthrobacter phages isolated from soil samples in Newburgh, NY, United States.

Two phages belonging to Arthrobacter phage cluster AK were isolated from soil samples collected in Newburgh, NY in 2021. Both are lytic with a genome organization typical of siphoviruses except for two genes encoding minor tail proteins with pyocin-knob domains found early in the genome, before the terminase gene.

Can optical evaluation distinguish between t1a and t1b esophageal adenocarcinoma: an international expert inter-observer agreement study.

INTRODUCTION: While piecemeal endoscopic mucosal resection (EMR) for T1a oesophageal adenocarcinoma is acceptable, enbloc-R0 excision is advocated for T1b disease as it may offer a potential cure and mitigate recurrence. Thus, distinguishing between T1a and T1b disease is imperative under current treatment paradigms. We sought to ascertain whether expert Barrett's endoscopists were able to make this distinction based on optical evaluation. METHODS: Sixty sets of endoscopic images of histologically confirmed high grade dysplasia (HGD), T1a and T1b disease (n=20 for each) were compiled from consecutive patients at a single institution. Each set contained four images, and were standardized to include an overview, a close-up in high-definition white light, a near-focus magnification image, and a narrow-band image. Experts were invited to predict histology for each set. RESULTS: 19 experts from 8 countries (Australia, USA, Italy, Netherlands, Germany, Canada, Belgium, and Portugal) participated. The majority had been practicing for >20 years, with a median annual case volume for Barrett's EMR of 50 (IQR 18-75), and Barrett's ESD of 25 (IQR 10-45). Oesophageal adenocarcinoma (T1a/b) could be distinguished from HGD, with a pooled sensitivity of 89.1% (95% CI:84.7-93.4. When predicting T-stage for T1b adenocarcinoma cases, pooled sensitivity was 43.8% (95% CI:29.9-57.7). Fleiss' kappa was 0.421 (95% CI:0.399-0.442, P<0.001), indicating fair-to-moderate agreement. CONCLUSIONS: Expert Barrett's endoscopists can reliably differentiate T1a/T1b oesophageal adenocarcinoma from HGD. Although there is fair-to-moderate agreement for T-staging, T1b disease cannot be reliably distinguished from T1a disease. This may have implications on clinical decision making and selection of endoscopic treatment methods.

Disease heterogeneity and molecular classification of inflammatory palmoplantar diseases.

BACKGROUND: Palmoplantar pustulosis (PPP) is an inflammatory disease characterized by relapsing eruptions of neutrophil-filled, sterile pustules on the palms and soles that can be clinically difficult to differentiate from non-pustular palmoplantar psoriasis (palmPP) and dyshidrotic palmoplantar eczema (DPE). OBJECTIVE: We sought to identify overlapping and unique PPP, palmPP, and DPE drivers to provide molecular insight into their pathogenesis. METHODS: We performed bulk RNA sequencing of lesional PPP (n = 33), palmPP (n = 5), and DPE (n = 28) samples, as well as 5 healthy nonacral and 10 healthy acral skin samples. RESULTS: Acral skin showed a unique immune environment, likely contributing to a unique niche for palmoplantar inflammatory diseases. Compared to healthy acral skin, PPP, palmPP, and DPE displayed a broad overlapping transcriptomic signature characterized by shared upregulation of proinflammatory cytokines (TNF, IL-36), chemokines, and T-cell-associated genes, along with unique disease features of each disease state, including enriched neutrophil processes in PPP and to a lesser extent in palmPP, and lipid antigen processing in DPE. Strikingly, unsupervised clustering and trajectory analyses demonstrated divergent inflammatory profiles within the 3 disease states. These identified putative key upstream immunologic switches, including eicosanoids, interferon responses, and neutrophil degranulation, contributing to disease heterogeneity. CONCLUSION: A molecular overlap exists between different inflammatory palmoplantar diseases that supersedes clinical and histologic assessment. This highlights the heterogeneity within each condition, suggesting limitations of current disease classification and the need to move toward a molecular classification of inflammatory acral diseases.

Therapeutic monoclonal antibodies in allergy: Targeting IgE, cytokine, and alarmin pathways.

The etiology of allergy is closely linked to type 2 inflammatory responses ultimately leading to the production of allergen-specific immunoglobulin E (IgE), a key driver of many allergic conditions. At a high level, initial allergen exposure disrupts epithelial integrity, triggering local inflammation via alarmins including IL-25, IL-33, and TSLP, which activate type 2 innate lymphoid cells as well as other immune cells to secrete type 2 cytokines IL-4, IL-5 and IL-13, promoting Th2 cell development and eosinophil recruitment. Th2 cell dependent B cell activation promotes the production of allergen-specific IgE, which stably binds to basophils and mast cells. Rapid degranulation of these cells upon allergen re-exposure leads to allergic symptoms. Recent advances in our understanding of the molecular and cellular mechanisms underlying allergic pathophysiology have significantly shaped the development of therapeutic intervention strategies. In this review, we highlight key therapeutic targets within the allergic cascade with a particular focus on past, current and future treatment approaches using monoclonal antibodies. Specific targeting of alarmins, type 2 cytokines and IgE has shown varying degrees of clinical benefit in different allergic indications including asthma, chronic spontaneous urticaria, atopic dermatitis, chronic rhinosinusitis with nasal polyps, food allergies and eosinophilic esophagitis. While multiple therapeutic antibodies have been approved for clinical use, scientists are still working on ways to improve on current treatment approaches. Here, we provide context to understand therapeutic targeting strategies and their limitations, discussing both knowledge gaps and promising future directions to enhancing clinical efficacy in allergic disease management.

Preinjection With Ligation-Assisted Endoscopic Mucosal Resection for Barrett's Dysplasia and Early Esophageal Adenocarcinoma: Characteristic Histological Features of the Depth of Resection.

BACKGROUND AND AIM: Endoscopic mucosal resection (EMR) is an established technique for the diagnosis and treatment of high-grade dysplasia (HGD) and early esophageal adenocarcinoma (EAC) in Barrett's esophagus. Submucosal preinjection is not universally used or generally recommended when performing routine ligation-assisted EMR. Prior studies, however, have demonstrated evidence of at least superficial muscle injury on ligation-assisted EMR without submucosal injection. There are limited published data supporting any potential benefit of submucosal preinjection. Our aim was to review this technique and determine the rate of any degree of muscle injury in patients with Barrett's HGD and EAC treated with submucosal preinjection before ligation-assisted EMR. METHODS: Patients undergoing submucosal preinjection before ligation-assisted EMR for Barrett's esophagus at a single institution between 2012 and 2016 were identified. Data were collected regarding patient demographics and medical history, endoscopy and histopathology findings, adverse events, and subsequent outcomes. All EMR specimens were reviewed by an expert gastrointestinal pathologist. RESULTS: One hundred fifty consecutive EMR procedures were performed on 70 patients. Of 70 patients, 85.7% of patients were men, with a median age of 68 years. EAC was identified in 75 specimens (50%) and HGD in 44 specimens (29.3%). Deep resection margins were clear of adenocarcinoma in all specimens. Muscularis propria was not identified in any of the 150 specimens. There were no cases of post-EMR perforation. CONCLUSIONS: Preinjection before ligation-assisted EMR achieved complete excision with histologically clear margins, without histological evidence of any inadvertent muscularis propria.

iGATE analysis improves the interpretability of single-cell immune landscape of influenza infection.

Influenza poses a persistent health burden worldwide. To design equitable vaccines effective across all demographics, it is essential to better understand how host factors such as genetic background and aging affect the single-cell immune landscape of influenza infection. Cytometry by time-of-flight (CyTOF) represents a promising technique in this pursuit, but interpreting its large, high-dimensional data remains difficult. We have developed a new analytical approach, in silico gating annotating training elucidating (iGATE), based on probabilistic support vector machine classification. By rapidly and accurately "gating" tens of millions of cells in silico into user-defined types, iGATE enabled us to track 25 canonical immune cell types in mouse lung over the course of influenza infection. Applying iGATE to study effects of host genetic background, we show that the lower survival of C57BL/6 mice compared with BALB/c was associated with a more rapid accumulation of inflammatory cell types and decreased IL-10 expression. Furthermore, we demonstrate that the most prominent effect of aging is a defective T cell response, reducing survival of aged mice. Finally, iGATE reveals that the 25 canonical immune cell types exhibited differential influenza infection susceptibility and replication permissiveness in vivo, but neither property varied with host genotype or aging. The software is available at https://github.com/UmichWenLab/iGATE.

Factorial validity and measurement invariance of the Athlete Burnout Questionnaire (ABQ).

The Athlete Burnout Questionnaire (ABQ) is the gold standard measure for burnout in athletes. However, previous assessments of factorial validity have: (a) tested overly restrictive measurement models; (b) provided mixed support for factorial validity; and (c) not been applied to assess measurement invariance across gender, sport type, or age. To address these issues, we used ABQ data provided by 914 athletes (Mage = 21.75 years, SD = 8.79) and examined factorial validity using confirmatory factor analysis (CFA) and exploratory structural equation modelling (ESEM) techniques. We also examined measurement invariance of the ABQ data across reported gender (female, male), sport type (individual, team), and age (≤18 years, >18 years) groups. The analyses revealed that an ESEM model provided superior fit over the corresponding CFA model. In terms of measurement invariance, support was provided for the equivalence of the ABQ across each group. This means that researchers using the ABQ can collect data across these groups and examine potential differences with confidence that the ABQ is approximately invariant. In all, we provide evidence that the majority of ABQ items are key target construct indicators and the burnout construct (as measured by the ABQ) has the same structure and meaning to different athlete groups.

Quantitative Foot Muscle Magnetic Resonance Imaging Reliably Measures Disease Progression in Children and Adolescents with Charcot-Marie-Tooth Disease Type 1A.

Quantitative muscle fat fraction (FF) responsiveness is lower in younger Charcot-Marie-Tooth disease type 1A (CMT1A) patients with lower baseline calf-level FF. We investigated the practicality, validity, and responsiveness of foot-level FF in this cohort involving 22 CMT1A patients and 14 controls. The mean baseline foot-level FF was 25.9 ± 20.3% in CMT1A patients, and the 365-day FF (n = 15) increased by 2.0 ± 2.4% (p < 0.001 vs controls). Intrinsic foot-level FF demonstrated large responsiveness (12-month standardized response mean (SRM) of 0.86) and correlated with the CMT examination score (ρ = 0.58, P = 0.01). Intrinsic foot-level FF has the potential to be used as a biomarker in future clinical trials involving younger CMT1A patients. ANN NEUROL 2024;96:170-174.

Elevated levels of iodide promote peroxidase-mediated protein iodination and inhibit protein chlorination.

At inflammatory sites, immune cells generate oxidants including H2O2. Myeloperoxidase (MPO), released by activated leukocytes employs H2O2 and halide/pseudohalides to form hypohalous acids that mediate pathogen killing. Hypochlorous acid (HOCl) is a major species formed. Excessive or misplaced HOCl formation damages host tissues with this linked to multiple inflammatory diseases. Previously (Redox Biology, 2020, 28, 101331) we reported that iodide (I⁻) modulates MPO-mediated protein damage by decreasing HOCl generation with concomitant hypoiodous acid (HOI) formation. HOI may however impact on protein structure, so in this study we examined whether and how HOI, from peroxidase/H2O2/I⁻ systems ± Cl⁻, modifies proteins. Experiments employed MPO and lactoperoxidase (LPO) and multiple proteins (serum albumins, anastellin), with both chemical (intact protein and peptide mass mapping, LC-MS) and structural (SDS-PAGE) changes assessed. LC-MS analyses revealed dose-dependent iodination of anastellin and albumins by LPO/H2O2 with increasing I⁻. Incubation of BSA with MPO/H2O2/Cl⁻ revealed modest chlorination (Tyr286, Tyr475, ∼4 %) and Met modification. Lower levels of these species, and extensive iodination at specific Tyr and His residues (>20 % modification with ≥10 µM I⁻) were detected with increasing I⁻. Anastellin dimerization was inhibited by increasing I⁻, but less marked changes were observed with albumins. These data confirm that I⁻ competes with Cl⁻ for MPO and is an efficient HOCl scavenger. These processes decrease protein chlorination and oxidation, but result in extensive iodination. This is consistent with published data on the presence of iodinated Tyr on neutrophil proteins. The biological implications of protein iodination relative to chlorination require further clarification.

A dual fluorescent herpes simplex virus type 1 recombinant reveals divergent outcomes of neuronal infection.

Critical stages of lytic herpes simplex virus type 1 (HSV-1) replication are marked by the sequential expression of immediate early (IE) to early (E), then late (L) viral genes. HSV-1 can also persist in neuronal cells via a non-replicative, transcriptionally repressed infection called latency. The regulation of lytic and latent transcriptional profiles is critical to HSV-1 pathogenesis and persistence. We sought a fluorescence-based approach to observe the outcome of neuronal HSV-1 infection at the single-cell level. To achieve this goal, we constructed and characterized a novel HSV-1 recombinant that enables discrimination between lytic and latent infection. The dual reporter HSV-1 encodes a human cytomegalovirus-immediate early (hCMV-IE) promoter-driven enhanced yellow fluorescent protein (eYFP) to visualize the establishment of infection and an endogenous mCherry-VP26 fusion to report lytic replication. We confirmed that viral gene expression, replication, and spread of infection are not altered by the incorporation of the fluorescent reporters, and fluorescent protein (FP) detection virtuously reports the progression of lytic replication. We demonstrate that the outcome of HSV-1 infection of compartmentalized primary neurons is determined by viral inoculating dose: high-dose axonal inoculation proceeds to lytic replication, whereas low-dose axonal inoculation establishes a latent HSV-1 infection. Interfering with low-dose axonal inoculation via small molecule drugs reports divergent phenotypes of eYFP and mCherry reporter detection, correlating with altered states of viral gene expression. We report that the transcriptional state of neuronal HSV-1 infection is variable in response to changes in the intracellular neuronal environment.IMPORTANCEHerpes simplex virus type 1 (HSV-1) is a prevalent human pathogen that infects approximately 67% of the global human population. HSV-1 invades the peripheral nervous system, where latent HSV-1 infection persists within the host for life. Immunological evasion, viral persistence, and herpetic pathologies are determined by the regulation of HSV-1 gene expression. Studying HSV-1 gene expression during neuronal infection is challenging but essential for the development of antiviral therapeutics and interventions. We used a recombinant HSV-1 to evaluate viral gene expression during infection of primary neurons. Manipulation of cell signaling pathways impacts the establishment and transcriptional state of HSV-1 latency in neurons. The work here provides critical insight into the cellular and viral factors contributing to the establishment of latent HSV-1 infection.

Comparison of Hounsfield Units within the Humeral Trochlea and Medial Coronoid Process in a Population of Labrador X Golden Retriever Guide Dogs and Border Collies.

OBJECTIVE: The aim of this study was to determine if variations in Hounsfield units (HU) are present within the elbow between asymptomatic dogs of two breeds of dogs susceptible to elbow dysplasia. STUDY DESIGN: Guide Dogs and Border Collies that presented for routine computed tomography (CT) screening for elbow dysplasia prior to breeding were evaluated. All dogs had no documented history of lameness. Dogs diagnosed with CT as being free of elbow dysplasia were included. The CT images were randomized and assessed by three blinded observers. A standardised approach to CT image reconstruction to create consistent image planes was used. Hounsfield units were measured within a standardised region of interest (ROI) at the humeral trochlea and medial coronoid process. The minimum, mean and maximum HU within each ROI was recorded. RESULTS: Eighty-six elbows were included in the study with 32 Guide Dogs, and 11 Border Collies. Guide Dogs had significantly higher minimum (99.75 HU, 95% confidence interval [CI]: 15.02-184.48, p = 0.022), mean (115.09 HU, 95% CI: 80.53-149.64, p < 0.01) and maximum (74.00 HU, 95% CI: 44.58-103.42, p < 0.01) difference in HU within the medial coronoid process ROI, and significantly higher mean (146.49 HU, 95% CI: 100.12-192.87, p < 0.01) and maximum (147.77 HU, 95% CI: 102.57-192.97, p < 0.01) difference in HU within the humeral trochlea ROI. CONCLUSION: In this dataset breed variations in elbow HU were present between asymptomatic Guide Dogs and Border Collies. This needs to be considered in breeding screening programmes to avoid over-interpretation of elbow sclerosis, in the absence of elbow pathology.

Microbiology of infection-related complications after transrectal ultrasound-guided prostate biopsy.

INTRODUCTION: The objective of this study was to describe the incidence, microbiology, and risk factors related to infectious complications after transrectal prostate biopsies. METHODS: This was a single-center, retrospective cohort study of patients undergoing prostate biopsies. Throughout the study period, the institutional recommendation for antibiotic prophylaxis was cephalexin and ciprofloxacin. Due to the desire to limit fluoroquinolone use, the ciprofloxacin duration of therapy was reduced from 48 to 24 hours in the middle of the study period. The primary outcome was the incidence of infection-related complications, defined as a urinary tract infection (UTI) or bacteremia within 30 days post-procedure. RESULTS: A total of 1471 transrectal prostate biopsies were included. All patients received antibiotic prophylaxis, with 86.1% (1268/1472) of patients receiving both ciprofloxacin and cephalexin. The incidence of infection-related complications was 1.6% (24/1471). Four patients experienced bacteremia, all of which were due to E. coli, and all of these patients had received antibiotic prophylaxis with an active antibiotic. The use of ciprofloxacin was associated with a lower risk of infection-related complications (odds ratio [OR ] 0.20, 95% confidence interval [CI] 0.07, 0.55). Bacteriuria within one year prior to the procedure was associated with increased risk of infection-related complications (OR 4.77, 95% CI 1.34, 16.93). Four (0.3%) patients experienced an antibiotic-related adverse event. CONCLUSIONS: We observed a low rate of infection-related complications and antibiotic-related adverse events in the setting of antibiotic prophylaxis with ciprofloxacin and cephalexin for 24 hours, without pre-procedure rectal culture screening. Investigation into procedural or host factors may uncover opportunities to further reduce infection-related complications.

Antigen-Clustered Nanovaccine Achieves Long-Term Tumor Remission by Promoting B/CD 4 T Cell Crosstalk.

Current cancer vaccines using T cell epitopes activate antitumor T cell immunity through dendritic cell/macrophage-mediated antigen presentation, but they lack the ability to promote B/CD4 T cell crosstalk, limiting their anticancer efficacy. We developed antigen-clustered nanovaccine (ACNVax) to achieve long-term tumor remission by promoting B/CD4 T cell crosstalk. The topographic features of ACNVax were achieved using an iron nanoparticle core attached with an optimal number of gold nanoparticles, where the clusters of HER2 B/CD4 T cell epitopes were conjugated on the gold surface with an optimal intercluster distance of 5-10 nm. ACNVax effectively trafficked to lymph nodes and cross-linked with BCR, which are essential for stimulating B cell antigen presentation-mediated B/CD4 T cell crosstalk in vitro and in vivo. ACNVax, combined with anti-PD-1, achieved long-term tumor remission (>200 days) with 80% complete response in mice with HER2+ breast cancer. ACNVax not only remodeled the tumor immune microenvironment but also induced a long-term immune memory, as evidenced by complete rejection of tumor rechallenge and a high level of antigen-specific memory B, CD4, and CD8 cells in mice (>200 days). This study provides a cancer vaccine design strategy, using B/CD4 T cell epitopes in an antigen clustered topography, to achieve long-term durable anticancer efficacy through promoting B/CD4 T cell crosstalk.

Construct validation of a novel synthetic tendon model used for assessing surgeon performance in a simulated core suture tendon repair technique.

BACKGROUND: The strength of tendon repair is dependent on the quality of the core suture. Organic and synthetic materials have been used to simulate tendon repair for training; however, no model has undergone construct validation. OBJECTIVES: To determine the construct validity of a novel synthetic tendon repair model. METHODS: Synthetic silicone tendon models were used to simulate adult Achilles tendon (AT) and digital flexor tendon (FT). Participants were categorised into novice, intermediate, and advanced groups based on prior surgical experience. Participants repaired tendons using the modified Kessler technique. A validated motion analysis system was used to measure the duration, path length, and movement count during the simulated task. A global rating score was also used to assess the performance. RESULTS: All participants in the novice (n = 12), intermediate (n = 8) and advanced (n = 11) groups completed the tasks. The results (mean±standard deviation) were duration (872 ± 335, 492 ± 257 and 357 ± 40 s), path length (9493 ± 3173, 6668 ± 1740 and 4672 ± 1228 cm), movement count (4974 ± 673, 4228 ± 259 and 3962 ± 69) and global rating (39 ± 13, 61 ± 14, 81 ± 5), respectively. The Kruskal-Wallis test was significant for all outcome measures (p < 0.01). Significant differences in duration and movement count were identified post-hoc in the AT model for each experience group (p < 0.05), and between novice and intermediate participants for FT repair (p < 0.04). Global rating was significantly different between all groups and was highly correlated with motion metrics (p < 0.01). CONCLUSION: The results support construct validity of this novel simulated tendon repair model. The global rating scores may allow wide utility of this simulation. This model provides a valid and safe environment for surgical trainees to practice tendon repair with several cost, ethical and logistical benefits over animal tendon use. 248/250.

Methylene Blue in a High-Performance Hydrogen-Organic Rechargeable Fuel Cell.

A hydrogen-organic hybrid flow battery (FB) has been developed using methylene blue (MB) in an aqueous acid electrolyte with a theoretical positive electrolyte energy storage capacity of 65.4 A h L-1. MB paired with the versatile H2/H+ redox couple at the negative electrode forms the H2-MB rechargeable fuel cell, with no loss in capacity (5 sig. figures) over 30 100% discharge cycles of galvanostatic cycling at 50 mA cm-2, which shows excellent stability. A peak power density of 238 mW cm-2 has also been demonstrated by utilizing 1.0 M MB electrolyte. This represents a type of scalable electrochemical energy storage system with favorable properties in terms of material cost, stability, crossover management, and energy and power density, overcoming many typical limitations of organic-based redox FBs.

Single-cell herpes simplex virus type 1 infection of neurons using drop-based microfluidics reveals heterogeneous replication kinetics.

Single-cell analyses of viral infections reveal heterogeneity that is not detected by traditional population-level studies. This study applies drop-based microfluidics to investigate the dynamics of herpes simplex virus type 1 (HSV-1) infection of neurons at the single-cell level. We used micrometer-scale Matrigel beads, termed microgels, to culture individual murine superior cervical ganglia (SCG) neurons or epithelial cells. Microgel-cultured cells are encapsulated in individual media-in-oil droplets with a dual-fluorescent reporter HSV-1, enabling real-time observation of viral gene expression and replication. Infection within drops revealed that the kinetics of initial viral gene expression and replication were dependent on the inoculating dose. Notably, increasing inoculating doses led to earlier onset of viral gene expression and more frequent productive viral replication. These observations provide crucial insights into the complexity of HSV-1 infection in neurons and emphasize the importance of studying single-cell outcomes of viral infection. These techniques for cell culture and infection in drops provide a foundation for future virology and neurobiology investigations.

Multi-species biofilms of environmental microbiota isolated from fruit packing facilities promoted tolerance of Listeria monocytogenes to benzalkonium chloride.

Listeria monocytogenes may survive and persist in food processing environments due to formation of complex multi-species biofilms of environmental microbiota that co-exists in these environments. This study aimed to determine the effect of selected environmental microbiota on biofilm formation and tolerance of L. monocytogenes to benzalkonium chloride in formed biofilms. The studied microbiota included bacterial families previously shown to co-occur with L. monocytogenes in tree fruit packing facilities, including Pseudomonadaceae, Xanthomonadaceae, Microbacteriaceae, and Flavobacteriaceae. Biofilm formation ability and the effect of formed biofilms on the tolerance of L. monocytogenes to benzalkonium chloride was measured in single- and multi-family assemblages. Biofilms were grown statically on polystyrene pegs submerged in a R2A broth. Biofilm formation was quantified using a crystal violet assay, spread-plating, confocal laser scanning microscopy, and its composition was assessed using amplicon sequencing. The concentration of L. monocytogenes in biofilms was determined using the most probable number method. Biofilms were exposed to the sanitizer benzalkonium chloride, and the death kinetics of L. monocytogenes were quantified using a most probable number method. A total of 8, 8, 6, and 3 strains of Pseudomonadaceae, Xanthomonadaceae, Microbacteriaceae, and Flavobacteriaceae, respectively, were isolated from the environmental microbiota of tree fruit packing facilities and were used in this study. Biofilms formed by Pseudomonadaceae, Xanthomonadaceae, and all multi-family assemblages had significantly higher concentration of bacteria, as well as L. monocytogenes, compared to biofilms formed by L. monocytogenes alone. Furthermore, multi-family assemblage biofilms increased the tolerance of L. monocytogenes to benzalkonium chloride compared to L. monocytogenes mono-species biofilms and planktonic multi-family assemblages. These findings suggest that L. monocytogenes control strategies should focus not only on assessing the efficacy of sanitizers against L. monocytogenes, but also against biofilm-forming microorganisms that reside in the food processing built environment, such as Pseudomonadaceae or Xanthomonadaceae.

When less is more: lower esophageal sphincter-preserving peroral endoscopic myotomy is effective for non-achalasia esophageal motility disorders.

BACKGROUND: Non-achalasia esophageal motility disorders (NAEMDs), encompassing distal esophageal spasm (DES) and hypercontractile esophagus (HCE), are rare conditions. Peroral endoscopic myotomy (POEM) is a promising treatment option. In NAEMDs, unlike with achalasia, the lower esophageal sphincter (LES) functions normally, suggesting the potential of LES preservation during POEM. METHODS: This retrospective two-center observational study focused on patients undergoing LES-preserving POEM (LES-POEM) for NAEMD. Eckardt scores were assessed pre-POEM and at 6, 12, and 24 months post-POEM, with follow-up endoscopy at 6 months to evaluate for reflux esophagitis. Clinical success, defined as an Eckardt score ≤3, served as the primary outcome. RESULTS: 227 patients were recruited over 84 months until May 2021. Of these, 16 underwent LES-POEM for an NAEMD (9 with HCE and 7 with DES). The median pre-POEM Eckardt score was 6.0 (interquartile range [IQR] 5.0-7.0), which decreased to 1.0 (IQR 0.0-1.8; P<0.001) 6 months post-POEM. This was sustained at 24 months, with an Eckardt score of 1.0 (IQR 0.0-1.8; P<0.001). Two patients (12.5%) developed Los Angeles grade A or B esophagitis. CONCLUSIONS: LES-POEM for NAEMD demonstrates favorable clinical outcomes, with infrequent esophagitis and reintervention for LES dysfunction rarely required.