Biology subjects

Rayner, E.

Publications and source records attributed to Rayner, E..

6 recordsLinked to original sources

bioRxiv2025

Trade-offs between phage resistance and conjugative ability shape the ecological and evolutionary response of a multidrug resistance plasmid to plasmid-dependent phage

Phage therapy is a promising alternative to antibiotics to treat multidrug resistant infections. Plasmid dependent phages (PDPs) are particularly attractive as therapeutics because they can both kill targeted pathogen cells, whilst also potentially preventing the further spread of antibiotic resistance genes encoded by plasmids. However, we lack experimental studies of the ecological and evolutionary response of multidrug resistance plasmids against plasmid dependent phage treatment under ecologically relevant scenarios allowing plasmid conjugation. We experimentally evolved populations of E. coli carrying the multidrug resistance RP4 plasmid with the PRD1 PDP under conditions where conjugation was associated with either strong or weak benefits. When opportunities for conjugation were rare, PRD1 only transiently suppressed the conjugative plasmid population due to the rapid evolution of PRD1 resistant plasmids that lacked conjugative ability. Increasing the ecological opportunity for conjugation enhanced plasmid suppression and delayed the evolution of PRD1 resistant plasmids. PRD1 resistance was associated with reduced conjugative ability, but this trade-off was complex due to the heterogeneous impacts of resistance mutations on pilus production and conjugative ability. Mutations and IS element insertions in conjugation genes caused a wide range of PRD1 resistance phenotypes, ranging from complete resistance (virB4) to partial resistance (trbB, trbL). Bioinformatic analysis of publicly available IncP plasmid sequences showed that truncated variants of VirB4 protein are common in natural populations, suggesting that plasmid-dependent phages are an important selective pressure in microbial communities. Our results demonstrate an evolutionary trade-off between conjugative ability and phage resistance that cannot be easily circumvented by plasmids. Targeting multidrug resistance plasmids with PDPs is likely to drive loss of conjugation limiting the transfer of antibiotic resistance genes in bacterial communities.

evolutionary biology↗

bioRxiv2021

Sequential delivery of LAIV and SARS-CoV-2 in the ferret model can reduce SARS-CoV-2 shedding and does not result in enhanced lung pathology.

Co-circulation of SARS-CoV-2 and influenza viruses could pose unpredictable risks to health systems globally, with recent studies suggesting more severe disease outcomes in co-infected patients. The lack of a readily available COVID-19 vaccine has reinforced the importance of influenza vaccine programmes during the COVID-19 pandemic. Live Attenuated Influenza Vaccine (LAIV) is an important tool in protecting against influenza, particularly in children. However, it is unknown whether LAIV administration might influence the outcomes of acute SARS-CoV-2 infection or disease. To investigate this, quadrivalent LAIV (QLAIV) was administered to ferrets 3 days pre- or post-SARS-CoV-2 infection. LAIV administration did not exacerbate SARS-CoV-2 disease course or lung pathology with either regimen. Additionally, LAIV administered prior to SARS-CoV-2 infection significantly reduced SARS-CoV-2 replication and shedding in the upper respiratory tract (URT). We conclude that LAIV administration in close proximity to SARS-CoV-2 infection does not exacerbate mild disease and can reduce SARS-CoV-2 shedding.

microbiology↗

bioRxiv2020

Immunological and pathological outcomes of SARS-CoV-2 challenge after formalin-inactivated vaccine immunisation of ferrets and rhesus macaques

There is an urgent requirement for safe and effective vaccines to prevent novel coronavirus disease (COVID-19) caused by SARS-CoV-2. A concern for the development of new viral vaccines is the potential to induce vaccine-enhanced disease (VED). This was reported in several preclinical studies with both SARS-CoV-1 and MERS vaccines but has not been reported with SARS-CoV-2 vaccines. We have used ferret and rhesus macaques challenged with SARS-CoV-2 to assess the potential for VED in animals vaccinated with formaldehyde-inactivated SARS-CoV-2 (FIV) formulated with Alhydrogel, compared to a negative control vaccine in ferrets or unvaccinated macaques. We showed no evidence of enhanced disease in ferrets or rhesus macaques given FIV except for mild transient enhanced disease seen at seven days post infection in ferrets. This increased lung pathology was observed early in the infection (day 7) but was resolved by day 15. We also demonstrate that formaldehyde treatment of SARS-CoV-2 reduces exposure of the spike receptor binding domain providing a mechanistic explanation for suboptimal immunity.

pathology↗

bioRxiv2020

Prophylactic intranasal administration of a TLR2 agonist reduces upper respiratory tract viral shedding in a SARS-CoV-2 challenge ferret model

Respiratory viruses such as coronaviruses represent major ongoing global threats, causing epidemics and pandemics with huge economic burden. Rapid spread of virus through populations poses an enormous challenge for outbreak control. Like all respiratory viruses, the most recent novel human coronavirus SARS-CoV-2, initiates infection in the upper respiratory tract (URT). Infected individuals are often asymptomatic, yet highly infectious and readily transmit virus. A therapy that restricts initial replication in the URT has the potential to prevent progression of severe lower respiratory tract disease as well as limiting person-to-person transmission. We show that prophylactic intra-nasal administration of the TLR2/6 agonist INNA-051 in a SARS-CoV-2 ferret infection model effectively reduces levels of viral RNA in the nose and throat. The results of our study support clinical development of a therapy based on prophylactic TLR2/6 innate immune activation in the URT to reduce SARS-CoV-2 transmission and provide protection against COVID-19.

immunology↗

bioRxiv2020

Dose-dependent response to infection with SARS-CoV-2 in the ferret model: evidence of protection to re-challenge

In December 2019 an outbreak of coronavirus disease (COVID-19) emerged in Wuhan, China. The causative agent was subsequently identified and named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which rapidly spread worldwide causing a pandemic. Currently there are no licensed vaccines or therapeutics available against SARS-CoV-2 but numerous candidate vaccines are in development and repurposed drugs are being tested in the clinic. There is a vital need for authentic COVID-19 animal models to further our understanding of pathogenesis and viral spread in addition to pre-clinical evaluation of candidate interventions. Here we report a dose titration study of SARS-CoV-2 to determine the most suitable infectious dose to use in the ferret model. We show that a high (5x106 pfu) and medium (5x104 pfu) dose of SARS-CoV-2 induces consistent upper respiratory tract (URT) viral RNA shedding in both groups of six challenged animals, whilst a low dose (5x102 pfu) resulted in only one of six displaying signs of URT viral RNA replication. The URT shedding lasted up to 21 days in the high dose animals with intermittent positive signal from day 14. Sequential culls revealed distinct pathological signs of mild multifocal bronchopneumonia in approximately 5-15% of the lung, observed on day 3 in high and medium dosed animals, with presence of mild broncho-interstitial pneumonia on day 7 onwards. No obvious elevated temperature or signs of coughing or dyspnoea were observed although animals did present with a consistent post-viral fatigue lasting from day 9-14 in the medium and high dose groups. After virus shedding ceased, re-challenged ferrets were shown to be fully protected from acute lung pathology. The endpoints of URT viral RNA replication in addition to distinct lung pathology and post viral fatigue were observed most consistently in the high dose group. This ferret model of SARS-CoV-2 infection presents a mild clinical disease (as displayed by 80% of patients infected with SARS-CoV-2). In addition, intermittent viral shedding on days 14-21 parallel observations reported in a minority of clinical cases.

microbiology↗

bioRxiv2019

A Zika vaccine based on chimpanzee adenovirus ChAdOx1 elicits lineage-transcending sterile immunity and prevents colonisation of brain and ovaries

Introduction Introduction Main Material and Methods Contributions Competing interests References Zika virus (ZIKV) continuous spread has affected more than 80 countries1 and no licenced vaccine is currently available2. The Asian-lineage is the causative agent of major outbreaks across the globe and most of the current ZIKV vaccine candidates aim to provide homologous efficacy in ZIKV pre-clinical challenge models2,3. In contrast, the African-lineage of ZIKV is mainly restricted to sylvatic transmission but not much is known about the ability of this virus to emerge from a sylvatic to human transmission. Efficacy of ZIKV vaccine in mice or macaques relies on the quantification of viraemia by RT-PCR ...

pathology↗