Lytic activity of phages against bacterial pathogens infecting diabetic foot ulcers.

Complications of diabetes, such as diabetic foot ulcers (DFUs), are common, multifactorial in origin, and costly to treat. DFUs are the cause of nearly 90% of limb amputations among persons with diabetes. In most chronic infections such as DFU, biofilms are involved. Bacteria in biofilms are 100-1000 times more resistant to antibiotics than their planktonic counterparts. Multidrug-resistant (MDR) Staphylococcus aureus and Pseudomonas aeruginosa infections in DFUs may require alternative therapeutic agents such as bacteriophages ("phages"). This study describes the lytic activity of phage cocktails AB-SA01 (3-phage cocktail) and AB-PA01 (4-phage cocktail), which target S. aureus and P. aeruginosa, respectively. The host range and lytic effect of AB-SA01 and AB-PA01 on a planktonic culture, single-species biofilm, and mixed-species biofilm were evaluated. In vitro testing showed that 88.7% of S. aureus and 92.7% of P. aeruginosa isolates were susceptible to AB-SA01 and AB-PA01, respectively, in the planktonic state. The component phages of AB-SA01 and AB-PA01 infected 66% to 94.3% of the bacterial isolates tested. Furthermore, AB-SA01 and AB-PA01 treatment significantly (p < 0.05) reduced the biofilm biomass of their hosts, regardless of the antibiotic-resistant characteristics of the isolates and the presence of a non-susceptible host. In conclusion, the strong lytic activity, broad host range, and significant biofilm biomass reduction of AB-SA01 and AB-PA01 suggest the considerable potential of phages in treating antibiotic-resistant S. aureus and P. aeruginosa infections alone or as coinfections in DFUs.

Inactivation of human coronaviruses using an automated room disinfection device.

The emergence of more virulent and epidemic strains of viruses, especially in the context of COVID-19, makes it more important than ever to improve methods of decontamination. The objective of this study was to evaluate the potential of on-demand production of chlorine species to inactivate human coronaviruses. The commercial prototype disinfection unit was provided by Unipolar Water Technologies. The Unipolar device generates active chlorine species using an electrochemical reaction and dispenses the disinfectant vapour onto surfaces with an aspirator. The minimum effective concentration and exposure time of disinfectant were evaluated on human hepatoma (Huh7) cells using 50% tissue culture infectious dose (TCID50) assay and human coronavirus 229E (HCoV-229E), a surrogate for pathogenic human coronaviruses. We showed that chlorine species generated in the Unipolar device inactivate HCoV-229E on glass surfaces at ≥ 400 parts per million active chlorine concentration with a 5 min exposure time. Here, inactivation refers to the inability of the virus to infect the Huh7 cells. Importantly, no toxic effect was observed on Huh7 cells for any of the active chlorine concentrations and contact times tested.

Thirty-Day Unplanned Readmissions Following Hospitalisation for Atrial Fibrillation in Australia and New Zealand.

AIMS: Atrial fibrillation (AF) is a leading cause of hospitalisations, yet little is known about 30-day readmissions following discharge despite increasing policy focus on reducing readmissions. We assessed the rate, timing, causes and predictors of 30-day unplanned readmission following an acute and elective AF hospitalisation using population-wide data. METHODS: We studied all patients hospitalised for AF from 2010 to 2015 at all public and most private hospitals in Australia and New Zealand. The main outcome measures were unplanned readmissions within 30 days of discharge, primary diagnosis associated with these readmissions, and their predictors as modelled by logistic regression. RESULTS: Among 301,654 patients hospitalised for AF (mean age 69.2±13.6 yrs, 55.6% female, 65.2% acute presentations), 29,750 (9.9%) experienced an unplanned readmission within 30 days with 62.6% occurring by 14 days. Unplanned readmissions occurred more frequently following an acute versus elective AF hospitalisations (12.5% vs 4.9%, p<0.001). The most common diagnoses associated with readmissions were recurrence of AF (n=9,890, 33.2%), and preventable conditions including heart failure (n=2,683, 9.0%), pneumonia (n=724, 2.4%) and acute myocardial infarction (n=510, 1.7%). A higher risk of 30-day readmission was associated with congenital cardiac/circulatory defect (OR 2.18, CI 1.44-3.30), congestive heart failure (OR 1.34, CI 1.30-1.39), and arrhythmia/conduction disorders (OR 1.25, CI 1.21-1.28). CONCLUSION: Almost 1 in 10 AF hospitalisations resulted in unplanned readmission within 30-days, mostly for AF recurrence. Improved clinical management of AF and transitional care planning are required to reduce unplanned readmissions following AF hospitalisations.

Incidence and causes of early unplanned readmission after hospitalisation with peripheral arterial disease in Australia and New Zealand.

OBJECTIVE: To evaluate the characteristics and predictors of unplanned readmission within 30 days of hospitalisation for the treatment of peripheral arterial disease (PAD) in Australia and New Zealand. DESIGN: Analysis of hospitalisations data in the Admitted Patient Collection for each Australian state and territory and the New Zealand National Minimum Dataset (Hospital Events). SETTING: All public and 80% of private hospitals in Australia and New Zealand. PARTICIPANTS: Adults (18 years or older) hospitalised with a primary or conditional secondary diagnosis of PAD during 1 January 2010 - 31 December 2015. MAIN OUTCOME MEASURE: Rate of unplanned readmission (any cause) within 30 days of hospitalisation with PAD. RESULTS: Of 104 979 admissions included in our analysis (mean patient age, 73.7 years; SD, 12.4 years), 9765 were followed by at least one unplanned readmission within 30 days of discharge (9.3%): 3395 within one week (34.8%) and 7828 within three weeks (80.2%). The most frequent readmission primary diagnoses were atherosclerosis (1477, 15.3%), type 2 diabetes (1057, 10.8%), and "complications of procedures not elsewhere classified" (963, 9.9%). Readmission was more frequent after acute (4830 of 26 304, 18.4%) than elective PAD hospitalisations (4935 of 78 675, 6.3%), but the readmission characteristics were similar. Factors associated with greater likelihood of readmission included acute PAD hospitalisations (odds ratio [OR], 2.04; 95% CI, 1.96-2.17), surgical intervention during the PAD hospitalisation (OR, 1.74; 95% CI, 1.64-1.84), and chronic limb-threatening ischaemia (OR, 1.55; 95% CI, 1.47-1.63). CONCLUSION: Unplanned readmissions within 30 days of hospitalisation for PAD are often for potentially preventable reasons. Their number should be reduced to improve clinical outcomes for people with PAD.

Marine mollusc extracts-Potential source of SARS-CoV-2 antivirals.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel human coronavirus and the causative agent of coronavirus disease 2019 (Covid-19). There is an urgent need for effective antivirals to treat current Covid-19 cases and protect those unable to be vaccinated against SARS-CoV-2. Marine molluscs live in an environment containing high virus densities (>107 virus particles per ml), and there are an estimated 100,000 species in the phylum Mollusca, demonstrating the success of their innate immune system. Mollusc-derived antivirals are yet to be used clinically despite the activity of many extracts, including against human viruses, being demonstrated in vitro. Hemolymph of the Pacific oyster (Crassostrea gigas) has in vitro antiviral activity against herpes simplex virus and human adenovirus, while antiviral action against SARS-CoV-2 has been proposed by in silico studies. Such evidence suggests that molluscs, and in particular C. gigas hemolymph, may represent a source of antivirals for human coronaviruses.

Potential for bacteriophage therapy for Staphylococcus aureus pneumonia with influenza A coinfection.

The ability of influenza A virus to evolve, coupled with increasing antimicrobial resistance, could trigger an influenza pandemic with great morbidity and mortality. Much of the 1918 influenza pandemic mortality was likely due to bacterial coinfection, including Staphylococcus aureus pneumonia. S. aureus resists many antibiotics. The lack of new antibiotics suggests alternative antimicrobials, such as bacteriophages, are needed. Potential delivery routes for bacteriophage therapy (BT) include inhalation and intravenous injection. BT has recently been used successfully in compassionate access pulmonary infection cases. Phage lysins, enzymes that hydrolyze bacterial cell walls and which are bactericidal, are efficacious in animal pneumonia models. Clinical trials will be needed to determine whether BT can ameliorate disease in influenza and S. aureus coinfection.

Efficacy of phage cocktail AB-SA01 therapy in diabetic mouse wound infections caused by multidrug-resistant Staphylococcus aureus.

BACKGROUND: Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus. Antibiotic-resistant Staphylococcus aureus is frequently isolated from DFU infections. Bacteriophages (phages) represent an alternative or adjunct treatment to antibiotic therapy. Here we describe the efficacy of AB-SA01, a cocktail of three S. aureus Myoviridae phages, made to current good manufacturing practice (cGMP) standards, and which has undergone two phase I clinical trials, in treatment of multidrug-resistant (MDR) S. aureus infections. RESULTS: Wounds of saline-treated mice showed no healing, but expanded and became inflamed, ulcerated, and suppurating. In contrast, AB-SA01 treatment decreased the bacterial load with efficacy similar or superior to vancomycin treatment. At the end of the treatment period, there was a significant decrease (p < 0.001) in bacterial load and wound size in infected phage- and vancomycin-treated groups compared with infected saline-treated mice. In phage-treated mice, wound healing was seen similar to vancomycin treatment. No mortality was recorded associated with infections, and post-mortem examinations did not show any evident pathological lesions other than the skin wounds. No adverse effects related to the application of phages were observed. CONCLUSION: Topical application of phage cocktail AB-SA01 is effective, as shown by bacterial load reduction and wound closure, in the treatment of diabetic wound infections caused by MDR S. aureus. Our results suggest that topical phage cocktail treatment may be effective in treating antibiotic-resistant S. aureus DFU infections.

Tenth Scientific Biennial Meeting of the Australasian Virology Society-AVS10 2019.

The Australasian Virology Society (AVS) aims to promote, support and advocate for the discipline of virology in the Australasian region. The society was incorporated in 2011 after 10 years operating as the Australian Virology Group (AVG) founded in 2001, coinciding with the inaugural biennial scientific meeting. AVS conferences aim to provide a forum for the dissemination of all aspects of virology, foster collaboration, and encourage participation by students and post-doctoral researchers. The tenth Australasian Virology Society (AVS10) scientific meeting was held on 2-5 December 2019 in Queenstown, New Zealand. This report highlights the latest research presented at the meeting, which included cutting-edge virology presented by our international plenary speakers Ana Fernandez-Sesma and Benjamin tenOever, and keynote Richard Kuhn. AVS10 honoured female pioneers in Australian virology, Lorena Brown and Barbara Coulson. We report outcomes from the AVS10 career development session on "Successfully transitioning from post-doc to lab head", winners of best presentation awards, and the AVS gender equity policy, initiated in 2013. Plans for the 2021 meeting are underway which will celebrate the 20th anniversary of AVS where it all began, in Fraser Island, Queensland, Australia.

Efficacy of Lytic Phage Cocktails on Staphylococcus aureus and Pseudomonas aeruginosa in Mixed-Species Planktonic Cultures and Biofilms.

The efficacy of phages in multispecies infections has been poorly examined. The in vitro lytic efficacies of phage cocktails AB-SA01, AB-PA01, which target Staphylococcus aureus and Pseudomonas aeruginosa, respectively, and their combination against their hosts were evaluated in S. aureus and P. aeruginosa mixed-species planktonic and biofilm cultures. Green fluorescent protein (GFP)-labelled P. aeruginosa PAO1 and mCherry-labelled S. aureus KUB7 laboratory strains and clinical isolates were used as target bacteria. During real-time monitoring using fluorescence spectrophotometry, the density of mCherry S. aureus KUB7 and GFP P. aeruginosa PAO1 significantly decreased when treated by their respective phage cocktail, a mixture of phage cocktails, and gentamicin. The decrease in bacterial density measured by relative fluorescence strongly associated with the decline in bacterial cell counts. This microplate-based mixed-species culture treatment monitoring through spectrophotometry combine reproducibility, rapidity, and ease of management. It is amenable to high-throughput screening for phage cocktail efficacy evaluation. Each phage cocktail, the combination of the two phage cocktails, and tetracycline produced significant biofilm biomass reduction in mixed-species biofilms. This study result shows that these phage cocktails lyse their hosts in the presence of non-susceptible bacteria. These data support the use of phage cocktails therapy in infections with multiple bacterial species.

Economic evaluations considering costs and outcomes of diabetic foot ulcer infections: A systematic review.

BACKGROUND: Diabetic foot ulcer (DFU) is a severe complication of diabetes and particularly susceptible to infection. DFU infection intervention efficacy is declining due to antimicrobial resistance and a systematic review of economic evaluations considering their economic feasibility is timely and required. AIM: To obtain and critically appraise all available full economic evaluations jointly considering costs and outcomes of infected DFUs. METHODS: A literature search was conducted across MedLine, CINAHL, Scopus and Cochrane Database seeking evaluations published from inception to 2019 using specific key concepts. Eligibility criteria were defined to guide study selection. Articles were identified by screening of titles and abstracts, followed by a full-text review before inclusion. We identified 352 papers that report economic analysis of the costs and outcomes of interventions aimed at diabetic foot ulcer infections. Key characteristics of eligible economic evaluations were extracted, and their quality assessed against the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist. RESULTS: 542 records were screened and 39 full-texts assessed for eligibility. A total of 19 papers were included in the final analysis. All studies except one identified cost-saving or cost-effective interventions. The evaluations included in the final analysis were so heterogeneous that comparison of them was not possible. All studies were of "excellent", "very good" or "good" quality when assessed against the CHEERS checklist. CONCLUSIONS: Consistent identification of cost-effective and cost-saving interventions may help to reduce the DFU healthcare burden. Future research should involve clinical implementation of interventions with parallel economic evaluation rather than model-based evaluations.

The microbial abundance dynamics of the paediatric oral cavity before and after sleep.

Objective: Microhabitats in the oral cavity differ in microbial taxonomy. However, abundance variations of bacterial and viral communities within these microhabitats are not fully understood. Aims and Hypothesis: To assess the spatial distribution and dynamics of the microbial abundances within 6 microhabitats of the oral cavity before and after sleep. We hypothesise that the abundance distributions of these microbial communities will differ among oral sites. Methods: Using flow cytometry, bacterial and virus-like particle (VLP) abundances were enumerated for 6 oral microhabitats before and after sleep in 10 healthy paediatric sleepers. Results: Bacterial counts ranged from 7.2 ± 2.8 × 105 at the palate before sleep to 1.3 ± 0.2 × 108 at the back of the tongue after sleep, a difference of 187 times. VLPs ranged from 1.9 ± 1.0 × 106 at the palate before sleep to 9.2 ± 5.0 × 107 at the back of the tongue after sleep, a difference of 48 times. Conclusion: The oral cavity is a dynamic numerically heterogeneous environment where microbial communities can increase by a count of 100 million during sleep. Quantification of the paediatric oral microbiome complements taxonomic diversity information to show how biomass varies and shifts in space and time.

A systematic review protocol for examining 30-day readmission costs for atrial fibrillation patients.

INTRODUCTION: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and readmissions of AF patients place a huge burden on the healthcare system, including economically. With an increasing prevalence, the burden of AF will continue evolving. To illuminate the readmission-specific economic burden, we aim to provide quality evidence on the cost of readmissions within 30 days where AF has been the primary diagnosis at the index admission. METHODS AND ANALYSIS: We will conduct a systematic review of all peer-reviewed articles examining readmission costs for AF patients. We will search MedLine, Cumulative Index to Nursing and Allied Health Literature, Scopus and Cochrane Library for articles written in English, published in peer-reviewed journals from inception to 2019. Reporting of this protocol follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols checklist. Studies will be included if patients were aged 18 years and over, AF was the primary diagnosis of index admission and costs of readmission within 30 days were reported. Quality assessment of studies will be done using a modified Evers checklist. Study results will be summarised in a Forest plot and heterogeneity tested for using the Cochran's Q and I2 statistic. A random-effects model will be applied for meta-analysis if studies are sufficiently homogeneous. The cost of readmission to hospital within 30 days for AF patients is the main outcome of interest while additional outcomes are 30-day readmission rate, predictors of readmission and predictors of readmission costs. ETHICS AND DISSEMINATION: Formal ethical approval is not required as no patients will be involved. Dissemination of results will be through a peer-reviewed publication. PROSPERO REGISTRATION NUMBER: CRD42019132017.

Mini-review: efficacy of lytic bacteriophages on multispecies biofilms.

There is potential for phages to prevent and control bacterial biofilms, but few studies have examined the effect of phages on the multispecies biofilms that characterize most bacterial infections. This paper reviews the mechanism of action of phages, the evidence supporting the view that phage therapy will be effective against bacterial targets and the opposite viewpoint, phage application approaches, and the comparative advantage of phage therapy in multispecies biofilms. The few reports measuring the actions of lytic phages against multispecies biofilms are also reviewed. The authors are cautiously optimistic about the application of phages against their targets when in multispecies biofilms because some lysis mechanisms do not require species specificity.

Antiviral Defense and Innate Immune Memory in the Oyster.

The Pacific oyster, Crassostrea gigas, is becoming a valuable model for investigating antiviral defense in the Lophotrochozoa superphylum. In the past five years, improvements to laboratory-based experimental infection protocols using Ostreid herpesvirus I (OsHV-1) from naturally infected C. gigas combined with next-generation sequencing techniques has revealed that oysters have a complex antiviral response involving the activation of all major innate immune pathways. Experimental evidence indicates C. gigas utilizes an interferon-like response to limit OsHV-1 replication and spread. Oysters injected with a viral mimic (polyI:C) develop resistance to OsHV-1. Improved survival following polyI:C injection was found later in life (within-generational immune priming) and in the next generation (multi-generational immune priming). These studies indicate that the oyster's antiviral defense system exhibits a form of innate immune-memory. An important priority is to identify the molecular mechanisms responsible for this phenomenon. This knowledge will motivate the development of practical and cost-effective treatments for improving oyster health in aquaculture.