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Boumasmoud M, Dengler Haunreiter V, Schweizer TA, Meyer L, Chakrakodi B, Schreiber PW, Seidl K, Kühnert D, Kouyos RD, Zinkernagel AS. Genomic Surveillance of Vancomycin-Resistant Enterococcus faecium Reveals Spread of a Linear Plasmid Conferring a Nutrient Utilization Advantage. mBio 2022; 13:e0377121. [PMID: 35343787 PMCID: PMC9040824 DOI: 10.1128/mbio.03771-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 02/25/2022] [Indexed: 12/12/2022] Open
Abstract
Healthcare-associated outbreaks of vancomycin-resistant Enterococcus faecium (VREfm) are a worldwide problem with increasing prevalence. The genomic plasticity of this hospital-adapted pathogen contributes to its efficient spread despite infection control measures. Here, we aimed to identify the genomic and phenotypic determinants of health care-associated transmission of VREfm. We assessed the VREfm transmission networks at the tertiary-care University Hospital of Zurich (USZ) between October 2014 and February 2018 and investigated microevolutionary dynamics of this pathogen. We performed whole-genome sequencing for the 69 VREfm isolates collected during this time frame and assessed the population structure and variability of the vancomycin resistance transposon. Phylogenomic analysis allowed us to reconstruct transmission networks and to unveil external or wider transmission networks undetectable by routine surveillance. Notably, it unveiled a persistent clone, sampled 31 times over a 29-month period. Exploring the evolutionary dynamics of this clone and characterizing the phenotypic consequences revealed the spread of a variant with decreased daptomycin susceptibility and the acquired ability to utilize N-acetyl-galactosamine (GalNAc), one of the primary constituents of the human gut mucins. This nutrient utilization advantage was conferred by a novel plasmid, termed pELF_USZ, which exhibited a linear topology. This plasmid, which was harbored by two distinct clones, was transferable by conjugation. Overall, this work highlights the potential of combining epidemiological, functional genomic, and evolutionary perspectives to unveil adaptation strategies of VREfm. IMPORTANCE Sequencing microbial pathogens causing outbreaks has become a common practice to characterize transmission networks. In addition to the signal provided by vertical evolution, bacterial genomes harbor mobile genetic elements shared horizontally between clones. While macroevolutionary studies have revealed an important role of plasmids and genes encoding carbohydrate utilization systems in the adaptation of Enterococcus faecium to the hospital environment, mechanisms of dissemination and the specific function of many of these genetic determinants remain to be elucidated. Here, we characterize a plasmid providing a nutrient utilization advantage and show evidence for its clonal and horizontal spread at a local scale. Further studies integrating epidemiological, functional genomics, and evolutionary perspectives will be critical to identify changes shaping the success of this pathogen.
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Maccio U, Zinkernagel AS, Schuepbach R, Probst-Mueller E, Frontzek K, Brugger SD, Hofmaenner DA, Moch H, Varga Z. Long-Term Persisting SARS-CoV-2 RNA and Pathological Findings: Lessons Learnt From a Series of 35 COVID-19 Autopsies. Front Med (Lausanne) 2022; 9:778489. [PMID: 35223894 PMCID: PMC8865372 DOI: 10.3389/fmed.2022.778489] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 01/04/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Long-term sequelae of coronavirus disease 2019 (COVID-19), including the interaction between persisting viral-RNA and specific tissue involvement, pose a challenging issue. In this study, we addressed the chronological correlation (after first clinical diagnosis and postmortem) between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA and organ involvement. METHODS The presence of postmortem SARS-CoV-2 RNA from 35 complete COVID-19 autopsies was correlated with the time interval between the first diagnosis of COVID-19 and death and with its relationship to morphologic findings. RESULTS Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA can be evident up to 40 days after the first diagnosis and can persist to 94 hours after death. Postmortem SARS-CoV-2 RNA was mostly positive in lungs (70%) and trachea (69%), but all investigated organs were positive with variable frequency. Late-stage tissue damage was evident up to 65 days after initial diagnosis in several organs. Positivity for SARS-CoV-2 RNA in pulmonary swabs correlated with diffuse alveolar damage (p = 0.0009). No correlation between positive swabs and other morphologic findings was present. Cerebral (p = 0.0003) and systemic hemorrhages (p = 0.009), cardiac thrombi (p = 0.04), and ischemic events (p = 0.03) were more frequent in the first wave, whereas bacterial pneumonia (p = 0.03) was more prevalent in the second wave. No differences in biometric data, clinical comorbidities, and other autopsy findings were found. CONCLUSIONS Our data provide evidence not only of long-term postmortem persisting SARS-CoV-2 RNA but also of tissue damage several weeks after the first diagnosis of SARS-CoV-2 infection. Additional conditions, such as concomitant bacterial pulmonary superinfection, lung aspergillosis, thromboembolic phenomena, and hemorrhages can further worsen tissue damage.
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Hofmaenner DA, Wendel Garcia PD, Blum MR, David S, Schuepbach RA, Buehler PK, Frey PM, Zinkernagel AS, Brugger SD. The importance of intravenous immunoglobulin treatment in critically ill patients with necrotizing soft tissue infection: a retrospective cohort study. BMC Infect Dis 2022; 22:168. [PMID: 35189821 PMCID: PMC8862556 DOI: 10.1186/s12879-022-07135-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 02/09/2022] [Indexed: 11/16/2022] Open
Abstract
Background Necrotizing soft-tissue infections are infections with high mortality. The use of immunoglobulins within a combination therapy including broad-spectrum antibiotics has been debated. We assessed potential benefits of immunoglobulins and hypothesized that they were associated with a treatment benefit in a high-resource setting. Methods Patients with necrotizing soft-tissue infection hospitalized in the tertiary intensive care unit of the University Hospital of Zurich, Switzerland, between 2008 and 2020 were included retrospectively. The association between immunoglobulin administration and in-hospital survival, intensive care unit length of stay, the incidences of acute renal failure, acute respiratory distress syndrome and septic shock were analyzed. Results After adjustment for confounders, no difference for in-hospital survival (hazard ratio 2.20, 95% confidence interval [CI] 0.24–20.20, p = 0.5), intensive care unit length of stay (subhazard ratio [SHR] 0.90, CI 0.41–1.98, p = 0.8) and the development of acute respiratory distress syndrome (SHR 1.2, CI 0.36–4.03, p = 0.77) was observed in patients with or without immunoglobulin treatment. The Simplified Acute Physiology Score II, the risk of developing acute renal failure (SHR 2.86, CI 1.33–6.15, p = 0.01) and septic shock (SHR 1.86, CI 1.02–3.40, p = 0.04) was higher in patients treated with immunoglobulins, possibly reflecting a higher disease severity beyond measured confounders. Conclusions No clear evidence for a benefit of immunoglobulins in our cohort with consistent antibiotic use was found. Patients receiving immunoglobulins appeared more severely ill. Complementary to high treatment standards and appropriate antibiotics including beta lactams and protein synthesis inhibitors, immunoglobulins should be administered on a case-to-case basis, at least while more evidence from larger randomized controlled trials is missing.
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Bär J, Boumasmoud M, Mairpady Shambat S, Vulin C, Huemer M, Schweizer TA, Gómez-Mejia A, Eberhard N, Achermann Y, Zingg PO, Mestres C, Brugger SD, Schuepbach RA, Kouyos RD, Hasse B, Zinkernagel AS. Quantification of within-patient Staphylococcus aureus phenotypic heterogeneity as a proxy for presence of persisters across clinical presentations. Clin Microbiol Infect 2022; 28:1022.e1-1022.e7. [DOI: 10.1016/j.cmi.2022.01.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 01/19/2022] [Accepted: 01/23/2022] [Indexed: 12/21/2022]
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Huang A, Cicin-Sain C, Pasin C, Epp S, Audigé A, Müller NJ, Nilsson J, Bankova A, Wolfensberger N, Vilinovszki O, Nair G, Hockl P, Schanz U, Kouyos RD, Hasse B, Zinkernagel AS, Trkola A, Manz MG, Abela IA, Müller AMS. Antibody Response to SARS-CoV-2 Vaccination in Patients Following Allogeneic Hematopoietic Cell Transplantation. Transplant Cell Ther 2022; 28:214.e1-214.e11. [PMID: 35092892 PMCID: PMC8802693 DOI: 10.1016/j.jtct.2022.01.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 01/06/2023]
Abstract
Vaccines against SARS-CoV-2 have been rapidly approved. Although pivotal studies were conducted in healthy volunteers, little information is available on the safety and efficacy of mRNA vaccines in immunocompromised patients, including recipients of allogeneic hematopoietic cell transplantation (allo-HCT). Here we used a novel assay to analyze patient- and transplantation-related factors and their influence on immune responses to SARS-CoV-2 vaccination over an extended period (up to 6 months) in a large and homogenous group of allo-HCT recipients at a single center in Switzerland. We examined longitudinal antibody responses to SARS-CoV-2 vaccination with BNT162b2 (BioNTech/Pfizer) and mRNA-1273 (Moderna) in 110 allo-HCT recipients and 86 healthy controls. Seroprofiling recording IgG, IgA, and IgM reactivity against SARS-CoV-2 antigens (receptor-binding domain, spike glycoprotein subunits S1 and S2, and nucleocapsid protein) was performed before vaccination, before the second dose, and at 1, 3, and 6 months after the second dose. Patients were stratified to 3 groups: 3 to 6 months post-allo-HCT, 6 to 12 months post-allo-HCT, and >12 months post-allo-HCT. Patients in the 3 to 6 months and 6 to 12 months post-allo-HCT groups developed significantly lower antibody titers after vaccination compared with patients in the >12 months post-allo-HCT group and healthy controls (P < .001). Within the cohort of allo-HCT recipients, patients age >65 years (P = .030), those receiving immunosuppression for prevention or treatment of graft-versus-host disease (GVHD) (P = .033), and patients with relapsed disease (P = .014) displayed low humoral immune responses to the vaccine. In contrast, the intensity of the conditioning regimen, underlying disease (myeloid/lymphoid/other), and presence of chronic GVHD had no impact on antibody levels. Antibody titers achieved the highest levels at 1 month after the second dose of the vaccine but waned substantially in all transplantation groups and healthy controls over time. This analysis of long-term vaccine antibody response is of critical importance to allo-HCT recipients and transplant physicians to guide treatment decisions regarding revaccination and social behavior during the SARS-CoV-2 pandemic.
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Mairpady Shambat S, Gómez-Mejia A, Schweizer TA, Huemer M, Chang CC, Acevedo C, Bergada-Pijuan J, Vulin C, Hofmaenner DA, Scheier TC, Hertegonne S, Parietti E, Miroshnikova N, Wendel Garcia PD, Hilty MP, Buehler PK, Schuepbach RA, Brugger SD, Zinkernagel AS. Hyperinflammatory environment drives dysfunctional myeloid cell effector response to bacterial challenge in COVID-19. PLoS Pathog 2022; 18:e1010176. [PMID: 35007290 PMCID: PMC8782468 DOI: 10.1371/journal.ppat.1010176] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 01/21/2022] [Accepted: 12/06/2021] [Indexed: 02/06/2023] Open
Abstract
COVID-19 displays diverse disease severities and symptoms including acute systemic inflammation and hypercytokinemia, with subsequent dysregulation of immune cells. Bacterial superinfections in COVID-19 can further complicate the disease course and are associated with increased mortality. However, there is limited understanding of how SARS-CoV-2 pathogenesis and hypercytokinemia impede the innate immune function against bacterial superinfections. We assessed the influence of COVID-19 plasma hypercytokinemia on the functional responses of myeloid immune cells upon bacterial challenges from acute-phase COVID-19 patients and their corresponding recovery-phase. We show that a severe hypercytokinemia status in COVID-19 patients correlates with the development of bacterial superinfections. Neutrophils and monocytes derived from COVID-19 patients in their acute-phase showed an impaired intracellular microbicidal capacity upon bacterial challenges. The impaired microbicidal capacity was reflected by abrogated MPO and reduced NETs production in neutrophils along with reduced ROS production in both neutrophils and monocytes. Moreover, we observed a distinct pattern of cell surface receptor expression on both neutrophils and monocytes, in line with suppressed autocrine and paracrine cytokine signaling. This phenotype was characterized by a high expression of CD66b, CXCR4 and low expression of CXCR1, CXCR2 and CD15 in neutrophils and low expression of HLA-DR, CD86 and high expression of CD163 and CD11b in monocytes. Furthermore, the impaired antibacterial effector function was mediated by synergistic effect of the cytokines TNF-α, IFN-γ and IL-4. COVID-19 patients receiving dexamethasone showed a significant reduction of overall inflammatory markers in the plasma as well as exhibited an enhanced immune response towards bacterial challenge ex vivo. Finally, broad anti-inflammatory treatment was associated with a reduction in CRP, IL-6 levels as well as length of ICU stay and ventilation-days in critically ill COVID-19 patients. Our data provides insights into the transient functional dysregulation of myeloid immune cells against subsequent bacterial infections in COVID-19 patients and describe a beneficial role for the use of dexamethasone in these patients.
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Schweizer TA, Mairpady Shambat S, Vulin C, Hoeller S, Acevedo C, Huemer M, Gomez‐Mejia A, Chang C, Baum J, Hertegonne S, Hitz E, Scheier TC, Hofmaenner DA, Buehler PK, Moch H, Schuepbach RA, Brugger SD, Zinkernagel AS. Blunted sFasL signalling exacerbates TNF-driven neutrophil necroptosis in critically ill COVID-19 patients. Clin Transl Immunology 2021; 10:e1357. [PMID: 34938538 PMCID: PMC8665925 DOI: 10.1002/cti2.1357] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 10/26/2021] [Accepted: 11/03/2021] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Critically ill coronavirus disease 2019 (COVID-19) patients are characterised by a severely dysregulated cytokine profile and elevated neutrophil counts, impacting disease severity. However, it remains unclear how neutrophils contribute to pathophysiology during COVID-19. Here, we assessed the impact of the dysregulated cytokine profile on the regulated cell death (RCD) programme of neutrophils. METHODS Regulated cell death phenotype of neutrophils isolated from critically ill COVID-19 patients or healthy donors and stimulated with COVID-19 or healthy plasma ex vivo was assessed by flow cytometry, time-lapse microscopy and cytokine multiplex analysis. Immunohistochemistry of COVID-19 patients and control biopsies were performed to assess the in situ neutrophil RCD phenotype. Plasma cytokine levels of COVID-19 patients and healthy donors were measured by multiplex analysis. Clinical parameters were correlated to cytokine levels of COVID-19 patients. RESULTS COVID-19 plasma induced a necroptosis-sensitive neutrophil phenotype, characterised by cell lysis, elevated release of damage-associated molecular patterns (DAMPs), increased receptor-interacting serine/threonine-protein kinase (RIPK) 1 levels and mixed lineage kinase domain-like pseudokinase (MLKL) involvement. The occurrence of neutrophil necroptosis MLKL axis was further confirmed in COVID-19 thrombus and lung biopsies. Necroptosis was induced by the tumor necrosis factor receptor 1 (TNFRI)/TNF-α axis. Moreover, reduction of soluble Fas ligand (sFasL) levels in COVID-19 patients and hence decreased signalling to Fas directly increased RIPK1 levels, exacerbated TNF-driven necroptosis and correlated with disease severity, which was abolished in patients treated with glucocorticoids. CONCLUSION Our results suggest a novel role for sFasL signalling in the TNF-α-induced RCD programme in neutrophils during COVID-19 and a potential therapeutic target to curb inflammation and thus influence disease severity and outcome.
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Van Hemelrijck M, Frank M, Zinkernagel AS, Buechel R, Sromicki J, Wilhelm MJ, Klein H, Hasse B, Mestres CA. Sternectomy for Candida albicans sternal osteomyelitis after left ventricular assist device implantation. Indian J Thorac Cardiovasc Surg 2021; 37:573-576. [PMID: 34511767 PMCID: PMC8387541 DOI: 10.1007/s12055-021-01144-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/30/2020] [Accepted: 01/06/2021] [Indexed: 11/25/2022] Open
Abstract
Fungal osteomyelitis is an uncommon complication after cardiac surgery and associated with high mortality. A case of Candida albicans and Staphylococcus epidermidis osteomyelitis with device infection after implantation of a left ventricular assist device in a 60-year-old male patient is presented here. After clinical identification and confirmation with microbiological examinations and fluorodeoxyglucose positron emission tomography (FDG-PET) scan, debridement was performed. Surgical specimens grew C. albicans and S. epidermidis. Fluconazole, daptomycin, and negative pressure wound therapy were initiated, but failed to achieve healing. Total sternectomy and pectoralis flap reconstruction were performed. There was no recurrent infection for C. albicans on a prolonged antifungal regime. The combination of antifungal therapy and aggressive surgical debridement may be useful to control fungal osteomyelitis.
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Leung YKS, Ledergerber B, Eberhard N, Mestres CA, Rancic Z, Zimmermann A, Zbinden R, Brugger SD, Zinkernagel AS, Hasse B. Open wounds and rifampicin therapy are associated with rifampicin resistance among staphylococcal vascular graft/endograft infections. JAC Antimicrob Resist 2021; 3:dlab041. [PMID: 34223108 PMCID: PMC8209986 DOI: 10.1093/jacamr/dlab041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/01/2021] [Indexed: 11/23/2022] Open
Abstract
Background Optimal timing for rifampicin combination therapy in patients with staphylococcal vascular graft/endograft infection (S-VGEI) is unknown. Experts recommend adding rifampicin after lowering bacterial load by surgery and wound closure. Objectives To assess predictors of rifampicin resistance among staphylococci isolated from patients in the Vascular Graft Infection Cohort Study. Methods We included prospective patients with S-VGEI diagnosis from 1 January 2002 to 30 June 2020. We retrospectively assessed determinants of rifampicin resistance using exact logistic regression and described survival with Kaplan–Meier curves. Results We analysed 513 Staphylococcus spp. among 143 predominantly male (82%) patients with a median age of 68 years (IQR 60–75). Thereof, 82 (57%) received a rifampicin combination therapy and 61 (43%) received an antimicrobial therapy without rifampicin. Among 82 patients with rifampicin, 26/26 patients with any rifampicin resistance had open wounds with a strong association of rifampicin resistance with rifampicin treatment while having open wounds (OR 37, 95% CI 6.1 to ∞). Among 75 patients with a rifampicin combination therapy and rifampicin-susceptible staphylococci at S-VGEI diagnosis, 12/12 patients with a secondary rifampicin-resistant isolate had an open wound (OR 14, 95% CI 2.1 to ∞). Conclusions Rifampicin should be started after wound closure due to increased risk of rifampicin resistance observed while having open wounds or second-look surgeries among patients with S-VGEI.
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Buehler PK, Zinkernagel AS, Hofmaenner DA, Wendel Garcia PD, Acevedo CT, Gómez-Mejia A, Mairpady Shambat S, Andreoni F, Maibach MA, Bartussek J, Hilty MP, Frey PM, Schuepbach RA, Brugger SD. Bacterial pulmonary superinfections are associated with longer duration of ventilation in critically ill COVID-19 patients. CELL REPORTS MEDICINE 2021; 2:100229. [PMID: 33748789 PMCID: PMC7955928 DOI: 10.1016/j.xcrm.2021.100229] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/29/2021] [Accepted: 03/09/2021] [Indexed: 01/02/2023]
Abstract
The impact of secondary bacterial infections (superinfections) in coronavirus disease 2019 (COVID-19) is not well understood. In this prospective, monocentric cohort study, we aim to investigate the impact of superinfections in COVID-19 patients with acute respiratory distress syndrome. Patients are assessed for concomitant microbial infections by longitudinal analysis of tracheobronchial secretions, bronchoalveolar lavages, and blood cultures. In 45 critically ill patients, we identify 19 patients with superinfections (42.2%). Superinfections are detected on day 10 after intensive care admission. The proportion of participants alive and off invasive mechanical ventilation at study day 28 (ventilator-free days [VFDs] at 28 days) is substantially lower in patients with superinfection (subhazard ratio 0.37; 95% confidence interval [CI] 0.15–0.90; p = 0.028). Patients with pulmonary superinfections have a higher incidence of bacteremia, virus reactivations, yeast colonization, and required intensive care treatment for a longer time. Superinfections are frequent and associated with reduced VFDs at 28 days despite a high rate of empirical antibiotic therapy. Secondary bacterial infections (superinfections) are found in 42% of patients Bacterial superinfections occur on day 10 after intensive care admission Bacterial superinfections are associated with longer duration of ventilation Bacterial superinfections are mostly caused by Gram-negative bacteria
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Cervia C, Nilsson J, Zurbuchen Y, Valaperti A, Schreiner J, Wolfensberger A, Raeber ME, Adamo S, Weigang S, Emmenegger M, Hasler S, Bosshard PP, De Cecco E, Bächli E, Rudiger A, Stüssi-Helbling M, Huber LC, Zinkernagel AS, Schaer DJ, Aguzzi A, Kochs G, Held U, Probst-Müller E, Rampini SK, Boyman O. Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19. J Allergy Clin Immunol 2021; 147:545-557.e9. [PMID: 33221383 DOI: 10.1101/2020.05.21.108308] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 10/05/2020] [Accepted: 10/20/2020] [Indexed: 05/21/2023]
Abstract
BACKGROUND Whereas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody tests are increasingly being used to estimate the prevalence of SARS-CoV-2 infection, the determinants of these antibody responses remain unclear. OBJECTIVES Our aim was to evaluate systemic and mucosal antibody responses toward SARS-CoV-2 in mild versus severe coronavirus disease 2019 (COVID-19) cases. METHODS Using immunoassays specific for SARS-CoV-2 spike proteins, we determined SARS-CoV-2-specific IgA and IgG in sera and mucosal fluids of 2 cohorts, including SARS-CoV-2 PCR-positive patients (n = 64) and PCR-positive and PCR-negtive health care workers (n = 109). RESULTS SARS-CoV-2-specific serum IgA titers in patients with mild COVID-19 were often transiently positive, whereas serum IgG titers remained negative or became positive 12 to 14 days after symptom onset. Conversely, patients with severe COVID-19 showed a highly significant increase of SARS-CoV-2-specific serum IgA and IgG titers after symptom onset. Very high titers of SARS-CoV-2-specific serum IgA were correlated with severe acute respiratory distress syndrome. Interestingly, some health care workers with negative SARS-CoV-2-specific serum antibody titers showed SARS-CoV-2-specific IgA in mucosal fluids with virus-neutralizing capacity in some cases. SARS-CoV-2-specific IgA titers in nasal fluids were inversely correlated with age. CONCLUSIONS Systemic antibody production against SARS-CoV-2 develops mainly in patients with severe COVID-19, with very high IgA titers seen in patients with severe acute respiratory distress syndrome, whereas mild disease may be associated with transient production of SARS-CoV-2-specific antibodies but may stimulate mucosal SARS-CoV-2-specific IgA secretion.
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Maurer SM, Kursawe L, Rahm S, Prinz J, Zinkernagel AS, Moter A, Kuster SP, Zbinden R, Zingg PO, Achermann Y. Cutibacterium avidum resists surgical skin antisepsis in the groin-a potential risk factor for periprosthetic joint infection: a quality control study. Antimicrob Resist Infect Control 2021; 10:27. [PMID: 33522957 PMCID: PMC7852298 DOI: 10.1186/s13756-021-00883-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 01/05/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The skin commensal Cutibacterium avidum has been recognized as an emerging pathogen for periprosthetic joint infections (PJI). One currently assumes that the early occurring PJIs are a consequence of skin commensals contaminating the peri-implant tissue during surgery. We addressed whether standard skin antisepsis with povidone-iodine/alcohol before total hip arthroplasty (THA) is effective to eliminate colonizing bacteria with focus on C. avidum. METHODS In a single-center, prospective study, we screened all patients for skin colonizing C. avidum in the groin before THA. Only in the patients positive for C. avidum, we preoperatively repeated skin swabs after the first and third skin antisepsis and antibiotic prophylaxis. We also obtained dermis biopsies for microbiology and fluorescence in situ hybridization (FISH). RESULTS Fifty-one out of 60 patients (85%) were colonized on the skin with various bacteria, in particular with C. avidum in 12 out of 60. Skin antisepsis eliminated C. avidum in eight of ten (20%) colonized patients undergoing THA. Deeper skin (dermis) biopsies were all culture negative, but FISH detected single positive ribosome-rich C. avidum in one case near sweat glands. CONCLUSION Standard skin antisepsis was not effective to completely eliminate colonizing C. avidum on the skin in the groin of patients undergoing THA. Colonizing with C. avidum might pose an increased risk for PJI when considering a THA. Novel more effective antisepsis strategies are needed. Trial registration No clinical trial.
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Cervia C, Nilsson J, Zurbuchen Y, Valaperti A, Schreiner J, Wolfensberger A, Raeber ME, Adamo S, Weigang S, Emmenegger M, Hasler S, Bosshard PP, De Cecco E, Bächli E, Rudiger A, Stüssi-Helbling M, Huber LC, Zinkernagel AS, Schaer DJ, Aguzzi A, Kochs G, Held U, Probst-Müller E, Rampini SK, Boyman O. Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19. J Allergy Clin Immunol 2021; 147:545-557.e9. [PMID: 33221383 PMCID: PMC7677074 DOI: 10.1016/j.jaci.2020.10.040] [Citation(s) in RCA: 249] [Impact Index Per Article: 83.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 10/05/2020] [Accepted: 10/20/2020] [Indexed: 01/08/2023]
Abstract
BACKGROUND Whereas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody tests are increasingly being used to estimate the prevalence of SARS-CoV-2 infection, the determinants of these antibody responses remain unclear. OBJECTIVES Our aim was to evaluate systemic and mucosal antibody responses toward SARS-CoV-2 in mild versus severe coronavirus disease 2019 (COVID-19) cases. METHODS Using immunoassays specific for SARS-CoV-2 spike proteins, we determined SARS-CoV-2-specific IgA and IgG in sera and mucosal fluids of 2 cohorts, including SARS-CoV-2 PCR-positive patients (n = 64) and PCR-positive and PCR-negtive health care workers (n = 109). RESULTS SARS-CoV-2-specific serum IgA titers in patients with mild COVID-19 were often transiently positive, whereas serum IgG titers remained negative or became positive 12 to 14 days after symptom onset. Conversely, patients with severe COVID-19 showed a highly significant increase of SARS-CoV-2-specific serum IgA and IgG titers after symptom onset. Very high titers of SARS-CoV-2-specific serum IgA were correlated with severe acute respiratory distress syndrome. Interestingly, some health care workers with negative SARS-CoV-2-specific serum antibody titers showed SARS-CoV-2-specific IgA in mucosal fluids with virus-neutralizing capacity in some cases. SARS-CoV-2-specific IgA titers in nasal fluids were inversely correlated with age. CONCLUSIONS Systemic antibody production against SARS-CoV-2 develops mainly in patients with severe COVID-19, with very high IgA titers seen in patients with severe acute respiratory distress syndrome, whereas mild disease may be associated with transient production of SARS-CoV-2-specific antibodies but may stimulate mucosal SARS-CoV-2-specific IgA secretion.
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Hofmaenner DA, Wendel Garcia PD, Duvnjak B, Chakrakodi B, Maier JD, Huber M, Huder J, Wolfensberger A, Schreiber PW, Schuepbach RA, Zinkernagel AS, Buehler PK, Brugger SD. Bacterial but no SARS-CoV-2 contamination after terminal disinfection of tertiary care intensive care units treating COVID-19 patients. Antimicrob Resist Infect Control 2021; 10:11. [PMID: 33436105 PMCID: PMC7802978 DOI: 10.1186/s13756-021-00885-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 01/05/2021] [Indexed: 01/08/2023] Open
Abstract
Background In intensive care units (ICUs) treating patients with Coronavirus disease 2019 (COVID-19) invasive ventilation poses a high risk for aerosol and droplet formation. Surface contamination of severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) or bacteria can result in nosocomial transmission.
Methods Two tertiary care COVID-19 intensive care units treating 53 patients for 870 patient days were sampled after terminal cleaning and preparation for regular use to treat non-COVID-19 patients. Results A total of 176 swabs were sampled of defined locations covering both ICUs. No SARS-CoV-2 ribonucleic acid (RNA) was detected. Gram-negative bacterial contamination was mainly linked to sinks and siphons. Skin flora was isolated from most swabbed areas and Enterococcus faecium was detected on two keyboards. Conclusions After basic cleaning with standard disinfection measures no remaining SARS-CoV-2 RNA was detected. Bacterial contamination was low and mainly localised in sinks and siphons.
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Maccio U, Zinkernagel AS, Shambat SM, Zeng X, Cathomas G, Ruschitzka F, Schuepbach RA, Moch H, Varga Z. SARS-CoV-2 leads to a small vessel endotheliitis in the heart. EBioMedicine 2021; 63:103182. [PMID: 33422990 PMCID: PMC7808909 DOI: 10.1016/j.ebiom.2020.103182] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND SARS-CoV-2 infection (COVID-19 disease) can induce systemic vascular involvement contributing to morbidity and mortality. SARS-CoV-2 targets epithelial and endothelial cells through the ACE2 receptor. The anatomical involvement of the coronary tree is not explored yet. METHODS Cardiac autopsy tissue of the entire coronary tree (main coronary arteries, epicardial arterioles/venules, epicardial capillaries) and epicardial nerves were analyzed in COVID-19 patients (n = 6). All anatomical regions were immunohistochemically tested for ACE2, TMPRSS2, CD147, CD45, CD3, CD4, CD8, CD68 and IL-6. COVID-19 negative patients with cardiovascular disease (n = 3) and influenza A (n = 6) served as controls. FINDINGS COVID-19 positive patients showed strong ACE2 / TMPRSS2 expression in capillaries and less in arterioles/venules. The main coronary arteries were virtually devoid of ACE2 receptor and had only mild intimal inflammation. Epicardial capillaries had a prominent lympho-monocytic endotheliitis, which was less pronounced in arterioles/venules. The lymphocytic-monocytic infiltrate strongly expressed CD4, CD45, CD68. Peri/epicardial nerves had strong ACE2 expression and lympho-monocytic inflammation. COVID-19 negative patients showed minimal vascular ACE2 expression and lacked endotheliitis or inflammatory reaction. INTERPRETATION ACE2 / TMPRSS2 expression and lymphomonocytic inflammation in COVID-19 disease increases crescentically towards the small vessels suggesting that COVID-19-induced endotheliitis is a small vessel vasculitis not involving the main coronaries. The inflammatory neuropathy of epicardial nerves in COVID-19 disease provides further evidence of an angio- and neurotrophic affinity of SARS-COV2 and might potentially contribute to the understanding of the high prevalence of cardiac complications such as myocardial injury and arrhythmias in COVID-19. FUNDING No external funding was necessary for this study.
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Huemer M, Mairpady Shambat S, Brugger SD, Zinkernagel AS. Antibiotic resistance and persistence-Implications for human health and treatment perspectives. EMBO Rep 2020; 21:e51034. [PMID: 33400359 PMCID: PMC7726816 DOI: 10.15252/embr.202051034] [Citation(s) in RCA: 187] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/13/2020] [Accepted: 11/02/2020] [Indexed: 12/24/2022] Open
Abstract
Antimicrobial resistance (AMR) and persistence are associated with an elevated risk of treatment failure and relapsing infections. They are thus important drivers of increased morbidity and mortality rates resulting in growing healthcare costs. Antibiotic resistance is readily identifiable with standard microbiological assays, and the threat imposed by antibiotic resistance has been well recognized. Measures aiming to reduce resistance development and spreading of resistant bacteria are being enforced. However, the phenomenon of bacteria surviving antibiotic exposure despite being fully susceptible, so-called antibiotic persistence, is still largely underestimated. In contrast to antibiotic resistance, antibiotic persistence is difficult to measure and therefore often missed, potentially leading to treatment failures. In this review, we focus on bacterial mechanisms allowing evasion of antibiotic killing and discuss their implications on human health. We describe the relationship between antibiotic persistence and bacterial heterogeneity and discuss recent studies that link bacterial persistence and tolerance with the evolution of antibiotic resistance. Finally, we review persister detection methods, novel strategies aiming at eradicating bacterial persisters and the latest advances in the development of new antibiotics.
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Burkhard-Koren NM, Haberecker M, Maccio U, Ruschitzka F, Schuepbach RA, Zinkernagel AS, Hardmeier T, Varga Z, Moch H. Higher prevalence of pulmonary macrothrombi in SARS-CoV-2 than in influenza A: autopsy results from 'Spanish flu' 1918/1919 in Switzerland to Coronavirus disease 2019. JOURNAL OF PATHOLOGY CLINICAL RESEARCH 2020; 7:135-143. [PMID: 33185036 PMCID: PMC7869934 DOI: 10.1002/cjp2.189] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/01/2020] [Accepted: 10/05/2020] [Indexed: 12/21/2022]
Abstract
Similar to the influenza A pandemic in 1918/1919, the new Coronavirus disease 2019 (COVID‐19) has spread globally. The causes of death in COVID‐19 are frequently compared to a seasonal influenza outbreak. Complete COVID‐19 autopsy studies were almost non‐existent in the first months of the outbreak and are still rare with respect to the number of deaths. It has been recently reported that capillary microthrombi are significantly more prevalent in patients with COVID‐19 than in patients with influenza A. To date, the contribution of macrothrombi, i.e. visible thrombi in pulmonary arteries, to the death of patients with influenza A in comparison to COVID‐19 remains unaddressed. Here, we report autopsy findings in 411 patients who died from the ‘Spanish’ influenza A pandemic between May 1918 and April 1919 at the University Hospital Zurich, Switzerland. We compare these results with influenza A autopsies from 2009 to 2020, other influenza A autopsy series and all COVID‐19 autopsies published to date. No descriptions of any macroscopic thromboembolic events were mentioned in influenza A autopsy reports. In 75 published COVID‐19 autopsies, pulmonary artery thrombosis/embolism was reported in 36%. The direct comparison of macroscopic autopsy findings suggests a significantly greater degree of grossly visible pulmonary macrothrombi in patients with COVID‐19 in comparison to influenza A autopsies even though most patients received empiric thromboprophylaxis. This is consistent with the concept of a SARS‐related de novo coagulopathy with generalised in situ clot formation, which could explain the high incidence of pulmonary thrombosis/embolism with or without underlying deep vein thrombosis and in the absence of a history of venous thromboembolic events.
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Bär J, Boumasmoud M, Kouyos RD, Zinkernagel AS, Vulin C. Efficient microbial colony growth dynamics quantification with ColTapp, an automated image analysis application. Sci Rep 2020; 10:16084. [PMID: 32999342 PMCID: PMC7528005 DOI: 10.1038/s41598-020-72979-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/08/2020] [Indexed: 12/14/2022] Open
Abstract
Populations of genetically identical bacteria are phenotypically heterogeneous, giving rise to population functionalities that would not be possible in homogeneous populations. For instance, a proportion of non-dividing bacteria could persist through antibiotic challenges and secure population survival. This heterogeneity can be studied in complex environmental or clinical samples by spreading the bacteria on agar plates and monitoring time to growth resumption in order to infer their metabolic state distribution. We present ColTapp, the Colony Time-lapse application for bacterial colony growth quantification. Its intuitive graphical user interface allows users to analyze time-lapse images of agar plates to monitor size, color and morphology of colonies. Additionally, images at isolated timepoints can be used to estimate lag time. Using ColTapp, we analyze a dataset of Staphylococcus aureus time-lapse images including populations with heterogeneous lag time. Colonies on dense plates reach saturation early, leading to overestimation of lag time from isolated images. We show that this bias can be corrected by taking into account the area available to each colony on the plate. We envision that in clinical settings, improved analysis of colony growth dynamics may help treatment decisions oriented towards personalized antibiotic therapies.
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Schweizer TA, Shambat SM, Haunreiter VD, Mestres CA, Weber A, Maisano F, Zinkernagel AS, Hasse B. Polyester Vascular Graft Material and Risk for Intracavitary Thoracic Vascular Graft Infection 1. Emerg Infect Dis 2020; 26:2448-2452. [PMID: 32946737 PMCID: PMC7510746 DOI: 10.3201/eid2610.191711] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Prosthetic vascular graft infections of the thoracic aorta are rare but can be fatal. Our comparison of collagen- and gelatin-coated grafts showed that collagen-coated grafts were associated with increased biofilm formation and bacterial adherence in vitro and with higher rates of perioperative vascular graft infections in vivo.
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Andronic O, Achermann Y, Jentzsch T, Bearth F, Schweizer A, Wieser K, Fucentese SF, Rahm S, Zinkernagel AS, Zingg PO. Factors affecting outcome in the treatment of streptococcal periprosthetic joint infections: results from a single-centre retrospective cohort study. INTERNATIONAL ORTHOPAEDICS 2020; 45:57-63. [PMID: 32856092 PMCID: PMC7801309 DOI: 10.1007/s00264-020-04722-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/07/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To report and analyse factors affecting the outcome of streptococcal periprosthetic joint infections (PJIs). METHODS A retrospective analysis of consecutive streptococcal PJIs was performed. Musculoskeletal Infection Society 2013 criteria were used. Outcome was compared with a prospective PJI cohort from the same institution. RESULTS The most common isolated streptococcal species was Streptococcus dysgalactiae (9/22, 41%) among 22 patients included. Surgical treatment consisted of DAIR (debridement, antibiotics, irrigation and retention) in 12 (55%), one-stage revision arthroplasty in one (4%), two-stage revision arthroplasty in eight (37%) and implant removal in one (4%) patient. An infection free-outcome was achieved in 15 cases (68%), whilst seven (32%) patients failed initial revision and relapsed with the same pathogen, from which six were treated with DAIR and one with one-stage revision arthroplasty. No failures were observed in patients who received a two-stage revision. Failure rates did not differ in the cases treated with rifampin (1/5) from those without 6/17 (p = 0.55). There was no correlation between the length of antibiotic treatment and relapse (p = 0.723). In all failures, a persistent distant infection focus was identified at the time of relapse. Compared with our prospective PJI cohort, relapse rates were significantly higher 32% vs 12% (p < 0.05). CONCLUSION No correlation with the use of rifampin or length of antibiotic treatment was found. No failures were observed in patients who received a two-stage revision, which may be the surgical treatment of choice. A distant persisting infection focus could be the reason for PJI relapse with recurrent hematogenous seeding in the joint.
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Amodio E, Kuster SP, Garzoni C, Zinkernagel AS, Sax H, Wolfensberger A. Disinfecting noncritical medical equipment-Effectiveness of hydrogen peroxide dry mist as an adjunctive method. Am J Infect Control 2020; 48:897-902. [PMID: 32464292 DOI: 10.1016/j.ajic.2020.05.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND Manual disinfection of medical devices is prone to failure. Disinfection by aerosolized hydrogen peroxide might be a promising adjunctive method. We aimed to assess effectiveness of dry mist of hydrogen peroxide (HPDM) on noncritical medical equipment. METHODS One cycle of HPDM was applied on a convenience sample of 16 different types of "ready to use" noncritical medical devices in a closed, but nonsealed room. Of every object, 2 adjacent areas with assumed similar bacterial burden were swabbed before and after HPDM deployment, respectively. After culturing, colony forming units (CFU) were counted, and bacterial burden per cm2 calculated. RESULTS Of 160 objects included in the study, 36 (23%) showed a CFU-count of zero both before and after HPDM use. A decrease from a median of 0.14 CFU/cm2 (range: 0.00-125.00/cm2) to a median of 0.00 CFU/cm2 (range: 0.00-4.00/cm2) (P < .001) was observed. The bacterial burden was reduced by more than 90% in 45% (95% CI: 37-53) of objects. No pathogenic bacteria were identified. DISCUSSION HPDM reduced bacterial burden on noncritical medical items. Since cleanliness of the included "ready to use" objects was high and no pathogens were found before nebulization, the HPDM device did not increase patient safety in this setting. CONCLUSION HPDM nebulization can be a useful nonmanual adjunctive disinfection method in high-risk settings.
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Malerba M, Louis S, Cuvellier S, Shambat SM, Hua C, Gomart C, Fouet A, Ortonne N, Decousser JW, Zinkernagel AS, Mathieu JR, Peyssonnaux C. Epidermal hepcidin is required for neutrophil response to bacterial infection. J Clin Invest 2020; 130:329-334. [PMID: 31600168 PMCID: PMC6934188 DOI: 10.1172/jci126645] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 10/02/2019] [Indexed: 01/21/2023] Open
Abstract
Novel approaches for adjunctive therapy are urgently needed for complicated infections and patients with compromised immunity. Necrotizing fasciitis (NF) is a destructive skin and soft tissue infection. Despite treatment with systemic antibiotics and radical debridement of necrotic tissue, lethality remains high. The key iron regulatory hormone hepcidin was originally identified as a cationic antimicrobial peptide (AMP), but its putative expression and role in the skin, a major site of AMP production, have never been investigated. We report here that hepcidin production is induced in the skin of patients with group A Streptococcus (GAS) NF. In a GAS-induced NF model, mice lacking hepcidin in keratinocytes failed to restrict systemic spread of infection from an initial tissue focus. Unexpectedly, this effect was due to its ability to promote production of the CXCL1 chemokine by keratinocytes, resulting in neutrophil recruitment. Unlike CXCL1, hepcidin is resistant to degradation by major GAS proteases and could therefore serve as a reservoir to maintain steady-state levels of CXCL1 in infected tissue. Finally, injection of synthetic hepcidin at the site of infection can limit or completely prevent systemic spread of GAS infection, suggesting that hepcidin agonists could have a therapeutic role in NF.
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Häffner N, Bär J, Dengler Haunreiter V, Mairpady Shambat S, Seidl K, Crosby HA, Horswill AR, Zinkernagel AS. Intracellular Environment and agr System Affect Colony Size Heterogeneity of Staphylococcus aureus. Front Microbiol 2020; 11:1415. [PMID: 32695082 PMCID: PMC7339952 DOI: 10.3389/fmicb.2020.01415] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 06/02/2020] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus causes chronic and relapsing infections, which may be difficult to treat. So-called small colony variants (SCVs) have been associated with chronic infections and their occurrence has been shown to increase under antibiotic pressure, low pH and intracellular localization. In clinics, S. aureus isolated from invasive infections often show a dysfunction in the accessory gene regulator (agr), a major virulence regulatory system in S. aureus. To assess whether intracellular environment and agr function influence SCV formation, an infection model was established using lung epithelial cells and skin fibroblasts. This allowed analyzing intracellular survival and localization of a panel of S. aureus wild type strains and their isogenic agr knock out mutants as well as a natural dysfunctional agr strain by confocal laser scanning microscopy (CLSM). Furthermore, bacterial colonies were quantified after 1, 3, and 5 days of intracellular survival by time-lapse analysis to determine kinetics of colony appearance and SCV formation. Here, we show that S. aureus strains with an agr knock out predominantly resided in a neutral environment, whereas wild type strains and an agr complemented strain resided in an acidic environment. S. aureus agr mutants derived from an intracellular environment showed a higher percentage of SCVs as compared to their corresponding wild type strains. Neutralizing acidic phagolysosomes with chloroquine resulted in a significant reduction of SCVs in S. aureus wild type strain 6850, but not in its agr mutant indicating a pH dependent formation of SCVs in the wild type strain. The in-depth understanding of the interplay between intracellular persistence, agr function and pH should help to identify new therapeutic options facilitating the treatment of chronic S. aureus infections in the future.
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Manka R, Karolyi M, Polacin M, Holy EW, Nemeth J, Steiger P, Schuepbach RA, Zinkernagel AS, Alkadhi H, Mehra MR, Ruschitzka F. Myocardial edema in COVID-19 on cardiac MRI. J Heart Lung Transplant 2020; 39:730-732. [PMID: 32650881 PMCID: PMC7834291 DOI: 10.1016/j.healun.2020.04.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/28/2022] Open
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Varga Z, Flammer AJ, Steiger P, Haberecker M, Andermatt R, Zinkernagel AS, Mehra MR, Schuepbach RA, Ruschitzka F, Moch H. Endothelial cell infection and endotheliitis in COVID-19. Lancet 2020; 395:1417-1418. [PMID: 32325026 PMCID: PMC7172722 DOI: 10.1016/s0140-6736(20)30937-5] [Citation(s) in RCA: 4297] [Impact Index Per Article: 1074.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 04/16/2020] [Indexed: 02/06/2023]
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