Genome and Metabolome MS-Based Mining of a Marine Strain of Aspergillus affinis

Aspergillus section Circumdati encompasses several species that express both beneficial (e.g., biochemical transformation of steroids and alkaloids, enzymes and metabolites) and harmful compounds (e.g., production of ochratoxin A (OTA)). Given their relevance, it is important to analyze the genetic and metabolic diversity of the species of this section. We sequenced the genome of Aspergillus affinis CMG 70, isolated from sea water, and compared it with the genomes of species from section Circumdati, including A. affinis’s strain type. The A. affinis genome was characterized considering secondary metabolites biosynthetic gene clusters (BGCs), carbohydrate-active enzymes (CAZymes), and transporters. To uncover the biosynthetic potential of A. affinis CMG 70, an untargeted metabolomics (LC-MS/MS) approach was used. Cultivating the fungus in the presence and absence of sea salt showed that A. affinis CMG 70 metabolite profiles are salt dependent. Analyses of the methanolic crude extract revealed the presence of both unknown and well-known Aspergillus compounds, such as ochratoxin A, anti-viral (e.g., 3,5-Di-tert-butyl-4-hydroxybenzoic acid and epigallocatechin), anti-bacterial (e.g., 3-Hydroxybenzyl alcohol, L-pyroglutamic acid, lecanoric acid), antifungal (e.g., L-pyroglutamic acid, 9,12,13-Trihydroxyoctadec-10-enoic acid, hydroxyferulic acid), and chemotherapeutic (e.g., daunomycinone, mitoxantrone) related metabolites. Comparative analysis of 17 genomes from 16 Aspergillus species revealed abundant CAZymes (568 per species), secondary metabolite BGCs (73 per species), and transporters (1359 per species). Some BGCs are highly conserved in this section (e.g., pyranonigrin E and UNII-YC2Q1O94PT (ACR toxin I)), while others are incomplete or completely lost among species (e.g., bikaverin and chaetoglobosins were found exclusively in series Sclerotiorum, while asperlactone seemed completely lost). The results of this study, including genome analysis and metabolome characterization, emphasize the molecular diversity of A. affinis CMG 70, as well as of other species in the section Circumdati.

Post-discharge decolonization of patients harboring methicillin-resistant Staphylococcus aureus (MRSA) USA300 strains: secondary analysis of the CLEAR Trial

The CLEAR Trial recently found that decolonization reduced infections and hospitalizations in MRSA carriers in the year following hospital discharge. In this secondary analysis, we explored whether decolonization had a similar benefit in the subgroup of trial participants who harbored USA300, using two different definitions for the USA300 strain-type.

EDL933 Strains of Escherichia coli O157 can Demonstrate Genetic Diversity and Differential Adherence to Bovine Recto-Anal Junction Squamous Epithelial Cells

Background: Differences between Escherichia coli O157 (O157) strains are well-established with some of these strains being associated with major outbreaks in the US. EDL933 is one such O157 strain that caused a multistate outbreak in 1982 and has since been used as a prototype in various O157-related experiments. Objective: As O157 can readily acquire genetic mutations, we sought to determine if the genetic and phenotypic profiles of EDL933 strains from different sources would be consistent. Methods: We evaluated wild-type O157 strains stocked as EDL933 from three different laboratories, in the strain typing Polymorphic Amplified Typing Sequence (PATS) and the bovine rectal-anal junction squamous epithelial (RSE) cell- and HEp-2 cell- adherence assays. In addition, we also verified if Shiga toxins (Stx), the Locus of Enterocyte Effacement (LEE) or curli fimbriae contributed to the adherence phenotypes observed using mutant and wild-type EDL933 isolates. Results: Our results showed differences in PATS profiles and RSE cell-adherence phenotype, with no influence from the Stx or LEE genes, between EDL933 from different sources. Interestingly, the EDL933 strain that demonstrated the most contrasting diffuse adherence phenotype on RSE cells, EDL933-T, had decreased curli production that may have contributed to this phenotype. Conclusion: Our observations suggest that a comprehensive characterization of bacterial isolates, even if assigned to the same strain type prior to use in experiments, is warranted to ensure consistency and reproducibility of results.

The M2 Gene Is a Determinant of Reovirus-Induced Myocarditis

Although a broad range of viruses cause myocarditis, the mechanisms that underlie viral myocarditis are poorly understood. Here, we report that the M2 gene is a determinant of reovirus myocarditis. The M2 gene encodes outer capsid protein μ1, which mediates host membrane penetration during reovirus entry. We infected newborn C57BL/6 mice with reovirus strain type 1 Lang (T1L) or a reassortant reovirus in which the M2 gene from strain type 3 Dearing (T3D) was substituted into the T1L genetic background (T1L/T3DM2). T1L was non-lethal in wild-type mice, whereas greater than 90% of mice succumbed to T1L/T3DM2 infection. T1L/T3DM2 produced higher viral loads than T1L at the site of inoculation. In secondary organs, T1L/T3DM2 was detected with more rapid kinetics and reached higher peak titers than T1L. We found that hearts from T1L/T3DM2-infected mice were grossly abnormal, with large lesions indicative of substantial inflammatory infiltrate. Lesions in T1L/T3DM2-infected mice contained necrotic cardiomyocytes with pyknotic debris, and extensive lymphocyte and histiocyte infiltration. In contrast, T1L induced the formation of small purulent lesions in a small subset of animals, consistent with T1L being mildly myocarditic. Finally, more activated caspase-3-positive cells were observed in hearts from animals infected with T1L/T3DM2 compared to T1L. Together, our findings indicate that substitution of the T3D M2 allele into an otherwise T1L genetic background is sufficient to change a non-lethal infection into a lethal infection. Our results further indicate that T3D M2 enhances T1L replication and dissemination in vivo , which potentiates the capacity of reovirus to cause myocarditis. IMPORTANCE Reovirus is a non-enveloped virus with a segmented double-stranded RNA genome that serves as a model for studying viral myocarditis. The mechanisms by which reovirus drives myocarditis development are not fully elucidated. We found that substituting the M2 gene from strain type 3 Dearing (T3D) into an otherwise type 1 Lang (T1L) genetic background (T1L/T3DM2) was sufficient to convert the non-lethal T1L strain into a lethal infection in neonatal C57BL/6 mice. T1L/T3DM2 disseminated more efficiently and reached higher maximum titers than T1L in all organs tested, including the heart. T1L is mildly myocarditic and induced small areas of cardiac inflammation in a subset of mice. In contrast, hearts from mice infected with T1L/T3DM2 contained extensive cardiac inflammatory infiltration and more activated caspase-3-positive cells, which is indicative of apoptosis. Together, our findings identify the reovirus M2 gene as a new determinant of reovirus-induced myocarditis.

Current COVID-19 vaccine epidemiology and dentistry

The coronavirus disease 2019 (COVID-19) vaccine story is continuously unfolding. Since our previous COVID-19 commentaries, much new information has transpired on the subject, and here we revisit this topic, which has practical implications for all stakeholders in dentistry, as well as the public. This article, on current vaccine epidemiology, provides an account of why vaccines fail in general, and the particular concerns in relation to the new Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and related ‘variants of concern’. Issues related to vaccine failure are fundamentally dichotomous in nature, appertaining either to the vaccine strain (type) per se, and/or the numerous endogenous factors of the vaccine recipient/vaccinee. Societal factors such as vaccine hesitancy and its impact on herd immunity appear to overarch the long-term goal of total or partial global suppression of SARS-CoV-2, and its eventual endemicity. CPD/Clinical Relevance: To describe the reasons for the failure of currently administered COVID-19 vaccines, particularly in relation to the advent of the SARS-CoV-2 ‘variants of concern’, and discuss implications for clinical dental practice.

1170. Do Rotavirus Strains Affect Vaccine Effectiveness? A Systematic Review And Meta-analysis

Background Rotavirus causes 215,000 deaths from severe childhood diarrhea annually. Two rotavirus vaccines – a monovalent vaccine containing a single rotavirus strain (RV1) and a pentavalent vaccine containing 5 rotavirus strains (RV5) – are used in routine immunization programs of nearly 100 countries. Concerns exist that rotavirus vaccines may be less effective against rotavirus strains not contained in the vaccines which could subsequently cause selective pressure and strain replacement. We estimated the vaccine effectiveness (VE) of RV1 and RV5 against vaccine (homotypic) and non-vaccine (partially and fully heterotypic) strains. Methods After conducting a systematic review, we meta-analyzed 31 case-control studies (N=27,293) conducted between 2006 and 2020 using a random-effect regression model. Results In high-income countries, RV1 VE was 10% lower against partially heterotypic (p-value=0.04) and fully heterotypic (p-value=0.10) compared to homotypic strains (homotypic VE: 90% [95% CI: 82, 94]; partially heterotypic VE: 79% [95% CI: 71, 85]; fully heterotypic VE: 80% [95% CI: 65, 88]; Figure 1). In middle-income countries, RV1 VE was 14 to 16% lower against partially heterotypic (p-value=0.06) and fully heterotypic (p-value=0.04) compared to homotypic strains (homotypic VE: 81% [95% CI: 69, 88]; partially heterotypic VE: 67% [95% CI: 54, 76]; fully heterotypic VE: 65% [95% CI: 52, 75]; Figure 1). Strain-specific RV5 VE differences were less pronounced (Figure 2). Limited data were available from low-income countries. Figure 1. Vaccine effectiveness by country income level and strain type, for RV1. Figure 2. Vaccine effectiveness by country income level and strain type, for RV5. Conclusion Vaccine effectiveness of RV1 and RV5 was somewhat lower VE against non-vaccine than vaccine strains. Ongoing surveillance is crucial to continue long-term monitoring for strain replacement, particularly in low-income settings where data are limited. Disclosures All Authors: No reported disclosures

Food Enzyme Database (FEDA): a web application gathering information about food enzyme preparations available on the European market

Following the European Commission No. 1332/2008 regulation and the consequent necessity of a scientific evaluation of food enzymes (FEs) for their approval for sale on the European Union market, many FE dossiers have been submitted to the European Commission and various documents currently co-exist. In order to centralize all relevant information in one structured location that is easily accessible to support enforcement laboratories and the competent authorities, we developed a web application, called Food Enzyme Database (FEDA). FEDA allows searching and collection of information originating from many different sources in one centralized portal. Queries can be performed using key information types, which include information on the producing company, production source (strain type, genetically modified microorganism status), type of enzyme protein and evaluation status with employed evaluation criteria. The database contains all current publicly available information. Centralizing all information coupled with intuitive searching functionality also allows the generation of general statistics regarding the current market situation. FEDA is open access and is freely available at the following location: https://feda.sciensano.be. Database URL : https://feda.sciensano.be

Treponema pallidum macrolide resistance and molecular epidemiology in southern Africa, 2008-2018

Treponema pallidum macrolide resistance and clinical treatment failure have emerged rapidly within communities where macrolides have been used as convenient, oral therapeutic alternatives to benzathine penicillin G for syphilis, or for other clinical indications. Macrolides are not included in the South African syndromic management guidelines for genital ulcer disease; however, in 2015, a 1 gram dose of azithromycin was incorporated into treatment algorithms for genital discharge. We determined the prevalence of 23S rRNA macrolide resistance-associated point mutations in 135 T. pallidum -positive surveillance specimens from Botswana, Zimbabwe and South Africa between 2008 and 2018. Additionally, we investigated the association between macrolide resistance, T. pallidum strain type and HIV co-infection. A significant increase in the prevalence of the A2058G macrolide resistance-associated point mutation was observed in specimens collected after 2015. There was a high level of molecular heterogeneity among T. pallidum strains circulating in the study communities, with strain type 14d/f being the most predominant in South Africa. Fourteen novel strain types, derived from three new tpr -gene restriction fragment length polymorphism patterns and seven new tp0548 -gene sequence types, were identified. There was an association between A2058G-associated macrolide resistance and T. pallidum strain types 14d/f and 14d/g, but no association between T. pallidum macrolide resistance and HIV co-infection. The majority of T. pallidum strains, as well as strains containing the A2058G mutation, belonged to the SS14-like clade. This is the first study to extensively detail the molecular epidemiology and emergence of macrolide resistance in T. pallidum in southern Africa.

The M2 Gene Is a Determinant of Reovirus-Induced Myocarditis

Although a broad range of viruses cause myocarditis, the mechanisms that underlie viral myocarditis are poorly understood. Here, we report that the M2 gene is a determinant of reovirus myocarditis. The reovirus M2 gene encodes outer capsid protein µ1, which influences both cell entry and cell death. We infected newborn mice with reovirus strain type 1 Lang (T1L) or a reassortant reovirus in which the M2 gene from strain type 3 Dearing (T3D) was substituted into the T1L background (T1L/T3DM2). T1L was non-lethal in wild-type mice, whereas ~ 90% of mice succumbed to T1L/T3DM2. T1L/T3DM2 produced higher viral loads than T1L at the site of inoculation. In secondary organs, T1L/T3DM2 was detected with more rapid kinetics and reached higher peak titers than T1L. We found that hearts from T1L/T3DM2-infected mice were grossly abnormal, with large lesions corresponding to substantial cardiac injury with inflammatory infiltrates. Lesions in T1L/T3DM2-infected mice contained aggregates of necrotic cardiomyocytes with pyknotic debris, and prominent lymphocyte and histiocyte infiltration. In contrast, T1L induced the formation of smaller lesions in a subset of animals, consistent with T1L being mildly myocarditic. Finally, more activated caspase-3-positive cells were observed in hearts from animals infected with T1L/T3DM2 compared to T1L. Together, our findings indicate that substitution of the T3D M2 allele into an otherwise T1L genetic background is sufficient to change a non-lethal infection into a lethal infection. Our results further indicate that T3D M2 enhances T1L replication and dissemination in vivo, which potentiates the capacity of reovirus to cause myocarditis.