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Jebbawi F, Bellanger AP, Lunström-Stadelmann B, Rufener R, Dosch M, Goepfert C, Gottstein B, Millon L, Grandgirard D, Leib SL, Beldi G, Wang J. Innate and adaptive immune responses following PD-L1 blockade in treating chronic murine alveolar echinococcosis. Parasite Immunol 2021; 43:e12834. [PMID: 33754355 DOI: 10.1111/pim.12834] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 02/10/2021] [Accepted: 03/17/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) immune checkpoint blockade are efficacious in certain cancer therapies. OBJECTIVES The present study aimed to provide a picture about the development of innate and adaptive immune responses upon PD-L1 blockade in treating chronic murine AE. METHODS Immune treatment started at 6 weeks post-E. multilocularis infection, and was maintained for 8 weeks with twice per week anti-PD-L1 administration (intraperitoneal). The study included an outgroup-control with mice perorally medicated with albendazole 5 d/wk, and another one with both treatments combined. Assessment of treatment efficacy was based on determining parasite weight, innate and adaptive immune cell profiles, histopathology and liver tissue cytokine levels. RESULTS/CONCLUSIONS Findings showed that the parasite load was significantly reduced in response to PD-L1 blockade, and this blockade (a) contributed to T-cell activity by increasing CD4+ /CD8+ effector T cells, and decreasing Tregs; (b) had the capacity to restore DCs and Kupffer cells/Macrophages; (c) suppressed NKT and NK cells; and thus (d) lead to an improved control of E. multilocularis infection in mice. This study suggests that the PD-L1 pathway plays an important role by regulating adaptive and innate immune cells against E. multilocularis infection, with significant modulation of tissue inflammation.
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Valente LG, Pitton M, Fürholz M, Oberhaensli S, Bruggmann R, Leib SL, Jakob SM, Resch G, Que YA, Cameron DR. Isolation and characterization of bacteriophages from the human skin microbiome that infect Staphylococcus epidermidis. FEMS MICROBES 2021; 2:xtab003. [PMID: 37334235 PMCID: PMC10117716 DOI: 10.1093/femsmc/xtab003] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/26/2021] [Indexed: 07/20/2023] Open
Abstract
Phage therapy might be a useful approach for the treatment of nosocomial infections; however, only few lytic phages suitable for this application are available for the opportunistic pathogen, Staphylococcus epidermidis. In the current study, we developed an efficient method to isolate bacteriophages present within the human skin microbiome, by using niche-specific S. epidermidis as the host for phage propagation. Staphylococcus epidermidis was identified on the forehead of 92% of human subjects tested. These isolates were then used to propagate phages present in the same skin sample. Plaques were observable on bacterial lawns in 46% of the cases where S. epidermidis was isolated. A total of eight phage genomes were genetically characterized, including the previously described phage 456. A total of six phage sequences were unique, and spanned each of the major staphylococcal phage families; Siphoviridae (n = 3), Podoviridae (n = 1) and Myoviridae (n = 2). One of the myoviruses (vB_SepM_BE06) was identified on the skin of three different humans. Comparative analysis identified novel genes including a putative N-acetylmuramoyl-L-alanine amidase gene. The host-range of each unique phage was characterized using a panel of diverse staphylococcal strains (n = 78). None of the newly isolated phages infected more than 52% of the S. epidermidis strains tested (n = 44), and non-S. epidermidis strains where rarely infected, highlighting the narrow host-range of the phages. One of the phages (vB_SepM_BE04) was capable of killing staphylococcal cells within biofilms formed on polyurethane catheters. Uncovering a richer diversity of available phages will likely improve our understanding of S. epidermidis-phage interactions, which will be important for future therapy.
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Goncalves Cabecinhas AR, Roloff T, Stange M, Bertelli C, Huber M, Ramette A, Chen C, Nadeau S, Gerth Y, Yerly S, Opota O, Pillonel T, Schuster T, Metzger CMJA, Sieber J, Bel M, Wohlwend N, Baumann C, Koch MC, Bittel P, Leuzinger K, Brunner M, Suter-Riniker F, Berlinger L, Søgaard KK, Beckmann C, Noppen C, Redondo M, Steffen I, Seth-Smith HMB, Mari A, Lienhard R, Risch M, Nolte O, Eckerle I, Martinetti Lucchini G, Hodcroft EB, Neher RA, Stadler T, Hirsch HH, Leib SL, Risch L, Kaiser L, Trkola A, Greub G, Egli A. SARS-CoV-2 N501Y Introductions and Transmissions in Switzerland from Beginning of October 2020 to February 2021-Implementation of Swiss-Wide Diagnostic Screening and Whole Genome Sequencing. Microorganisms 2021; 9:677. [PMID: 33806013 PMCID: PMC8064472 DOI: 10.3390/microorganisms9040677] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/10/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022] Open
Abstract
The rapid spread of the SARS-CoV-2 lineages B.1.1.7 (N501Y.V1) throughout the UK, B.1.351 (N501Y.V2) in South Africa, and P.1 (B.1.1.28.1; N501Y.V3) in Brazil has led to the definition of variants of concern (VoCs) and recommendations for lineage specific surveillance. In Switzerland, during the last weeks of December 2020, we established a nationwide screening protocol across multiple laboratories, focusing first on epidemiological and microbiological definitions. In January 2021, we validated and implemented an N501Y-specific PCR to rapidly screen for VoCs, which are then confirmed using amplicon sequencing or whole genome sequencing (WGS). A total of 13,387 VoCs have been identified since the detection of the first Swiss case in October 2020, with 4194 being B.1.1.7, 172 B.1.351, and 7 P.1. The remaining 9014 cases of VoCs have been described without further lineage specification. Overall, all diagnostic centers reported a rapid increase of the percentage of detected VOCs, with a range of 6 to 46% between 25 to 31 of January 2021 increasing towards 41 to 82% between 22 to 28 of February. A total of 739 N501Y positive genomes were analysed and show a broad range of introduction events to Switzerland. In this paper, we describe the nationwide coordination and implementation process across laboratories, public health institutions, and researchers, the first results of our N501Y-specific variant screening, and the phylogenetic analysis of all available WGS data in Switzerland, that together identified the early introduction events and subsequent community spreading of the VoCs.
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Engelter ST, Traenka C, Gensicke H, Schaedelin SA, Luft AR, Simonetti BG, Fischer U, Michel P, Sirimarco G, Kägi G, Vehoff J, Nedeltchev K, Kahles T, Kellert L, Rosenbaum S, von Rennenberg R, Sztajzel R, Leib SL, Jung S, Gralla J, Bruni N, Seiffge D, Feil K, Polymeris AA, Steiner L, Hamann J, Bonati LH, Brehm A, De Marchis GM, Peters N, Stippich C, Nolte CH, Christensen H, Wegener S, Psychogios MN, Arnold M, Lyrer P. Aspirin versus anticoagulation in cervical artery dissection (TREAT-CAD): an open-label, randomised, non-inferiority trial. Lancet Neurol 2021; 20:341-350. [PMID: 33765420 DOI: 10.1016/s1474-4422(21)00044-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/22/2021] [Accepted: 02/02/2021] [Indexed: 01/13/2023]
Abstract
BACKGROUND Cervical artery dissection is a major cause of stroke in young people (aged <50 years). Historically, clinicians have preferred using oral anticoagulation with vitamin K antagonists for patients with cervical artery dissection, although some current guidelines-based on available evidence from mostly observational studies-suggest using aspirin. If proven to be non-inferior to vitamin K antagonists, aspirin might be preferable, due to its ease of use and lower cost. We aimed to test the non-inferiority of aspirin to vitamin K antagonists in patients with cervical artery dissection. METHODS We did a multicentre, randomised, open-label, non-inferiority trial in ten stroke centres across Switzerland, Germany, and Denmark. We randomly assigned (1:1) patients aged older than 18 years who had symptomatic, MRI-verified, cervical artery dissection within 2 weeks before enrolment, to receive either aspirin 300 mg once daily or a vitamin K antagonist (phenprocoumon, acenocoumarol, or warfarin; target international normalised ratio [INR] 2·0-3·0) for 90 days. Randomisation was computer-generated using an interactive web response system, with stratification according to participating site. Independent imaging core laboratory adjudicators were masked to treatment allocation, but investigators, patients, and clinical event adjudicators were aware of treatment allocation. The primary endpoint was a composite of clinical outcomes (stroke, major haemorrhage, or death) and MRI outcomes (new ischaemic or haemorrhagic brain lesions) in the per-protocol population, assessed at 14 days (clinical and MRI outcomes) and 90 days (clinical outcomes only) after commencing treatment. Non-inferiority of aspirin would be shown if the upper limit of the two-sided 95% CI of the absolute risk difference between groups was less than 12% (non-inferiority margin). This trial is registered with ClinicalTrials.gov, NCT02046460. FINDINGS Between Sept 11, 2013, and Dec 21, 2018, we enrolled 194 patients; 100 (52%) were assigned to the aspirin group and 94 (48%) were assigned to the vitamin K antagonist group. The per-protocol population included 173 patients; 91 (53%) in the aspirin group and 82 (47%) in the vitamin K antagonist group. The primary endpoint occurred in 21 (23%) of 91 patients in the aspirin group and in 12 (15%) of 82 patients in the vitamin K antagonist group (absolute difference 8% [95% CI -4 to 21], non-inferiority p=0·55). Thus, non-inferiority of aspirin was not shown. Seven patients (8%) in the aspirin group and none in the vitamin K antagonist group had ischaemic strokes. One patient (1%) in the vitamin K antagonist group and none in the aspirin group had major extracranial haemorrhage. There were no deaths. Subclinical MRI outcomes were recorded in 14 patients (15%) in the aspirin group and in 11 patients (13%) in the vitamin K antagonist group. There were 19 adverse events in the aspirin group, and 26 in the vitamin K antagonist group. INTERPRETATION Our findings did not show that aspirin was non-inferior to vitamin K antagonists in the treatment of cervical artery dissection. FUNDING Swiss National Science Foundation, Swiss Heart Foundation, Stroke Funds Basel, University Hospital Basel, University of Basel, Academic Society Basel.
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Brigger D, Horn MP, Pennington LF, Powell AE, Siegrist D, Weber B, Engler O, Piezzi V, Damonti L, Iseli P, Hauser C, Froehlich TK, Villiger PM, Bachmann MF, Leib SL, Bittel P, Fiedler M, Largiadèr CR, Marschall J, Stalder H, Kim PS, Jardetzky TS, Eggel A, Nagler M. Accuracy of serological testing for SARS-CoV-2 antibodies: First results of a large mixed-method evaluation study. Allergy 2021; 76:853-865. [PMID: 32997812 PMCID: PMC7537154 DOI: 10.1111/all.14608] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/11/2020] [Accepted: 09/13/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Serological immunoassays that can identify protective immunity against SARS-CoV-2 are needed to adapt quarantine measures, assess vaccination responses, and evaluate donor plasma. To date, however, the utility of such immunoassays remains unclear. In a mixed-design evaluation study, we compared the diagnostic accuracy of serological immunoassays that are based on various SARS-CoV-2 proteins and assessed the neutralizing activity of antibodies in patient sera. METHODS Consecutive patients admitted with confirmed SARS-CoV-2 infection were prospectively followed alongside medical staff and biobank samples from winter 2018/2019. An in-house enzyme-linked immunosorbent assay utilizing recombinant receptor-binding domain (RBD) of the SARS-CoV-2 spike protein was developed and compared to three commercially available enzyme-linked immunosorbent assays (ELISAs) targeting the nucleoprotein (N), the S1 domain of the spike protein (S1), and a lateral flow immunoassay (LFI) based on full-length spike protein. Neutralization assays with live SARS-CoV-2 were performed. RESULTS One thousand four hundred and seventy-seven individuals were included comprising 112 SARS-CoV-2 positives (defined as a positive real-time PCR result; prevalence 7.6%). IgG seroconversion occurred between day 0 and day 21. While the ELISAs showed sensitivities of 88.4% for RBD, 89.3% for S1, and 72.9% for N protein, the specificity was above 94% for all tests. Out of 54 SARS-CoV-2 positive individuals, 96.3% showed full neutralization of live SARS-CoV-2 at serum dilutions ≥ 1:16, while none of the 6 SARS-CoV-2-negative sera revealed neutralizing activity. CONCLUSIONS ELISAs targeting RBD and S1 protein of SARS-CoV-2 are promising immunoassays which shall be further evaluated in studies verifying diagnostic accuracy and protective immunity against SARS-CoV-2.
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Prazak J, Valente L, Iten M, Federer L, Grandgirard D, Soto S, Resch G, Leib SL, Jakob SM, Haenggi M, Cameron DR, Que YA. Benefits of aerosolized phages for the treatment of pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA): an experimental study in rats. J Infect Dis 2021; 225:1452-1459. [PMID: 33668071 PMCID: PMC9016458 DOI: 10.1093/infdis/jiab112] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 02/23/2021] [Indexed: 12/14/2022] Open
Abstract
Background The optimal method for delivering phages in the context of ventilator-associated pneumonia (VAP) is unknown. In the current study, we assessed the utility of aerosolized phages (aerophages) for experimental methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. Methods Rats were ventilated for 4 hours before induction of pneumonia. Animals received one of the following: (1) aerophages; (2) intravenous (IV) phages; (3) a combination of IV and aerophages; (4) IV linezolid; or (5) a combination of IV linezolid and aerophages. Phages were administered at 2, 12, 24, 48, and 72 hours, and linezolid was administered at 2, 12, 24, 36, 48, 60, and 72 hours. The primary outcome was survival at 96 hours. Secondary outcomes were bacterial and phage counts in tissues and histopathological scoring of the lungs. Results Aerophages and IV phages each rescued 50% of animals from severe MRSA pneumonia (P < .01 compared with placebo controls). The combination of aerophages and IV phages rescued 91% of animals, which was higher than either monotherapy (P < .05). Standard-of-care antibiotic linezolid rescued 38% of animals. However, linezolid and aerophages did not synergize in this setting (55% survival). Conclusions Aerosolized phage therapy showed potential for the treatment of MRSA pneumonia in an experimental animal model and warrants further investigation for application in humans.
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Grüter BE, Wanderer S, Strange F, Boillat G, Täschler D, Rey J, Croci DM, Grandgirard D, Leib SL, von Gunten M, Di Santo S, Widmer HR, Remonda L, Andereggen L, Nevzati E, Coluccia D, Fandino J, Marbacher S. Patterns of Neointima Formation After Coil or Stent Treatment in a Rat Saccular Sidewall Aneurysm Model. Stroke 2021; 52:1043-1052. [PMID: 33504186 DOI: 10.1161/strokeaha.120.032255] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Endovascular aneurysm treatment relies on a biological process, including cell migration for thrombus organization and growth of a neointima. To better understand aneurysm healing, our study explores the origin of neointima-forming and thrombus-organizing cells in a rat saccular sidewall aneurysm model. METHODS Saccular aneurysms were transplanted onto the abdominal aorta of male Lewis rats and endovascularly treated with coils (n=28) or stents (n=26). In 34 cases, GFP+ (green fluorescent protein)-expressing vital aneurysms were sutured on wild-type rats, and in 23 cases, decellularized wild-type aneurysms were sutured on GFP+ rats. Follow-up at 3, 7, 14, 21, and 28 days evaluated aneurysms by fluorescence angiography, macroscopic inspection, and microscopy for healing and inflammation status. Furthermore, the origin of cells was tracked with fluorescence histology. RESULTS In animals with successful functional healing, histological studies showed a gradually advancing thrombus organization over time characterized by progressively growing neointima from the periphery of the aneurysm toward the center. Cell counts revealed similar distributions of GFP+ cells for coil or stent treatment in the aneurysm wall (54.4% versus 48.7%) and inside the thrombus (20.5% versus 20.2%) but significantly more GFP+ cells in the neointima of coiled (27.2 %) than stented aneurysms (10.4%; P=0.008). CONCLUSIONS Neointima formation and thrombus organization are concurrent processes during aneurysm healing. Thrombus-organizing cells originate predominantly in the parent artery. Neointima formation relies more on cell migration from the aneurysm wall in coiled aneurysms but receives greater contributions from cells originating in the parent artery in stent-treated aneurysms. Cell migration, which allows for a continuous endothelial lining along the parent artery's lumen, may be a prerequisite for complete aneurysm healing after endovascular therapy. In terms of translation into clinical practice, these findings may explain the variability in achieving complete aneurysm healing after coil treatment and the improved healing rate in stent-assisted coiling.
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Rosser C, Sager F, Leib SL. Six Recommendations to Build Legitimacy for Translational Research Organizations. Front Med (Lausanne) 2020; 7:586177. [PMID: 33364246 PMCID: PMC7755134 DOI: 10.3389/fmed.2020.586177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/15/2020] [Indexed: 11/22/2022] Open
Abstract
Translational research organizations (TROs) face specific challenges to secure resilience and longevity. This perspective article provides the rationale for six hands-on recommendations for the management of legitimacy building in TROs.
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Pan SD, Grandgirard D, Leib SL. Adjuvant Cannabinoid Receptor Type 2 Agonist Modulates the Polarization of Microglia Towards a Non-Inflammatory Phenotype in Experimental Pneumococcal Meningitis. Front Cell Infect Microbiol 2020; 10:588195. [PMID: 33251159 PMCID: PMC7674855 DOI: 10.3389/fcimb.2020.588195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/14/2020] [Indexed: 12/26/2022] Open
Abstract
Background Microglia initiates and sustains the inflammatory reaction that drives the pathogenesis of pneumococcal meningitis. The expression of the G-protein cannabinoid receptor type 2 (CB2) in the brain is low, but is upregulated in glial cells during infection. Its activation down-regulates pro-inflammatory processes, driving microglia towards an anti-inflammatory phenotype. CB2 agonists are therefore therapeutic candidates in inflammatory conditions like pneumococcal meningitis. We evaluated the effects of JWH-133, a specific CB2 agonist on microglial cells, inflammation, and damage driven by S. pneumoniae in vitro and in experimental pneumococcal meningitis. Materials/methods Primary mixed glial cultures were stimulated with live or heat-inactivated S. pneumoniae, or lipopolysaccharide and treated with JWH-133 or vehicle. Nitric oxide and cytokines levels were measured in the supernatant. In vivo, pneumococcal meningitis was induced by intracisternal injection of live S. pneumoniae in 11 days old Wistar rats. Animals were treated with antibiotics (Ceftriaxone, 100 mg/kg, s.c. bid) and JWH-133 (1 mg/kg, i.p. daily) or vehicle (10% Ethanol in saline, 100 µl/25g body weight) at 18 h after infection. Brains were harvested at 24 and 42 h post infection (hpi) for histological assessment of hippocampal apoptosis and cortical damage and determination of cyto/chemokines in tissue homogenates. Microglia were characterized using Iba-1 immunostaining. Inflammation in brain homogenates was determined using membrane-based antibody arrays. Results In vitro, nitric oxide and cytokines levels were significantly lowered by JWH-133 treatment. In vivo, clinical parameters were not affected by the treatment. JWH-133 significantly lowered microglia activation assessed by quantification of cell process length and endpoints per microglia. Animals treated with JWH-133 demonstrated significantly lower parenchymal levels of chemokines (CINC-1, CINC-2α/β, and MIP-3α), TIMP-1, and IL-6 at 24 hpi, and CINC-1, MIP-1α, and IL-1α at 42 hpi. Quantitative analysis of brain damage did not reveal an effect of JWH-133. Conclusions JWH-133 attenuates microglial activation and downregulates the concentrations of pro-inflammatory mediators in pneumococcal infection in vitro and in vivo. However, we didn't observe a reduction in cortical or hippocampal injury. This data provides evidence that inhibition of microglia by adjuvant CB2 agonists therapy effectively downmodulates neuroinflammation but does not reduce brain damage in experimental pneumococcal meningitis.
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Zbinden FR, De Ste Croix M, Grandgirard D, Haigh RD, Vacca I, Zamudio R, Goodall ECA, Stephan R, Oggioni MR, Leib SL. Pathogenic Differences of Type 1 Restriction-Modification Allele Variants in Experimental Listeria monocytogenes Meningitis. Front Cell Infect Microbiol 2020; 10:590657. [PMID: 33194838 PMCID: PMC7662400 DOI: 10.3389/fcimb.2020.590657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 09/25/2020] [Indexed: 11/13/2022] Open
Abstract
Background: L. monocytogenes meningoencephalitis has a mortality rate of up to 50% and neurofunctional sequelae are common. Type I restriction-modification systems (RMS) are capable of adding methyl groups to the host genome. Some contain multiple sequence recognition (hsdS) genes that recombine, resulting in distinct DNA methylation patterns and patterns of gene expression. These phenotypic switches have been linked to virulence and have recently been discovered in multiple clonal complexes of L. monocytogenes. In the present study, we investigated the significant of RMS on L. monocytogenes virulence during the acute phase of experimental meningitis. Methods: L. monocytogenes strains containing RMS systems were identified, and purified clones enriched for single hsdS alleles were isolated. In vivo, 11-day old Wistar rats were infected with an inoculum containing (a) one of 4 single RMS allele variants (A, B, C, D) treated with amoxicillin (AMX 50 mg/kg/dosis, q8h), (b) a mixture of all 4 variants with or without AMX treatment, or (c) different mixtures of 2 RMS allele variants. At selected time points after infection, clinical and inflammatory parameters, bacterial titers and brain damage were determined. Changes in the relative frequency of the occurring RMS alleles in the inoculum and in CSF or cerebellum of infected animals were analyzed by capillary electrophoresis. Results: We have identified a phase variable RMS locus within L. monocytogenes CC4 and generated stocks that stably expressed each of the possible hsdS genes within that loci. Generation of these allele variants (A, B, C, D) allowed us to determine the methylation pattern associated with each hsdS through SMRT sequencing. In vivo infections with these single allele variants revealed differences in disease severity in that C induced the worst clinical outcome and more pronounced hippocampal apoptosis; D showed the most pronounced weight loss and the highest bacterial titer in the cerebellum. A caused the least severe disease. Conclusion: We identified that L. monocytogenes expressing hsdS (A) causes less damage than when other hsdS genes are expressed. While expression of hsdSC and D worsened the outcome in L. monocytogenes meningitis. We also demonstrate a competitive advantage of variants C and B over variant A in this model. Phenotypical switching may therefore represent a mechanism of virulence regulation during the acute phase of CNS infections with L. monocytogenes.
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Le ND, Muri L, Grandgirard D, Kuhle J, Leppert D, Leib SL. Evaluation of neurofilament light chain in the cerebrospinal fluid and blood as a biomarker for neuronal damage in experimental pneumococcal meningitis. J Neuroinflammation 2020; 17:293. [PMID: 33028339 PMCID: PMC7539528 DOI: 10.1186/s12974-020-01966-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/24/2020] [Indexed: 12/12/2022] Open
Abstract
Background Pneumococcal meningitis (PM) remains a global public health concern and affects all age groups. If acquired during infancy or childhood, permanent neurofunctional deficits including cognitive impairment, cerebral palsy, and secondary epilepsy are typical sequelae of neuronal injury. Determination of patients at risk for the development of brain injury and subsequent neurofunctional sequelae could help to identify patients for focused management. Neurofilament light chain (NfL) is an axonal cytoskeletal protein released upon neuronal injury into the cerebrospinal fluid (CSF) and blood. As little is known about the course of neurofilament release in the course of PM, we measured CSF and serum NfL levels longitudinally in experimental PM (ePM). Methods Eleven-day-old infant Wistar rats were infected intracisternally with Streptococcus pneumoniae and treated with ceftriaxone. At 18 and 42 h post-infection (hpi), the blood and CSF were sampled for NfL measurements by a single molecule array technology. Inflammatory cytokines and MMP-9 in CSF were quantified by magnetic bead multiplex assay (Luminex®) and by gel zymography, respectively. Results In ePM, CSF and serum NfL levels started to increase at 18 hpi and were 26- and 3.5-fold increased, respectively, compared to mock-infected animals at 42 hpi (p < 0.0001). CSF and serum NfL correlated at 18 hpi (p < 0.05, r = 0.4716) and 42 hpi (p < 0.0001, r = 0.8179). Both CSF and serum NfL at 42 hpi strongly correlated with CSF levels of IL-1β, TNF-α, and IL-6 and of MMP-9 depending on their individual kinetics. Conclusion Current results demonstrate that during the peak inflammatory phase of ePM, NfL levels in CSF and serum are the highest among CNS disease models studied so far. Given the strong correlation of CSF versus serum NfL, and its CNS-specific signal character, longitudinal measurements to monitor the course of PM could be performed based on blood sample tests, i.e., without the need of repetitive spinal taps. We conclude that NfL in the serum should be evaluated as a biomarker in PM.
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Muri L, Oberhänsli S, Buri M, Le ND, Grandgirard D, Bruggmann R, Müri RM, Leib SL. Repetitive transcranial magnetic stimulation activates glial cells and inhibits neurogenesis after pneumococcal meningitis. PLoS One 2020; 15:e0232863. [PMID: 32915781 PMCID: PMC7485822 DOI: 10.1371/journal.pone.0232863] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/21/2020] [Indexed: 11/19/2022] Open
Abstract
Pneumococcal meningitis (PM) causes damage to the hippocampus, a brain structure critically involved in learning and memory. Hippocampal injury-which compromises neurofunctional outcome-occurs as apoptosis of progenitor cells and immature neurons of the hippocampal dentate granule cell layer thereby impairing the regenerative capacity of the hippocampal stem cell niche. Repetitive transcranial magnetic stimulation (rTMS) harbours the potential to modulate the proliferative activity of this neuronal stem cell niche. In this study, specific rTMS protocols-namely continuous and intermittent theta burst stimulation (cTBS and iTBS)-were applied on infant rats microbiologically cured from PM by five days of antibiotic treatment. Following two days of exposure to TBS, differential gene expression was analysed by whole transcriptome analysis using RNAseq. cTBS provoked a prominent effect in inducing differential gene expression in the cortex and the hippocampus, whereas iTBS only affect gene expression in the cortex. TBS induced polarisation of microglia and astrocytes towards an inflammatory phenotype, while reducing neurogenesis, neuroplasticity and regeneration. cTBS was further found to induce the release of pro-inflammatory cytokines in vitro. We conclude that cTBS intensified neuroinflammation after PM, which translated into increased release of pro-inflammatory mediators thereby inhibiting neuroregeneration.
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Egli A, Battegay M, Büchler AC, Bühlmann P, Calandra T, Eckert P, Furrer H, Greub G, Jakob SM, Kaiser L, Leib SL, Marsch S, Meinshausen N, Pagani JL, Pugin J, Rätsch G, Schrenzel J, Schüpbach R, Siegemund M, Zamboni N, Zbinden R, Zinkernagel A, Borgwardt K. SPHN/PHRT: Forming a Swiss-Wide Infrastructure for Data-Driven Sepsis Research. Stud Health Technol Inform 2020; 270:1163-1167. [PMID: 32570564 DOI: 10.3233/shti200346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sepsis is a highly heterogenous syndrome with variable causes and outcomes. As part of the SPHN/PHRT funding program, we aim to build a highly interoperable, interconnected network for data collection, exchange and analysis of patients on intensive care units in order to predict sepsis onset and mortality earlier. All five University Hospitals, Universities, the Swiss Institute of Bioinformatics and ETH Zurich are involved in this multi-disciplinary project. With two prospective clinical observational studies, we test our infrastructure setup and improve the framework gradually and generate relevant data for research.
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Wasimuddin, Schlaeppi K, Ronchi F, Leib SL, Erb M, Ramette A. Evaluation of primer pairs for microbiome profiling from soils to humans within the One Health framework. Mol Ecol Resour 2020; 20:1558-1571. [PMID: 32599660 PMCID: PMC7693082 DOI: 10.1111/1755-0998.13215] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 06/06/2020] [Accepted: 06/16/2020] [Indexed: 12/15/2022]
Abstract
The 'One Health' framework emphasizes the ecological relationships between soil, plant, animal and human health. Microbiomes play important roles in these relationships, as they modify the health and performance of the different compartments and influence the transfer of energy, matter and chemicals between them. Standardized methods to characterize microbiomes along food chains are, however, currently lacking. To address this methodological gap, we evaluated the performance of DNA extraction kits and commonly recommended primer pairs targeting different hypervariable regions (V3-V4, V4, V5-V6, V5-V6-V7) of the 16S rRNA gene, on microbiome samples along a model food chain, including soils, maize roots, cattle rumen, and cattle and human faeces. We also included faeces from gnotobiotic mice colonized with defined bacterial taxa and mock communities to confirm the robustness of our molecular and bioinformatic approaches on these defined low microbial diversity samples. Based on Amplicon Sequence Variants, the primer pair 515F-806R led to the highest estimates of species richness and diversity in all sample types and offered maximum diversity coverage of reference databases in in silico primer analysis. The influence of the DNA extraction kits was negligible compared to the influence of the choice of primer pairs. Comparing microbiomes using 515F-806R revealed that soil and root samples have the highest estimates of species richness, while lowest richness was observed in human faeces. Primer pair choice directly influenced the estimation of community changes within and across compartments and may give rise to preferential detection of specific taxa. This work demonstrates why a standardized approach is necessary to analyse microbiomes within and between source compartments along food chains in the context of the One Health framework.
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Brigger D, Riether C, van Brummelen R, Mosher KI, Shiu A, Ding Z, Zbären N, Gasser P, Guntern P, Yousef H, Castellano JM, Storni F, Graff-Radford N, Britschgi M, Grandgirard D, Hinterbrandner M, Siegrist M, Moullan N, Hofstetter W, Leib SL, Villiger PM, Auwerx J, Villeda SA, Wyss-Coray T, Noti M, Eggel A. Eosinophils regulate adipose tissue inflammation and sustain physical and immunological fitness in old age. Nat Metab 2020; 2:688-702. [PMID: 32694825 PMCID: PMC7438316 DOI: 10.1038/s42255-020-0228-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 05/29/2020] [Indexed: 01/06/2023]
Abstract
Adipose tissue eosinophils (ATEs) are important in the control of obesity-associated inflammation and metabolic disease. However, the way in which ageing impacts the regulatory role of ATEs remains unknown. Here, we show that ATEs undergo major age-related changes in distribution and function associated with impaired adipose tissue homeostasis and systemic low-grade inflammation in both humans and mice. We find that exposure to a young systemic environment partially restores ATE distribution in aged parabionts and reduces adipose tissue inflammation. Approaches to restore ATE distribution using adoptive transfer of eosinophils from young mice into aged recipients proved sufficient to dampen age-related local and systemic low-grade inflammation. Importantly, restoration of a youthful systemic milieu by means of eosinophil transfers resulted in systemic rejuvenation of the aged host, manifesting in improved physical and immune fitness that was partially mediated by eosinophil-derived IL-4. Together, these findings support a critical function of adipose tissue as a source of pro-ageing factors and uncover a new role of eosinophils in promoting healthy ageing by sustaining adipose tissue homeostasis.
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Wang J, von Gunten S, Beldi G, Grandgirard D, Leib SL, Gottstein B. Digest the Sugar, Kill the Parasite: A New Experimental Concept in Treating Alveolar Echinococcosis. Pharmacology 2020; 106:3-8. [PMID: 32739918 DOI: 10.1159/000509355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/11/2020] [Indexed: 11/19/2022]
Abstract
INTRODUCTION The E. multilocularis laminated layer (LL) is a heavily glycosylated parasitic structure that plays an important role in protecting the larval stage (metacestode) of this parasite from physiological and immunological host reactions. We elaborated an experimental design with the idea to modify the (glycan) surface of the LL by a targeted digestion. This should allow the host defense to more easily recognize and attack (or kill) the parasite by immune-mediated effects. METHODS Experimentally, E. multilocularis (clone H95) metacestodes were cultured in vitro with or without addition of α1-3,4,6-galactosidase or β1-3-galactosidase in the medium. Morphological changes were subsequently measured by microscopy at different time points. Parasites were then recovered at day 5 and reinjected into mice for assessing their viability and infectious status. For finally recovered parasites, the respective load was assessed ex vivo by wet weight measurement, and host-related PD1 and IL-10 levels were determined as the key immunoregulators by using flow cytometry. RESULTS Our experiments demonstrated that the parasite vesicular structure can be directly destroyed by adding galactosidases into the in vitro culture system, resulting in the fact that the parasite metacestode vesicles could not anymore infect and develop in mice after this glycan digestion. Moreover, when compared to the mice inoculated with E. multilocularis metacestode without galactosidases, PD1 expression was upregulated in CD4+ Teffs from mice inoculated with E. multilocularis metacestode pretreated with β1-3-galactosidase, with a lower IL-10 secretion from CD4+ Teffs; there was no difference of PD1 and IL-10 expression levels regarding CD4+ Teff from mice inoculated with E. multilocularis metacestode pretreated with α1-3,4,6-galac-tosidase. DISCUSSION We raised our hypothesis that this "aborting" effect may be linked to an altered PD1 and IL-10 response fine-tuning between immunopathology and immune protection. These findings justify a continuation of these experiments upon therapeutical in vivo administration of the enzymes.
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Grädel C, Terrazos Miani MA, Baumann C, Barbani MT, Neuenschwander S, Leib SL, Suter-Riniker F, Ramette A. Whole-Genome Sequencing of Human Enteroviruses from Clinical Samples by Nanopore Direct RNA Sequencing. Viruses 2020; 12:v12080841. [PMID: 32752120 PMCID: PMC7472277 DOI: 10.3390/v12080841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/14/2022] Open
Abstract
Enteroviruses are small RNA viruses that affect millions of people each year by causing an important burden of disease with a broad spectrum of symptoms. In routine diagnostic laboratories, enteroviruses are identified by PCR-based methods, often combined with partial sequencing for genotyping. In this proof-of-principle study, we assessed direct RNA sequencing (DRS) using nanopore sequencing technology for fast whole-genome sequencing of viruses directly from clinical samples. The approach was complemented by sequencing the corresponding viral cDNA via Illumina MiSeq sequencing. DRS of total RNA extracted from three different enterovirus-positive stool samples produced long RNA fragments, covering between 59% and 99.6% of the most similar reference genome sequences. The identification of the enterovirus sequences in the samples was confirmed by short-read cDNA sequencing. Sequence identity between DRS and Illumina MiSeq enterovirus consensus sequences ranged between 94% and 97%. Here, we show that nanopore DRS can be used to correctly identify enterovirus genotypes from patient stool samples with high viral load and that the approach also provides rich metatranscriptomic information on sample composition for all life domains.
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Ricci S, Grandgirard D, Masouris I, Braccini T, Pozzi G, Oggioni MR, Koedel U, Leib SL. Combined therapy with ceftriaxone and doxycycline does not improve the outcome of meningococcal meningitis in mice compared to ceftriaxone monotherapy. BMC Infect Dis 2020; 20:505. [PMID: 32660552 PMCID: PMC7359289 DOI: 10.1186/s12879-020-05226-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/03/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Meningococcal meningitis (MM) is a life-threatening disease associated with approximately 10% case fatality rates and neurological sequelae in 10-20% of the cases. Recently, we have shown that the matrix metalloproteinase (MMP) inhibitor BB-94 reduced brain injury in a mouse model of MM. The present study aimed to assess whether doxycycline (DOX), a tetracycline that showed a neuroprotective effect as adjuvant therapy in experimental pneumococcal meningitis (PM), would also exert a beneficial effect when given as adjunctive therapy to ceftriaxone (CRO) in experimental MM. METHODS BALB/c mice were infected by the intracisternal route with a group C Neisseria meningitidis strain. Eighteen h post infection (hpi), animals were randomised for treatment with CRO [100 mg/kg subcutaneously (s.c.)], CRO plus DOX (30 mg/kg s.c.) or saline (control s.c.). Antibiotic treatment was repeated 24 and 40 hpi. Mouse survival and clinical signs, bacterial counts in cerebella, brain damage, MMP-9 and cyto/chemokine levels were assessed 48 hpi. RESULTS Analysis of bacterial load in cerebella indicated that CRO and CRO + DOX were equally effective at controlling meningococcal replication. No differences in survival were observed between mice treated with CRO (94.4%) or CRO + DOX (95.5%), (p > 0.05). Treatment with CRO + DOX significantly diminished both the number of cerebral hemorrhages (p = 0.029) and the amount of MMP-9 in the brain (p = 0.046) compared to untreated controls, but not to CRO-treated animals (p > 0.05). Levels of inflammatory markers in the brain of mice that received CRO or CRO + DOX were not significantly different (p > 0.05). Overall, there were no significant differences in the parameters assessed between the groups treated with CRO alone or CRO + DOX. CONCLUSIONS Treatment with CRO + DOX showed similar bactericidal activity to CRO in vivo, suggesting no antagonist effect of DOX on CRO. Combined therapy significantly improved mouse survival and disease severity compared to untreated animals, but addition of DOX to CRO did not offer significant benefits over CRO monotherapy. In contrast to experimental PM, DOX has no adjunctive activity in experimental MM.
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Neuenschwander SM, Terrazos Miani MA, Amlang H, Perroulaz C, Bittel P, Casanova C, Droz S, Flandrois JP, Leib SL, Suter-Riniker F, Ramette A. A Sample-to-Report Solution for Taxonomic Identification of Cultured Bacteria in the Clinical Setting Based on Nanopore Sequencing. J Clin Microbiol 2020; 58:e00060-20. [PMID: 32229603 PMCID: PMC7269405 DOI: 10.1128/jcm.00060-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/25/2020] [Indexed: 12/20/2022] Open
Abstract
Amplicon sequencing of the 16S rRNA gene is commonly used for the identification of bacterial isolates in diagnostic laboratories and mostly relies on the Sanger sequencing method. The latter, however, suffers from a number of limitations, with the most significant being the inability to resolve mixed amplicons when closely related species are coamplified from a mixed culture. This often leads to either increased turnaround time or absence of usable sequence data. Short-read next-generation sequencing (NGS) technologies could solve the mixed amplicon issue but would lack both cost efficiency at low throughput and fast turnaround times. Nanopore sequencing developed by Oxford Nanopore Technologies (ONT) could solve those issues by enabling a flexible number of samples per run and an adjustable sequencing time. Here, we report on the development of a standardized laboratory workflow combined with a fully automated analysis pipeline LORCAN (long read consensus analysis), which together provide a sample-to-report solution for amplicon sequencing and taxonomic identification of the resulting consensus sequences. Validation of the approach was conducted on a panel of reference strains and on clinical samples consisting of single or mixed rRNA amplicons associated with various bacterial genera by direct comparison to the corresponding Sanger sequences. Additionally, simulated read and amplicon mixtures were used to assess LORCAN's behavior when dealing with samples with known cross-contamination levels. We demonstrate that by combining ONT amplicon sequencing results with LORCAN, the accuracy of Sanger sequencing can be closely matched (>99.6% sequence identity) and that mixed samples can be resolved at the single-base resolution level. The presented approach has the potential to significantly improve the flexibility, reliability, and availability of amplicon sequencing in diagnostic settings.
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Akello JO, Leib SL, Engler O, Beuret C. Evaluation of Viral RNA Recovery Methods in Vectors by Metagenomic Sequencing. Viruses 2020; 12:v12050562. [PMID: 32438629 PMCID: PMC7290855 DOI: 10.3390/v12050562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 11/16/2022] Open
Abstract
Identification and characterization of viral genomes in vectors including ticks and mosquitoes positive for pathogens of great public health concern using metagenomic next generation sequencing (mNGS) has challenges. One such challenge is the ability to efficiently recover viral RNA which is typically dependent on sample processing. We evaluated the quantitative effect of six different extraction methods in recovering viral RNA in vectors using negative tick homogenates spiked with serial dilutions of tick-borne encephalitis virus (TBEV) and surrogate Langat virus (LGTV). Evaluation was performed using qPCR and mNGS. Sensitivity and proof of concept of optimal method was tested using naturally positive TBEV tick homogenates and positive dengue, chikungunya, and Zika virus mosquito homogenates. The amount of observed viral genome copies, percentage of mapped reads, and genome coverage varied among different extractions methods. The developed Method 5 gave a 120.8-, 46-, 2.5-, 22.4-, and 9.9-fold increase in the number of viral reads mapping to the expected pathogen in comparison to Method 1, 2, 3, 4, and 6, respectively. Our developed Method 5 termed ROVIV (Recovery of Viruses in Vectors) greatly improved viral RNA recovery and identification in vectors using mNGS. Therefore, it may be a more sensitive method for use in arbovirus surveillance.
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Akello JO, Kamgang R, Barbani MT, Suter-Riniker F, Leib SL, Ramette A. Epidemiology of Human Adenoviruses: A 20-Year Retrospective Observational Study in Hospitalized Patients in Bern, Switzerland. Clin Epidemiol 2020; 12:353-366. [PMID: 32308491 PMCID: PMC7147615 DOI: 10.2147/clep.s246352] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/20/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Human adenovirus (HAdV) is an important pathogen seen in clinical practice. Long-term studies may help better understand epidemiological trends and changes in circulating genotypes over time. PURPOSE Using a large biobank of samples from hospitalized, adenovirus-positive patients over a 20-year period, we aimed to analyze long-term epidemiological trends and genotypic relatedness among circulating HAdV strains. METHODS Based on samples from hospitalized patients confirmed to be HAdV positive in Bern, Switzerland, from 1998 to 2017, and on their associated demographic and clinical data, we identified epidemiological trends and risk factors associated with HAdV infection. HAdV genotyping was performed by PCR amplification and sequencing of the hypervariable hexon gene. The obtained sequences were phylogenetically compared with sequences from international HAdV strains. RESULTS HAdV was identified in 1302 samples tested. Cases of HAdV infection were reported throughout the years with no clear seasonality. Upper respiratory tract samples, conjunctivitis swabs, and stool had the highest positivity rate (56.2%, 18.7%, and 14.2% of the cases, respectively). HAdV infection was highest among children ≤4 years old. Increased number of HAdV cases were observed in years 2009 (n = 110) and 2010 (n =112). HAdV8 was the predominant genotype among patients older than 20 years, and was mostly associated with ophthalmic infection. Predominant genotypes among children ≤4 years old were HAdV1, HAdV2, and HAdV3, which were mostly associated with respiratory tract infections. Recurring peaks of increased HAdV cases were evidenced every 4 years among children ≤4 years old. CONCLUSION Our study gives novel insights on long-term epidemiological trends and phylogenetic relatedness among circulating HAdV strains in Switzerland, country in which little data on HAdV prevalence and diversity was so far available.
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Prazak J, Iten M, Cameron DR, Save J, Grandgirard D, Resch G, Goepfert C, Leib SL, Takala J, Jakob SM, Que YA, Haenggi M. Bacteriophages Improve Outcomes in Experimental Staphylococcus aureus Ventilator-associated Pneumonia. Am J Respir Crit Care Med 2020; 200:1126-1133. [PMID: 31260638 DOI: 10.1164/rccm.201812-2372oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Rationale: Infections caused by multidrug-resistant bacteria are a major clinical challenge. Phage therapy is a promising alternative antibacterial strategy.Objectives: To evaluate the efficacy of intravenous phage therapy for the treatment of ventilator-associated pneumonia due to methicillin-resistant Staphylococcus aureus in rats.Methods: In a randomized, blinded, controlled experimental study, we compared intravenous teicoplanin (3 mg/kg, n = 12), a cocktail of four phages (2-3 × 109 plaque-forming units/ml of 2003, 2002, 3A, and K; n = 12), and a combination of both (n = 11) given 2, 12, and 24 hours after induction of pneumonia, and then once daily for 4 days. The primary outcome was survival at Day 4. Secondary outcomes were bacterial and phage densities in lungs and spleen, histopathological scoring of infection within the lungs, and inflammatory biomarkers in blood.Measurements and Main Results: Treatment with either phages or teicoplanin increased survival from 0% to 58% and 50%, respectively (P < 0.005). The combination of phages and antibiotics did not further improve outcomes (45% survival). Animal survival correlated with reduced bacterial burdens in the lung (1.2 × 106 cfu/g of tissue for survivors vs. 1.2 × 109 cfu/g for nonsurviving animals; P < 0.0001), as well as improved histopathological outcomes. Phage multiplication within the lung occurred during treatment. IL-1β increased in all treatment groups over the course of therapy.Conclusions: Phage therapy was as effective as teicoplanin in improving survival and decreasing bacterial load within the lungs of rats infected with methicillin-resistant S. aureus. Combining antibiotics with phage therapy did not further improve outcomes.
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Meyer P, Grandgirard D, Lehner M, Haenggi M, Leib SL. Grafted Neural Progenitor Cells Persist in the Injured Site and Differentiate Neuronally in a Rodent Model of Cardiac Arrest-Induced Global Brain Ischemia. Stem Cells Dev 2020; 29:574-585. [PMID: 31964231 DOI: 10.1089/scd.2019.0190] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hypoxic-ischemic brain injury is the leading cause of disability and death after successful resuscitation from cardiac arrest, and, to date, no specific treatment option is available to prevent subsequent neurofunctional impairments. The hippocampal cornu ammonis segment 1 (CA1) is one of the brain areas most affected by hypoxia, and its degeneration is correlated with memory deficits in patients and corresponding animal models. The aim of this work was to evaluate the feasibility of neural progenitor cell (NPC) transplantation into the hippocampus in a refined rodent cardiac arrest model. Adult rats were subjected to 12 min of potassium-induced cardiac arrest and followed up to 6 weeks. Histological analysis showed extensive neuronal cell death specifically in the hippocampal CA1 segment, without any spontaneous regeneration. Neurofunctional assessment revealed transient memory deficits in ischemic animals compared to controls, detectable after 4 weeks, but not after 6 weeks. Using stereotactic surgery, embryonic NPCs were transplanted in a subset of animals 1 week after cardiac arrest and their survival, migration, and differentiation were assessed histologically. Transplanted cells showed a higher persistence in the CA1 segment of animals after ischemia. Glia in the damaged CA1 segment expressed the chemotactic factor stromal cell-derived factor 1 (SDF-1), while transplanted NPCs expressed its receptor CXC chemokine receptor 4 (CXCR4), suggesting that the SDF-1/CXCR4 pathway, known to be involved in the migration of neural stem cells toward injured brain regions, directs the observed retention of cells in the damaged area. Using immunostaining, we could demonstrate that transplanted cells differentiated into mature neurons. In conclusion, our data document the survival, persistence in the injured area, and neuronal differentiation of transplanted NPCs, and thus their potential to support brain regeneration after hypoxic-ischemic injury. This may represent an option worth further investigation to improve the outcome of patients after cardiac arrest.
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Brackmann M, Leib SL, Tonolla M, Schürch N, Wittwer M. Antimicrobial resistance classification using MALDI-TOF-MS is not that easy: lessons from vancomycin-resistant Enterococcus faecium. Clin Microbiol Infect 2019; 26:391-393. [PMID: 31682986 DOI: 10.1016/j.cmi.2019.10.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/30/2019] [Accepted: 10/24/2019] [Indexed: 10/25/2022]
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Grädel C, Terrazos Miani MA, Barbani MT, Leib SL, Suter-Riniker F, Ramette A. Rapid and Cost-Efficient Enterovirus Genotyping from Clinical Samples Using Flongle Flow Cells. Genes (Basel) 2019; 10:genes10090659. [PMID: 31470607 PMCID: PMC6770998 DOI: 10.3390/genes10090659] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/21/2019] [Accepted: 08/26/2019] [Indexed: 01/22/2023] Open
Abstract
Enteroviruses affect millions of people worldwide and are of significant clinical importance. The standard method for enterovirus identification and genotyping still relies on Sanger sequencing of short diagnostic amplicons. In this study, we assessed the feasibility of nanopore sequencing using the new flow cell “Flongle” for fast, cost-effective, and accurate genotyping of human enteroviruses from clinical samples. PCR amplification of partial VP1 gene was performed from multiple patient samples, which were multiplexed together after barcoding PCR and sequenced multiple times on Flongle flow cells. The nanopore consensus sequences obtained from mapping reads to a reference database were compared to their Sanger sequence counterparts. Using clinical specimens sampled over different years, we were able to correctly identify enterovirus species and genotypes for all tested samples, even when doubling the number of barcoded samples on one flow cell. Average sequence identity across sequencing runs was >99.7%. Phylogenetic analysis showed that the consensus sequences achieved with Flongle delivered accurate genotyping. We conclude that the new Flongle-based assay with its fast turnover time, low cost investment, and low cost per sample represents an accurate, reproducible, and cost-effective platform for enterovirus identification and genotyping.
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