Domingues, F. | Search bioRxiv

bioRxiv2025

Evaluating the antiviral activity of Termin-8 and Finio against a surrogate ASFV-like algal virus

IntroductionAnitox has developed and markets Termin-8 (a formaldehyde-based product) and Finio (non-formaldehyde solution) for the control microbial contamination in feed. To date, both Finio and Termin-8 have not been tested for their potential antiviral activity against megaviruses, such African swine fever virus (ASFV) and its surrogate algal virus, Emiliania huxleyi virus (EhV). Given the limited access and great expense for routine chemical mitigation testing with ASFV, we focused on using EhV as a safe and effective surrogate to evaluate the antiviral activity of these Anitox products. The specific objective of the current study was to evaluate the time course of incubation from hours to days to mimic possible field relevant exposure times for the potential preventative mitigation of megaviruses using Termin-8 and Finio. MethodsEmiliania huxleyi virus was treated with the Anitox recommended concentrations of Termin-8 (0.1% to 0.3% final) and Finio (0.05% to 0.2% final) in biological triplicate experiments. Both viability qPCR (V-qPCR) and standard PCR (S-qPCR) were conducted for EhV copies at 1 hr, 5 hrs, 24 hrs and day 7 post-inoculation. ResultsWe observed that both Termin-8 and Finio, at their highest treatment concentrations, showed the greatest log reduction of 2 and 4.5 log10 units, respectively, at the earliest 1 hr post-inoculation time point. Although Termin-8 efficacy did not improve with time, treatment with Finio showed 100% viable viral inactivation (>5 log10 reduction units) at the lowest concentration after 7 days of exposure. In addition, Finio showed negligible viral DNA removal post-treatment as observed via S-qPCR, but use of Termin-8 resulted in a reduction of viral DNA (S-qPCR) equivalent to that observed using the V-qPCR assay. DiscussionOur results demonstrate for the first time that both Termin-8 and Finio can be used as effective chemical mitigants against megaviruses such as EhV and ASFV. Moreover, the mechanism of chemical mitigation involves degradation of the virus particle itself. However, although Termin-8 efficacy appeared to be less than that of Finio, this is likely not the case because Termin-8 cross-links protein viral capsids and fixes the viral particle to make it non-infectious. With the threat of ASFV introduction into the North American swine industry and other non-infected regions around the world, the use of both Termin-8 and Finio as an effective preventive or mitigation strategy to prevent the transmission of ASFV by reducing particle viability in contaminated feed. Additional research is warranted with ASFV, in the presence of various types of feed ingredients and complete feeds and use bioassays to evaluate infectivity because results from V-qPCR revealed that intact viable particles remain post-treatment.

molecular biology↗

bioRxiv2019

Virulence and antibiotic resistance plasticity of Arcobacter butzleri: insights on the genomic diversity of an emerging human pathogen

Arcobacter butzleri is a food and waterborne bacteria and an emerging human pathogen, frequently displaying a multidrug resistant character. Still, no comprehensive genome-scale comparative analysis has been performed so far, which has limited our knowledge on A. butzleri diversification and pathogenicity. Here, we performed a deep genome analysis of A. butzleri focused on decoding its core- and pan-genome diversity and specific genetic traits underlying its pathogenic potential and diverse ecology. In total, 49 A. butzleri strains (collected from human, animal, food and environmental sources) were screened.\n\nA. butzleri (genome size 2.07-2.58 Mbp) revealed a large open pan-genome with 7474 genes (about 50% being singletons) and a small core-genome with 1165 genes. The core-genome is highly diverse ([≥]55% of the core genes presenting at least 40/49 alleles), being enriched with genes associated with housekeeping functions. In contrast, the accessory genome presented a high proportion of loci with an unknown function, also being particularly overrepresented by genes associated with defence mechanisms. A. butzleri revealed a plastic virulome (including newly identified determinants), marked by the differential presence of multiple adaptation-related virulence factors, such as the urease cluster ureD(AB)CEFG (phenotypically confirmed), the hypervariable hemagglutinin-encoding hecA, a putative type I secretion system (T1SS) harboring another agglutinin potentially related to adherence and a novel VirB/D4 T4SS likely linked to interbacterial competition and cytotoxicity. In addition, A. butzleri harbors a large repertoire of efflux pumps (EPs) (ten \"core\" and nine differentially present) and other antibiotic resistant determinants. We provide the first description of a genetic determinant of macrolides resistance in A. butzleri, by associating the inactivation of a TetR repressor (likely regulating an EP) with erythromycin resistance. Fluoroquinolones resistance correlated with the Thr-85-Ile substitution in GyrA and ampicillin resistance was linked to an OXA-15-like {beta}-lactamase. Remarkably, by decoding the polymorphism pattern of the porin- and adhesin-encoding main antigen PorA, this study strongly supports that this pathogen is able to exchange porA as a whole and/or hypervariable epitope-encoding regions separately, leading to a multitude of chimeric PorA presentations that can impact pathogen-host interaction during infection. Ultimately, our unprecedented screening of short sequence repeats detected potential phase-variable genes related to adaptation and host/environment interaction, such as lipopolysaccharide modification and motility/chemotaxis, suggesting that phase variation likely modulate A. butzleri key adaptive functions.\n\nIn summary, this study constitutes a turning point on A. butzleri comparative genomics revealing that this human gastrointestinal pathogen is equipped with vast virulence and antibiotic resistance arsenals, which, coupled with its remarkable core- and pan-genome diversity, opens a multitude of phenotypic fingerprints for environmental/host adaptation and pathogenicity.\n\nIMPACT STATEMENTDiarrhoeal diseases are the most common cause of human illness caused by foodborne hazards, but the surveillance of diarrhoeal diseases is biased towards the most commonly searched infectious agents (namely Campylobacter jejuni and C. coli). In fact, other less studied pathogens are frequently found as the etiological agent when refined non-selective culture conditions are applied. A hallmark example is the diarrhoeal-causing Arcobacter butzleri which, despite being also associated with extra-intestinal diseases, such as bacteremia in humans and mastitis in animals, and displaying high rates of antibiotic resistance, has not yet been profoundly investigated regarding its epidemiology, diversity and pathogenicity. To overcome the general lack of knowledge on A. butzleri comparative genomics, we provide the first comprehensive genome-scale analysis of A. butzleri focused on exploring the intraspecies virulome content and diversity, resistance determinants, as well as how this pathogen shapes its genome towards ecological adaptation and host invasion. The unveiled scenario of A. butzleri rampant diversity and plasticity reinforces the pathogenic potential of this food and waterborne hazard, while opening multiple research lines that will certainly contribute to the future development of more robust species-oriented diagnostics and molecular surveillance of A. butzleri.\n\nDATA SUMMARYA. butzleri raw sequence reads generated in the present study were deposited in the European Nucleotide Archive (ENA) (BioProject PRJEB34441). The assembled contigs (.fasta and .gbk files), the nucleotide sequences of the predicted transcripts (CDS, rRNA, tRNA, tmRNA, misc_RNA) (.ffn files) and the respective amino acid sequences of the translated CDS sequences (.faa files) are available at http://doi.org/10.5281/zenodo.3434222. Detailed ENA accession numbers, as well as the draft genome statistics are described in Table S1.

genomics↗