VlsE, the nexus for antigenic variation of the Lyme disease spirochete, also mediates early bacterial attachment to the host microvasculature under shear force.

Hematogenous dissemination is a critical step in the evolution of local infection to systemic disease. The Lyme disease (LD) spirochete, which efficiently disseminates to multiple tissues, has provided a model for this process, in particular for the key early event of pathogen adhesion to the host vasculature. This occurs under shear force mediated by interactions between bacterial adhesins and mammalian cell-surface proteins or extracellular matrix (ECM). Using real-time intravital imaging of the Lyme spirochete in living mice, we previously identified BBK32 as the first LD spirochetal adhesin demonstrated to mediate early vascular adhesion in a living mouse; however, deletion of bbk32 resulted in loss of only about half of the early interactions, suggesting the existence of at least one other adhesin (adhesin-X) that promotes early vascular interactions. VlsE, a surface lipoprotein, was identified long ago by its capacity to undergo rapid antigenic variation, is upregulated in the mammalian host and required for persistent infection in immunocompetent mice. In immunodeficient mice, VlsE shares functional overlap with OspC, a multi-functional protein that displays dermatan sulfate-binding activity and is required for joint invasion and colonization. In this research, using biochemical and genetic approaches as well as intravital imaging, we have identified VlsE as adhesin-X; it is a dermatan sulfate (DS) adhesin that efficiently promotes transient adhesion to the microvasculature under shear force via its DS binding pocket. Intravenous inoculation of mice with a low-passage infectious B. burgdorferi strain lacking both bbk32 and vlsE almost completely eliminated transient microvascular interactions. Comparative analysis of binding parameters of VlsE, BBK32 and OspC provides a possible explanation why these three DS adhesins display different functionality in terms of their ability to promote early microvascular interactions.

Impact of mepolizumab in patients with high-burden severe asthma within a managed care population.

OBJECTIVE: To evaluate the real-world impact of mepolizumab on the incidence of asthma exacerbations, oral corticosteroid (OCS) use and asthma exacerbation-related costs in patients with high-burden severe asthma. METHODS: This was a retrospective study of the MarketScan Commercial and Medicare Databases in patients with high-burden severe asthma (≥80th percentile of total healthcare expenditure and/or significant comorbidity burden). Patients were ≥12 years of age upon mepolizumab initiation (index date November 1, 2015-December 31, 2018) and had ≥2 mepolizumab administrations during the 6 months post-index. Asthma exacerbation frequency (primary outcome), use of OCS (secondary outcome), and asthma exacerbation-related costs (exploratory outcome) were assessed during the 12 months pre-index (baseline) and post-index (follow-up). RESULTS: In total, 281 patients were analyzed. Mepolizumab significantly reduced the proportion of patients with any asthma exacerbation (P < 0.001) or exacerbations requiring hospitalization (P = 0.004) in the follow-up versus baseline period. The mean number of exacerbations decreased from 2.5 to 1.5 events/patient/year (relative reduction: 40.0%; P < 0.001). The proportion of patients with ≥1 OCS claim also decreased significantly from 94.0% to 81.9% (relative reduction: 12.9%; P < 0.001), corresponding to a decrease from 6.6 to 4.7 claims/person/year (P < 0.001). Of the 264 patients with ≥1 OCS claim during baseline, 191 (72.3%) showed a decrease in mean daily OCS use by ≥50% in 117 patients (61.3%). Total asthma exacerbation-related costs were significantly lower after mepolizumab was initiated (P < 0.001). CONCLUSIONS: Mepolizumab reduced exacerbation frequency, OCS use and asthma exacerbation-related costs in patients with high-cost severe asthma. Mepolizumab provides real-world benefits to patients, healthcare systems and payers.

A real-world study of inhaled corticosteroid use in patients with severe eosinophilic asthma treated with mepolizumab.

BACKGROUND: Mepolizumab is a humanized anti-interleukin-5, monoclonal antibody approved for the treatment of patients with severe eosinophilic asthma (SEA). There is limited evidence that mepolizumab can reduce inhaled corticosteroid (ICS) use in these patients. OBJECTIVE: To investigate changes in ICS use and clinical outcomes in patients with SEA who initiated mepolizumab treatment. METHODS: This retrospective cohort study (GlaxoSmithKline identification: 212695/HO-20-19951) used administrative claims data from the IBM Watson Health MarketScan Database (identification period: November 2015 to March 2018). Eligible patients had SEA and were receiving high-dose ICS and mepolizumab. Use of ICS, oral corticosteroid (OCS), and short-acting ß2-agonist and exacerbation frequency were analyzed quarterly during the 12-month follow-up period after mepolizumab initiation. RESULTS: In total, 351 patients were included. The proportion of patients using high-dose ICS decreased in quarters 1 to 4 after mepolizumab initiation (79.8%, 74.6%, 68.9%, 65.5%, respectively); 49.0% of patients reduced or discontinued ICS for one or more quarter. Comparing patients who discontinued ICS vs those who remained on high-dose ICS, a lower proportion had chronic OCS use (3.4%-9.2% vs 13.9%-16.8%) and OCS burst use (15.4%-20.8% vs 19.7%-26.1%) in quarters 1 to 4; similarly in quarters 3 and 4, a lower proportion of patients had exacerbations (16.9% and 20.3% vs 27.2% and 27.7%) and short-acting ß2-agonist claims (35.4% and 39.2% vs 43.3% and 49.0%, respectively). CONCLUSION: In patients with SEA on high-dose ICS, a reduction in both ICS and OCS use was observed after initiating mepolizumab. These findings have important implications for clinical outcomes and follow-up care in this patient population.

Factors leading to discontinuation of biologic therapy in patients with severe asthma.

OBJECTIVE: To assess patient- and physician-reported reasons for discontinuing biologic therapy among patients with severe asthma from a real-world US cohort. METHODS: This retrospective analysis surveyed US physicians and their patients with severe asthma who were receiving/had previously received biologic therapy between August and December 2019. Physicians managing ≥3 patients with asthma per month completed surveys on disease management, demographics, exacerbation history, and biologic adherence for eligible patients. Patients could voluntarily complete a questionnaire, providing perceptions of their disease and treatment. RESULTS: 117 physicians completed case reports for 285 patients; 85 patients had discontinued biologic therapy. Physicians (n = 85) and patients (n = 64) reported patient request (28.2% and 46.9%), shortness of breath (45.9% and 23.4%), other chronic respiratory symptoms (29.4% and 10.9%), cost/reimbursement (17.7%/9.4% and 20.3%/7.8%), and exacerbations (25.9% and 10.9%) among the main reasons for biologic discontinuation. Patients who continued biologic therapy were older (mean age 47.6 years) than those who discontinued (43.8 years), and were more likely to have ≥2 exacerbations in the previous year (52.5% vs 35.3%), allergic rhinitis (70.0% vs 62.4%), or chronic rhinosinusitis (30.0% vs 12.9%). Side effects were cited as reasons by only 15.3% and 7.8% of physicians and patients, respectively. CONCLUSIONS: The most common reasons given for discontinuation of biologic therapy were lack of symptom control, exacerbations, cost, and patient request. These data highlight the complexity of care for this patient group and the need for ongoing, regular assessment of common challenges to biologic continuation and reasons for discontinuation, including both clinical and non-clinical factors.

Real-world effectiveness of mepolizumab in patients with severe asthma and associated comorbidities.

BACKGROUND: Patients with severe asthma frequently have associated comorbidities, which can compound existing symptoms, complicating asthma management. OBJECTIVE: To describe the real-world effectiveness of mepolizumab in patients with severe asthma stratified by common overlapping comorbidities. METHODS: This was a retrospective analysis of patients with asthma from the MarketScan Commercial and Medicare Supplemental Database initiating mepolizumab treatment (index date). Eligible patients had more than or equal to 1 claim (excluding claims for diagnostic tests) with a diagnosis code for more than or equal to 1 of 7 comorbidities (atopic disease, nasal polyps, chronic sinusitis, obesity, respiratory infections, chronic obstructive pulmonary disease, and depression/anxiety) during the 12-month preindex baseline period; these were used to stratify patients into 7 nonmutually exclusive subgroups. Outcomes included asthma exacerbations and exacerbation-related health care resource utilization during the 12-month baseline and follow-up periods. Each patient acted as their own control. RESULTS: Of the 639 patients included, the most common comorbidities were atopic diseases (73.2%), respiratory infections (55.6%), and chronic sinusitis (45.1%). Across all 7 comorbidity subgroups, there were significant (P < .05) reductions of 38% to 55% and 57% to 83% in exacerbations and exacerbations requiring hospitalization, respectively, during the follow-up vs baseline period, except for exacerbations requiring hospitalization in the nasal polyp subgroup, owing to the small subgroup sample size. During the follow-up vs baseline periods, mean number of oral corticosteroids claims was significantly (P < .001) reduced by 29% to 38%; 39% to 47% of patients achieved greater than or equal to 50% oral corticosteroids dose reduction. Significant reductions in exacerbation-related health care resource utilization were also observed. CONCLUSION: Mepolizumab treatment provided real-world clinical benefits in patients.

Real-world evidence: Patient views on asthma in respiratory specialist clinics in America.

BACKGROUND: Approximately 30% to 50% of patients with moderate/severe asthma have inadequately controlled disease despite adherence to inhaled corticosteroid (ICS)/long-acting ß2-agonist (LABA) therapy. Data on prevalence and burden of uncontrolled asthma in specialty settings are lacking. OBJECTIVE: To evaluate the prevalence and burden of uncontrolled asthma in respiratory specialist clinics in the United States. METHODS: Adults with physician-diagnosed asthma attending pulmonary and allergy clinics with self-reported ICS use in the previous 4 weeks completed an electronic questionnaire including the Asthma Control Test and St George's Respiratory Questionnaire. Additional information was collected using an electronic case report form. RESULTS: Of 774 patients attending 12 pulmonary and 12 allergy clinics, 53% were not well controlled (mean [SD] Asthma Control Test, 14.3 [3.6] vs 22.4 [1.6] in well-controlled patients). Among ICS/LABA users, 56% were not well controlled, which increased with increasing ICS dose (low-dose 45.7%; high-dose 59.7%). The not well-controlled group reported more respiratory illnesses, more comorbidities, and poorer health-related quality of life (mean [SD] St George's Respiratory Questionnaire, 46.1 [18.9] vs 19.8 [12.9] in the well-controlled group). These patients also had more asthma exacerbations (≥1 exacerbation, 68.9% vs 43.1%) and increased health care resource utilization (≥1 asthma-related hospitalization, 10.7% vs 2.7%); 27.3% were also receiving systemic corticosteroids. Approximately 40% of the population were eligible for step-up to ICS/LABA/long-acting muscarinic antagonist triple therapy, and 20% were eligible for biologic therapy. CONCLUSION: Substantial unmet needs exist among patients with inadequately controlled asthma managed in United States specialist settings, which may be addressed by improved patient and physician education, better guideline implementation, and improved adherence.

Time-to-first exacerbation, adherence, and medical costs among US patients receiving umeclidinium/vilanterol or tiotropium as initial maintenance therapy for chronic obstructive pulmonary disease: a retrospective cohort study.

BACKGROUND: Adherence to chronic obstructive pulmonary disease (COPD) maintenance medication is important for managing symptoms and exacerbation risk, and is associated with reduced mortality, hospitalizations, and costs. This study compared on-treatment exacerbations, medical costs, and medication adherence in patients with COPD initiating treatment with umeclidinium/vilanterol (UMEC/VI) or tiotropium (TIO). METHODS: This retrospective matched cohort study selected patients from Optum's de-identified Clinformatics Data Mart database who initiated maintenance treatment with UMEC/VI or TIO between 01/01/2014 and 12/31/2017 (index date defined as the first dispensing). Eligible patients were ≥ 40 years of age and had ≥ 12 months continuous health plan coverage pre- and post-index; ≥ 1 medical claim for COPD pre-index or on the index date; no moderate/severe COPD-related exacerbations on the index date; no asthma diagnosis pre- or post-index; no maintenance medication fills containing inhaled corticosteroids, long-acting ß2-agonists, or long-acting muscarinic antagonists pre-index or on the index date; and no fills for both UMEC/VI and TIO on the index date. Outcomes included time-to-first (Kaplan-Meier analysis) and rates of on-treatment COPD-related moderate/severe exacerbations, medication adherence (proportion of days covered [PDC] and proportion of adherent patients [PDC ≥ 0.8]), and COPD-related medical costs per patient per month (PPPM). Propensity score matching was used to adjust for potential confounders. RESULTS: Each cohort included 3929 matched patients. Kaplan-Meier rates of on-treatment COPD-related exacerbations were similar between cohorts (hazard ratio at 12 months; overall: 0.93, moderate: 0.92, severe: 1.07; all p > 0.05). UMEC/VI versus TIO initiators had significantly higher adherence (mean PDC: 0.44 vs 0.37; p < 0.001; proportion with PDC ≥ 0.8: 22.0% vs 16.4%; p< 0.001) and significantly lower mean on-treatment COPD-related total medical costs ($867 vs $1095 PPPM; p = 0.028), driven by lower outpatient visit costs. CONCLUSIONS: These findings provide valuable information for physicians considering UMEC/VI or TIO as initial maintenance therapy options for patients with COPD.

BBB07 contributes to, but is not essential for, Borrelia burgdorferi infection in mice.

Borrelia burgdorferi, a causative agent of Lyme disease, encodes a protein BBB07 on the genomic plasmid cp26. BBB07 was identified as a candidate integrin ligand based on the presence of an RGD tripeptide motif, which is present in a number of mammalian ligands for ß1 and ß3 integrins . Previous work demonstrated that BBB07 in recombinant form binds to ß1 integrins and induces inflammatory responses in synovial cells in culture. Several transposon mutants in bbb07 were attenuated in an in vivo screen of the transposon library in mice. We therefore tested individual transposon mutant clones in single-strain infections in mice and found that they were attenuated in terms of ID50 but did not have significantly reduced tissue burdens in mice. Based on data presented here we conclude that BBB07 is not essential for, but does contribute to, B. burgdorferi infectivity in mice.

Impact of mepolizumab on exacerbations in severe asthma: Results from a U.S. insurance claims data base.

Background: In controlled clinical studies, mepolizumab has been shown to reduce exacerbation rates and the use of oral corticosteroids as well as improve asthma control and health-related quality of life compared with placebo in patients with severe eosinophilic asthma. However, real-world data on the impact of mepolizumab on clinical outcomes are limited. Objective: To evaluate the effect of mepolizumab on asthma exacerbations and asthma exacerbation-related costs in patients with severe asthma in U.S. clinical practice. Methods: This retrospective cohort study used U.S. administrative claims data from patients ages ≥12 years and with severe asthma at mepolizumab treatment initiation (index date; identification period, January 2015-June 2017) who had received two or more mepolizumab administrations within 180 days of the index date and had no evidence of treatment with another asthma biologic. The exacerbation rate and exacerbation-related costs were assessed in both the 12 months before mepolizumab initiation (baseline period) and the following 12 months (follow-up period). A clinical trial-like cohort was identified, defined as patients with two or more baseline exacerbations and ≥10 administrations during follow-up. Results: A total of 201 patients were included in the overall population and 74 patients in the clinical trial-like cohort. Mepolizumab significantly reduced the exacerbation rate between the baseline and follow-up periods in both the overall population and the clinical trial-like cohort (p < 0.001), which corresponded to 33.6% and 48.6% reductions, respectively. The rate of exacerbations in patients who required hospitalization between the baseline and follow-up periods was also reduced by 35.3% (p = 0.080) and 68.2% (p = 0.015) in the overall population and in the clinical trial-like cohort, respectively. Cost data were inconclusive. Conclusion: This study, which used real-world data, demonstrated that mepolizumab is associated with reductions in asthma exacerbations, in line with the findings from controlled clinical studies. These results provided further evidence of the effectiveness of mepolizumab in a real-world setting.

Disentangling monitoring programs: design, analysis, and application considerations.

Monitoring programs are an essential tool for assessing and informing conservation efforts but the methods used to gather monitoring data directly influence results. This presents a challenge to conservation professionals when deciding on existing data to inform a given question. We illustrate the challenges of using monitoring data by comparing population trends from two large-scale avian monitoring programs in the western United States: the Breeding Bird Survey and Integrated Monitoring in Bird Conservation Regions programs. We used publicly available data to compare trend trajectory between 2008 and 2015 for 148 species across Colorado, Montana, and Wyoming. Trends were inconsistent for 62% of the comparisons, with species having opposite trends in 21 cases. The inconsistencies found within our species comparisons reflect the inherent differences between program sampling design and analytical approach. Periodically revisiting how and why we monitor natural resources is necessary to advance conservation and management as the lessons learned from long-standing programs guide the development of more recent efforts. Our results emphasize that prior to management actions and policy decisions, managers must be aware of both the sampling design and appropriate ecological inference of any monitoring program.

Effects of systemic corticosteroids on blood eosinophil counts in asthma: real-world data.

Introduction: Systemic corticosteroids (SCS) are effective anti-inflammatory therapies for patients with severe or persistent asthma. Use of SCS reduces blood eosinophil counts; the magnitude and duration of reduction in real-world settings needs further investigation. Objective: To examine the SCS effect on blood eosinophil counts over time among patients with asthma in a real-world setting. Methods: This retrospective study used Reliant Medical Group (Worcester, MA) electronic medical records between January 2011 and December 2015. Patients aged ≥12 years with ≥1 SCS prescription (first: index date), ≥1 asthma diagnosis, and ≥1 eosinophil count in each 12-month pre- and post-index periods were included for the study. Endpoints included SCS treatment patterns, time to SCS discontinuation, and changes in index blood eosinophil counts (≥150, ≥300, and ≥400 cells/µL) with SCS initiation and discontinuation. Results: At index visit, 642 of 1198 included patients had a blood eosinophil count ≥150 cells/µL. After an average initial SCS prescription of 35 mg/day, mean (% change) eosinophil counts at month 1 in the ≥150, ≥300, and≥400 cells/µL subgroups decreased from index by 112 (-30%), 202 (-34%), and 290 (-36%) cells/µL, respectively. Of the patients with an eosinophil count ≥150 cells/µL at index, who discontinued SCS within 7, 14, or 21 days after the index date, 21%, 26%, and 25% had an eosinophil count <150 cells/µL 1-month post-index, respectively. Conclusion: Blood eosinophil counts decreased following initiation of SCS therapy and had not returned to index levels several weeks after SCS discontinuation. The time frame of SCS discontinuation is an important consideration when identifying patients with eosinophilic asthma.

Disease burden in patients with asthma before initiating biologics: A retrospective cohort database study.

Background: Real-world data on the characteristics and burden of disease among patients with asthma before receiving asthma-specific biologics would improve the understanding of the use of these therapies in a clinical setting. Currently, limited data are available on the use of mepolizumab and omalizumab for the treatment of asthma. Objective: To determine the characteristics and disease burden among patients with asthma before initiating treatment with mepolizumab or omalizumab. Methods: This was a retrospective cohort analysis of commercial and Medicare Advantage Plan members from a medical claims database with a new claim for mepolizumab or omalizumab between January 1, 2015, and March 31, 2017 (GSK ID: HO-17-18283). Eligible patients had a diagnosis of asthma and continuous enrollment in the health plan, with clinical and pharmacy benefits for 12 months before initiating asthma-specific biologic treatment (baseline period), and no diagnosis of chronic idiopathic urticaria during the baseline period. Patient characteristics, exacerbations, and asthma-related health care resource utilization and costs were assessed during the baseline period. Results: Overall, 188 and 901 patients prescribed mepolizumab and omalizumab, respectively, were included. In the 12 months before initiating asthma-specific biologic therapy, the patients prescribed mepolizumab were older, had higher blood eosinophil counts, more-frequent exacerbations (2.9 versus 2.0 exacerbations/year; p < 0.001), and more inhaled corticosteroid and systemic corticosteroid use compared with those prescribed omalizumab. Overall, asthma-related health-care resource utilization and costs were similar across both treatment cohorts, although patients prescribed mepolizumab had more pharmacy fills, higher pharmacy costs, and lower clinic costs compared with patients prescribed omalizumab (20.8 versus 16.9 fills, $4504 versus $3102, and $1816 versus $2709, respectively; all p < 0.001). Conclusion: In the 12 months before initiating asthma-specific biologic therapy, the patients prescribed mepolizumab may have a greater disease burden than those prescribed omalizumab. Overall, health-care resource utilization and costs were broadly similar across both treatment cohorts.

Assessment of symptom burden and adherence to respiratory medications in individuals self-reporting a diagnosis of COPD within a community pharmacy setting.

OBJECTIVES: Data on symptom burden or medication adherence in patients with chronic obstructive pulmonary disease (COPD) within a community pharmacy setting are limited. This study assessed symptom burden and adherence to respiratory medications in individuals reporting COPD, chronic bronchitis, or emphysema diagnoses visiting community pharmacies. DESIGN: This cross-sectional study enrolled participants visiting 35 community pharmacies in Missouri (October 2016 to April 2017). PARTICIPANTS: Eligible participants (aged 40 years or more with a self-reported history of COPD, prescription for at least 1 COPD maintenance medication during the previous 12 months, and able to complete an English questionnaire) were identified from pharmacy dispensing records. MAIN OUTCOME MEASURES: Participants completed a questionnaire assessing demographics, clinical characteristics, health literacy, COPD Assessment Test (CAT) modified Medical Research Council (mMRC) dyspnea scale scores, and exacerbation history. Recent spirometry data were obtained, if available, from participants' physicians. COPD was classified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2016 criteria. Medication adherence was assessed as proportion of days covered (PDC) from dispensing records. RESULTS: Of 682 participants (mean age 63.0 years; 57% female) with available pharmacy data, 251 (36.8%) had available spirometry data. Most participants had mMRC scores ≥ 2 (60.9%) and CAT scores ≥ 10 (90.2%); 57.2% reported at least 2 moderate or 1 or more severe exacerbations within the previous 12 months. GOLD classifications varied depending on the scale used (mMRC vs. CAT); more participants were classified as group C/D than group A/B, with the highest proportion classified as group D (higher symptom burden and exacerbation risk). Mean PDC was 0.46 ± 0.37; only 28.7% of participants were adherent (PDC ≥ 80%) to at least 1 COPD maintenance medication. CONCLUSION: Individuals self-reporting a COPD diagnosis receiving respiratory medications from community pharmacies in Missouri have a high symptom burden and low medication adherence. Further research should determine reasons for low adherence and ways to reduce COPD symptoms.

Characterization of Stress and Innate Immunity Resistance of Wild-Type and Δp66 Borrelia burgdorferi.

Borrelia burgdorferi is a causative agent of Lyme disease, the most common arthropod-borne disease in the United States. B. burgdorferi evades host immune defenses to establish a persistent, disseminated infection. Previous work showed that P66-deficient B. burgdorferi (Δp66) is cleared quickly after inoculation in mice. We demonstrate that the Δp66 strain is rapidly cleared from the skin inoculation site prior to dissemination. The rapid clearance of Δp66 bacteria is not due to inherent defects in multiple properties that might affect infectivity: bacterial outer membrane integrity, motility, chemotactic response, or nutrient acquisition. This led us to the hypothesis that P66 has a role in mouse cathelicidin-related antimicrobial peptide (mCRAMP; a major skin antimicrobial peptide) and/or neutrophil evasion. Neither wild-type (WT) nor Δp66 B. burgdorferi was susceptible to mCRAMP. To examine the role of neutrophil evasion, we administered neutrophil-depleting antibody anti-Ly6G (1A8) to C3H/HeN mice and subsequently monitored the course of B. burgdorferi infection. Δp66 mutants were unable to establish infection in neutrophil-depleted mice, suggesting that the important role of P66 during early infection is through another mechanism. Neutrophil depletion did not affect WT B. burgdorferi bacterial burdens in the skin (inoculation site), ear, heart, or tibiotarsal joint at early time points postinoculation. This was unexpected given that prior in vitro studies demonstrated neutrophils phagocytose and kill B. burgdorferi These data, together with our previous work, suggest that despite the in vitro ability of host innate defenses to kill B. burgdorferi, individual innate immune mechanisms have limited contributions to controlling early B. burgdorferi infection in the laboratory model used.

Integrin binding by Borrelia burgdorferi†P66 facilitates dissemination but is not required for infectivity.

P66, a Borrelia burgdorferi surface protein with porin and integrin-binding activities, is essential for murine infection. The role of P66 integrin-binding activity in B. burgdorferi infection was investigated and found to affect transendothelial migration. The role of integrin binding, specifically, was tested by mutation of two amino acids (D205A,D207A) or deletion of seven amino acids (Del202-208). Neither change affected surface localization or channel-forming activity of P66, but both significantly reduced binding to αv ß3 . Integrin-binding deficient B. burgdorferi strains caused disseminated infection in mice at 4 weeks post-subcutaneous inoculation, but bacterial burdens were significantly reduced in some tissues. Following intravenous inoculation, the Del202-208 bacteria were below the limit of detection in all tissues assessed at 2 weeks post-inoculation, but bacterial burdens recovered to wild-type levels at 4 weeks post-inoculation. The delay in tissue colonization correlated with reduced migration of the Del202-208 strains across microvascular endothelial cells, similar to Δp66 bacteria. These results indicate that integrin binding by P66 is important to efficient dissemination of B. burgdorferi, which is critical to its ability to cause disease manifestations in incidental hosts and to its maintenance in the enzootic cycle.

Direct translocation of staphylococci from the skin surface to deep organs.

BACKGROUND: Staphylococcus aureus can invade the bloodstream and cause bacteremic infections, but this organism frequently produces serious deep infections without bacteremia or an identifiable portal of entry. METHODS: We used experimental cutaneous S. aureus infections in mice to determine if the bacteria could reach deep organs without travel through the bloodstream. RESULTS: After skin surface application the bacteria rapidly distributed to lymph nodes, spleen, kidneys and other organs. In these animals, blood cultures were negative, dissemination was more efficient after surface application than injection near dermal blood vessels, and kidney bacterial localization sites were unlike those of bacteremic infections. Whereas normal mice eventually cleared bacteria from the deep sites, those with prolonged immunosuppression became moribund from these infections; they also had negative blood cultures and kidney localization not consistent with hematogenous dissemination. Bacteria were also found in the intervening abdominal wall outside the spleen and kidney sites, suggesting direct movement of the organisms from the skin surface through connecting tissues. CONCLUSIONS: Although capable of hematogenous dissemination, S. aureus can also spread from skin to deep organs by a non-bacteremic process. In this case the bacteria appear to migrate directly from the skin surface to the deep organs below.

Impact of Mepolizumab on Exacerbations in the US Medicare Population.

BACKGROUND: Asthma is a common chronic respiratory disorder associated with significant disease and economic burden. Mepolizumab is an anti-IL-5 mAb approved for use as an add-on treatment in patients with severe eosinophilic asthma. OBJECTIVE: To assess the impact of mepolizumab initiation on asthma exacerbation frequency, oral corticosteroid (OCS) use, and asthma exacerbation-related costs in a US Medicare population. METHODS: This was a retrospective cohort study of mepolizumab claims from patients with asthma in the Centers for Medicare and Medicaid Services Medicare database carried out between January 2016 and December 2018. The index date (first claim for mepolizumab) was required to occur between January and December 2017. The baseline and follow-up periods were the 12 months before and 12 months after the index, respectively. Outcomes included changes in the proportion of patients experiencing exacerbations (primary), OCS use (secondary), and asthma exacerbation-related costs during the baseline and follow-up periods. RESULTS: The study identified 1,278 patients (mean age, 67.9 years; 65% female) with one or more prescription or administration claim for mepolizumab who were eligible for study inclusion. There was a significant relative reduction in the proportion of patients with an asthma exacerbation (27%; P < .0001) in the follow-up versus baseline period. Similarly, a lower proportion of patients received OCS for asthma (16% relative reduction; P < .0001), fewer patients were chronic OCS users (5 mg/day or more; 48% relative reduction; P < .0001), and there was a significant decrease in asthma exacerbation-related costs (total reduction, $888; P = .0002) during the follow-up versus the baseline period. CONCLUSION: Mepolizumab reduced exacerbations, OCS use, and exacerbation-related healthcare costs in a US Medicare population, confirming its benefits in this specific population with severe asthma.

Heterologous production of the adhesin LIC13411 from pathogenic Leptospira facilitates binding of non-pathogenic Leptospira in vitro and in vivo.

Leptospirosis is an important cause of morbidity and mortality worldwide. Disease severity ranges from asymptomatic colonization to widespread hemorrhage and multiorgan dysfunction. The causative agents, Leptospira spp., are zoonotic Gram-negative spirochetes. One important step in pathogenesis is binding of bacterial adhesins to host components. Previously our laboratory identified two L. interrogans candidate adhesins, LIC11574 and LIC13411, that bind to VE-cadherin in vitro. In the current study, we demonstrate the ability of two strains of pathogenic L. interrogans to disrupt the localization of VE-cadherin, a protein important to maintaining inter-endothelial junctions. Purified MBP-LIC11574 and MBP-LIC13411 bind human dermal microvascular endothelial cells in a pattern reminiscent of VE-cadherin, but do not disrupt VE-cadherin localization. Genes encoding the candidate adhesins from pathogenic Leptospira were cloned in an overexpression vector and introduced into non-pathogenic L. biflexa, creating gain-of-function strains producing LIC11574 or LIC13411. Protein production and localization to the outer membrane were confirmed by Triton X-114 fractionation. Although these strains do not disrupt VE-cadherin localization, production of LIC13411 increases binding of non-pathogenic Leptospira to human endothelial cells and specifically to VE-cadherin. In a short-term murine model of infection, LIC13411 production led to increased burdens of the non-pathogen in the lung, liver, kidney, and bladder. These data confirm the role of LIC13411 as an adhesin in Leptospira spp. and implicate it in dissemination to multiple organs. Importantly, anti-adhesin therapy has been shown to have many benefits over classical antibiotics. Taken together, this work provides novel insight into the pathogenesis of Leptospira spp. and identifies LIC13411 as a potential prophylactic and therapeutic target.

Hematogenous dissemination of pathogenic and non-pathogenic Leptospira in a short-term murine model of infection.

Leptospirosis is an emerging zoonosis caused by pathogenic Leptospira spp. Because rodents are natural hosts of Leptospira, rodent models of pathogenesis have been limited, but are valuable to understand infection in reservoir animals even in the absence of disease. Mouse models of infection provide advantages due to genetic tractability, so developing murine models of Leptospira infection is crucial for further understanding the biology of this organism. Previously our laboratory developed a short-term murine model of Borrelia burgdorferi hematogenous dissemination to investigate the role of adhesion proteins on bacterial survival and dissemination within a host. Here we adapt this model to Leptospira. C3H/HeJ mice are anesthetized, inoculated intravenously, and then bacteria are allowed to circulate for up to twenty-four hours. Mice are euthanized, perfused with saline, and tissues are harvested for culture and DNA purification. Bacterial burdens are determined by quantitative PCR. Reproducible burdens of bacteria were found in tissues upon inoculation with pathogens and non-pathogens, demonstrating the utility of this model to probe different Leptospira species and strains. Pathogenic L. interrogans has a significantly higher burden in blood, liver, kidney, and bladder at one-hour post-inoculation when compared to non-pathogenic L. biflexa. Colonization of the kidney is essential to the life cycle of pathogenic Leptospira in nature. Measurable burdens of non-pathogenic L. biflexa were found in numerous organs and live leptospires were recovered from blood samples for at least three hours post-inoculation, contrary to the previous belief that non-pathogenic leptospires are rapidly cleared. This short-term murine model of Leptospira hematogenous dissemination will allow for the interrogation of virulence factors potentially important for tissue colonization and evasion of host defenses, and represents a novel animal model for investigating determinants of Leptospira infection.

Oral corticosteroid-sparing effects of mepolizumab in severe eosinophilic asthma: evidence from randomized controlled trials and real-world studies.

Oral corticosteroids (OCS) have long been a mainstay of treatment for asthma exacerbations and chronic severe asthma. However, it is increasingly recognized that both long-term and short-term OCS use are directly associated with a wide range of serious adverse effects, and as such OCS-sparing treatment alternatives are now widely recommended for patients with severe asthma. While several international guidelines recommend these treatments, guidance on OCS tapering, and which patients are most likely to tolerate OCS reduction and/or discontinuation, is still lacking. Several biologics have demonstrated efficacy in patients with OCS-dependent asthma. One OCS-sparing treatment is the anti-interleukin-5 monoclonal antibody mepolizumab, which is approved for the treatment of severe eosinophilic asthma. In addition to improved exacerbation rates, asthma control, quality of life, and lung function among patients with severe eosinophilic asthma, mepolizumab also has an OCS-sparing effect, which has been demonstrated in randomized controlled trials and real-world studies. Both physicians and patients express concerns about the adverse effects of OCS, and additional data from the randomized, controlled SIRIUS trial (NCT01691508) highlight the high level of concern among patients regarding OCS-related burden. In this article, we discuss current guidance on OCS-sparing strategies for patients with severe asthma, provide a summary of the available evidence of the OCS-sparing effect of mepolizumab, and highlight patient and physician perspectives on the use of OCS and OCS-sparing treatments in severe asthma.