Carla Giles

Prevalence of equine adenovirus antibodies in horses in New South Wales, Australia.

There are currently two known serotypes of equine adenovirus (EAdV), equine adenovirus type 1 (EAdV1) and equine adenovirus type 2 (EAdV2); EAdV1 is predominantly associated with upper respiratory tract infections while EAdV2 appears to have a higher association with gastrointestinal infection, however, very little is known about the prevalence of these viruses in horse populations in Australia. In this study we tested 122 serum samples obtained from horses in New South Wales, Australia, using a standard serum neutralization (SN) assay and ELISA. Ninety-seven of the 122 sera displayed had moderate to high titers of antibodies to EAdV1 and/or EAdV2. Eighteen of the 122 sera were positive for both EAdV1 and EAdV2. In contrast, only thirty-seven positive samples were detected using the ELISA. These results suggest that EAdV1 and EAdV2 infections are widely prevalent in the horse population tested and that SN is currently the most suitable assay for the detection of EAdV1 and EAdV2 antibodies in equine serum.

Rhodococcus equi (Prescottella equi) vaccines; the future of vaccine development

For decades researchers have been targeting prevention of Rhodococcus equi (Rhodococcus hoagui/Prescottella equi) by vaccination and the horse breeding industry has supported the ongoing efforts by researchers to develop a safe and cost effective vaccine to prevent disease in foals. Traditional vaccines including live, killed and attenuated (physical and chemical) vaccines have proved to be ineffective and more modern molecular-based vaccines including the DNA plasmid, genetically attenuated and subunit vaccines have provided inadequate protection of foals. Newer, bacterial vector vaccines have recently shown promise for R. equi in the mouse model. This article describes the findings of key research in R. equi vaccine development and looks at alternative methods that may potentially be utilised.

Facile single-step bioconjugation of the antifungal agent caspofungin onto material surfaces via an epoxide plasma polymer interlayer

We report a facile, one-step, aqueous surface bioconjugation approach for producing an antifungal surface coating that prevents the formation of fungal biofilms. By direct reaction between surface epoxide groups and amine groups on caspofungin, it avoids the use of secondary chemicals. The coating withstands washing with detergent and reduces the growth of the fungal pathogens Candida albicans by log 6 and Candida glabrata by log 3. Importantly, we show that surface adsorption of albumin does not inhibit the activity of this antifungal coating.

Chlorine-rich plasma polymer coating for the prevention of attachment of pathogenic fungal cells onto materials surfaces

The attachment of pathogenic fungal cells onto materials surfaces, which is often followed by biofilm formation, causes adverse consequences in a wide range of areas. Here we have investigated the ability of thin film coatings from chlorinated molecules to deter fungal colonization of solid materials by contact killing of fungal cells reaching the surface of the coating. Coatings were deposited onto various substrate materials via plasma polymerization, which is a substrate-independent process widely used for industrial coating applications, using 1,1,2-trichloroethane as the process vapour. XPS surface analysis showed that the coatings were characterized by a highly chlorinated hydrocarbon polymer nature, with only a very small amount of oxygen incorporated. The activity of these coatings against human fungal pathogens was quantified using a recently developed, modified yeast assay and excellent antifungal activity was observed against Candida albicans and Candida glabrata. Plasma polymer surface coatings derived from chlorinated hydrocarbon molecules may therefore offer a promising solution to preventing yeast and mould biofilm formation on materials surfaces, for applications such as air conditioners, biomedical devices, food processing equipment, and others.

Characterisation of the Equine adenovirus 2 genome

Equine adenovirus 2 (EAdV-2) is one of two serotypes of adenoviruses known to infect equines. Initial studies did not associate EAdV-2 infections with any specific clinical syndromes, although more recent evidence suggests that EAdV-2 may be associated with clinical and subclinical gastrointestinal infections of foals and adults respectively. In contrast, Equine adenovirus 1 is well recognised as a pathogen associated with upper respiratory tract infections of horses. In this study the complete genome sequence of EAdV-2 is reported. As expected, genes common to the adenoviruses were identified. Phylogenetic reconstructions using selected EAdV-2 genes confirmed the classification of this virus within the Mastadenovirus genus, and supported the hypothesis that EAdV-2 and EAdV-1 have evolved from separate lineages within the adenoviruses. One spliced open reading frame was identified that encoded for a polypeptide with high similarity to the pIX and E1b_55K adenovirus homologues and was designated pIX_E1b_55K. In addition to this fused version of E1b_55K, a separate E1b_55K encoding gene was also identified. These polypeptides do not appear to have evolved from a gene duplication event as the fused and unfused E1b_55K were most similar to E1b_55K homologues from the Atadenovirus and Mastadenovirus genera respectively. The results of this study suggest that EAdV-2 has an unusual evolutionary history that warrants further investigation.

The importance of fungal pathogens and antifungal coatings in medical device infections

In recent years, increasing evidence has been collated on the contributions of fungal species, particularly Candida, to medical device infections. Fungal species can form biofilms by themselves or by participating in polymicrobial biofilms with bacteria. Thus, there is a clear need for effective preventative measures, such as thin coatings that can be applied onto medical devices to stop the attachment, proliferation, and formation of device-associated biofilms. However, fungi being eukaryotes, the challenge is greater than for bacterial infections because antifungal agents are often toxic towards eukaryotic host cells. Whilst there is extensive literature on antibacterial coatings, a far lesser body of literature exists on surfaces or coatings that prevent attachment and biofilm formation on medical devices by fungal pathogens. Here we review strategies for the design and fabrication of medical devices with antifungal surfaces. We also survey the microbiology literature on fundamental mechanisms by which fungi attach and spread on natural and synthetic surfaces. Research in this field requires close collaboration between biomaterials scientists, microbiologists and clinicians; we consider progress in the molecular understanding of fungal recognition of, and attachment to, suitable surfaces, and of ensuing metabolic changes, to be essential for designing rational approaches towards effective antifungal coatings, rather than empirical trial of coatings.

An Adenoviral Vector Based Vaccine for Rhodococcus equi.

Rhodococcus equi is a respiratory pathogen which primarily infects foals and is endemic on farms around the world with 50% mortality and 80% morbidity in affected foals. Unless detected early and treated appropriately the disease can be fatal. Currently, there is no vaccine available to prevent this disease. For decades researchers have endeavoured to develop an effective vaccine to no avail. In this study a novel human adenoviral vector vaccine for R. equi was developed and tested in the mouse model. This vaccine generated a strong antibody and cytokine response and clearance of R. equi was demonstrated following challenge. These results show that this vaccine could potentially be developed further for use as a vaccine to prevent R. equi disease in foals.