Deletion of the EP402R Gene from the Genome of African Swine Fever Vaccine Strain ASFV-G-∆I177L Provides the Potential Capability of Differentiating between Infected and Vaccinated Animals.

The African swine fever virus (ASFV) mutant ASFV-G-∆I177L is a safe and efficacious vaccine which induces protection against the challenge of its parental virus, the Georgia 2010 isolate. Although a genetic DIVA (differentiation between infected and vaccinated animals) assay has been developed for this vaccine, still there is not a serological DIVA test for differentiating between animals vaccinated with ASFV-G-∆I177L and those infected with wild-type viruses. In this report, we describe the development of the ASFV-G-∆I177L mutant having deleted the EP402R gene, which encodes for the viral protein responsible for mediating the hemadsorption of swine erythrocytes. The resulting virus, ASFV-G-∆I177L/∆EP402R, does not have a decreased ability to replicates in swine macrophages when compared with the parental ASFV-G-∆I177L. Domestic pigs intramuscularly (IM) inoculated with either 102 or 106 HAD50 of ASFV-G-∆I177L/∆EP402R remained clinically normal, when compared with a group of mock-vaccinated animals, indicating the absence of residual virulence. Interestingly, an infectious virus could not be detected in the blood samples of the ASFV-G-∆I177L/∆EP402R-inoculated animals in either group at any of the time points tested. Furthermore, while all of the mock-inoculated animals presented a quick and lethal clinical form of ASF after the intramuscular inoculation challenge with 102 HAD50 of highly virulent parental field isolate Georgia 2010 (ASFV-G), all of the ASFV-G-∆I177L/∆EP402R-inoculated animals were protected, remaining clinically normal until the end of the observational period. Most of the ASFV-G-∆I177L/∆EP402R-inoculated pigs developed strong virus-specific antibody responses against viral antigens, reaching maximum levels at 28 days post inoculation. Importantly, all of the sera collected at that time point in the ASFV-G-∆I177L/∆EP402R-inoculated pigs did not react in a direct ELISA coated with the recombinant EP402R protein. Conversely, the EP402R protein was readily recognized by the pool of sera from the animals immunized with recombinant live attenuated vaccine candidates ASFV-G-∆I177L, ASFV-G-∆MGF, or ASFV-G-∆9GL/∆UK. Therefore, ASFV-G-∆I177L/∆EP402R is a novel, safe and efficacious candidate with potential to be used as an antigenically DIVA vaccine.

Ethical argument for establishing good manufacturing practice for phage therapy in the UK.

Antimicrobial resistance (AMR) poses an increasing threat to patient care and population health and there is a growing need for novel therapies to tackle AMR. Bacteriophage (phage) therapy is a re-emerging antimicrobial strategy with the potential to transform how bacterial infections are treated in patients and populations. Currently, in the UK, phages can be used as unlicensed medicinal products on a 'named-patient' basis. We make an ethical case for why it is crucially important for the UK to invest in Good Manufacturing Practice (GMP) for both ongoing unlicensed and future licensed phage therapy. Access to phages produced to GMP (GMP phages) will ensure effective patient care and better outcomes as well as health systems benefits. The UK also has the potential to become a global leader in the timely and cost-efficient manufacturing and supply of a therapy that meets internationally recognised standards.

Phage Therapy for Diabetic Foot Infection: A Case Series.

PURPOSE: Infected diabetic foot ulcers can be difficult to treat and, despite appropriate antibiotic therapy, some diabetic foot infections (DFIs) require amputation. Bacteriophages (phages) are viruses that infect and kill bacteria. Phage therapy has been repeatedly used to successfully treat DFIs and other chronic wounds. METHODS: This article reports the provision of topical adjunctive anti-staphylococcal phage therapy to 10 patients with DFI at high risk of amputation at two UK hospitals as part of clinical care; tolerability and efficacy were clinically assessed. FINDINGS: The opinion of the experienced clinical teams caring for these patients was that 9 of the 10 patients appeared to benefit from adjunctive phage therapy. No adverse effects were reported by clinicians or patients. In 6 of 10 patients the clinical impression was that phage therapy facilitated clinical resolution of infection and limb salvage. Resolution of soft tissue infection was observed in a 7th patient but unresolved osteomyelitis required amputation. An 8th patient demonstrated eradication of Staphylococcus aureus from a polymicrobial infection and a 9th showed signs of clinical improvement before early cessation of phage therapy due to an unrelated event. One patient, with a weakly susceptible S aureus isolate, had no significant response. IMPLICATIONS: This report describes the largest application of phage therapy in the United Kingdom to date and the first application of phage therapy for DFI in the United Kingdom and offers subjective hints toward impressive tolerability and efficacy. Phage therapy has the potential to transform the prevention and treatment of DFIs.

The Future of Clinical Phage Therapy in the United Kingdom.

Bacteriophage (phage) therapy is a promising alternative antimicrobial strategy with the potential to transform the way bacterial infections are treated. In the United Kingdom, phages are classed as a biological medicine. Although no phages are licensed for UK use, they may be used as unlicensed medicinal products where licensed alternatives cannot meet a patient's clinical needs. In the last 2 years, 12 patients in the UK have received phage therapy, and there is burgeoning clinical interest. Currently, clinical phage provision in the UK is ad hoc and relies upon networking with international sources of phages. The provision of phage therapy in the UK will not progress beyond an increasing number of ad hoc cases until an onshore sustainable and scalable source of well-characterised phages manufactured in accordance with Good Manufacturing Practice (GMP) is established. Here, we present an exciting new collaboration between UK Phage Therapy, the Centre for Phage Research at University of Leicester, CPI, and Fixed Phage. These partners, and others as we develop, will establish sustainable, scalable, and equitable phage therapy provision in the UK. We set out a vision for how phage therapy will be integrated into the NHS and healthcare more broadly, including the complementarity between licensed (cocktail) and unlicensed (personalised) phage preparations. Key elements of phage therapy infrastructure in the UK will be GMP phage manufacturing, a national phage library, and a national clinical phage centre. Together, this infrastructure will support NHS microbiology departments to develop and oversee phage therapy provision across the UK. As it will take time to deliver this, we also describe considerations for clinicians seeking to use unlicensed phage therapy in the interim. In summary, this review sets out a roadmap for the delivery of clinical phage therapy to the UK, the benefits of which we hope will reverberate for patients for decades to come.

Retinoic Acid Signalling in the Pineal Gland Is Conserved across Mammalian Species and Its Transcriptional Activity Is Inhibited by Melatonin.

The pineal gland is integral to the circadian timing system due to its role in nightly melatonin production. Retinoic acid (RA) is a potent regulator of gene transcription and has previously been found to exhibit diurnal changes in synthesis and signalling in the rat pineal gland. This study investigated the potential for the interaction of these two systems. PCR was used to study gene expression in mouse and human pineal glands, ex-vivo organotypic cultured rat pineal gland and cell lines. The mouse and human pineal glands were both found to express the necessary components required for RA signalling. RA influences the circadian clock in the brain, therefore the short-term effect of RA on clock gene expression was determined in ex vivo rat pineal glands but was not found to rapidly regulate Per1, Per2, Bmal1, or Cry1. The interaction between RA and melatonin was also investigated and, unexpectedly, melatonin was found to suppress the induction of gene transcription by RA. This study demonstrates that pineal expression of the RA signalling system is conserved across mammalian species. There is no short-term regulation of the circadian clock but an inhibitory effect of melatonin on RA transcriptional activity was demonstrated, suggesting that there may be functional cross-talk between these systems.

The Statewide Epidemiology of Mucormycosis Among Trauma Patients in Florida.

OBJECTIVES: Mucormycosis is a rare angioinvasive infection caused by filamentous fungi with a high lethality among the immunocompromised. In healthy people, the innate immune system is sufficient to prevent infection. The exception to this is deep tissue exposure seen during trauma. The purpose of this study is to evaluate the epidemiology of mucormycosis using a statewide population-based data set. METHODS: This is a retrospective cohort study of all hospital admissions for mucormycosis within the state of Florida from 1997 through the beginning of 2020. A distribution map was created to evaluate for geographic variation. Botanical growth zones, based on plant hardiness, used by state environmental agencies and landscapers were also used to detect possible patterns based on climate conditions throughout Florida. A multivariable regression analysis was performed to account for confounders and limit bias. RESULTS: A total of 1190 patients were identified for mucormycosis infection. Only 86 of these patients were admitted for trauma. Cutaneous infections were more prevalent among trauma patients while non-trauma patients had more pulmonary infections (P = .04). Trauma patients with infection tended to be younger and less likely to suffer from comorbidities such as immunosuppression (36% vs 46%, P = .07) and diabetes (22.1% vs 47.1%, P ≤ .0001) as compared to their non-trauma counterparts. Mortality was similar with 17.8% for non-trauma patients and 15.1% for traumatized patients (AOR .80 [.42, 1.52]). Length of stay was longer for trauma patients (37.3 vs 23.0, P < .0001). Infections were less prominent in plant hardiness Zone 9 and Zone 10 as compared to Zone 8 (AOR .71 [.61, .82]; AOR .54 [.46, .64], respectively). CONCLUSION: Trauma patients who develop infection from mucormycosis are at high risk of death despite being a younger and healthier population. Mucormycosis infections were primarily soft tissue based among trauma patients. These infections are more prevalent in colder regions within Florida.

Increased Mortality in Hip Fracture Patients With Aortic Stenosis and Pulmonary Hypertension Compared to Aortic Stenosis Alone.

INTRODUCTION: Hip fractures are one of the most common traumatic injuries in the United States, secondary to an aging population. Multiple comorbidities are found in patients who present to trauma centers (TCs) with isolated hip fractures (IHFs) including significant cardiac disease. Aortic stenosis (AS) among these patients has been recently shown to increase mortality. However, factors leading to death from AS are unknown. We hypothesize that pulmonary hypertension (PH) is a significant mechanism of death among IHF patients with AS. METHODS: This is a multicenter retrospective cohort study examining IHF patients treated at Level I and II TCs within a large hospital system from 2015 to 2019. Patients who had IHFs and AS were compared to those who had IHFs, AS, and PH. Multivariable logistic regression was used to risk adjust by age, race, insurance status, and comorbidities. The primary outcome was inpatient mortality. The secondary outcomes were hospital-acquired complications. RESULTS: A total of 1388 IHF patients with AS were included in the study. Eleven percent of these patients also had PH. The crude mortality rate was higher if IHF patients had both AS and PH compared to IHF with AS alone (9% vs 3.7%, P-value .003). After risk adjustment, a higher risk of mortality was still significant (aOR 2.56 [95% CI 1.28, 5.11]). In addition, IHF patients with both AS and PH had higher complication rates; the exposure group had higher percentage of pulmonary embolism (1.4% vs .2%, adjusted P-value .03), new-onset congestive heart failure (4.1% vs 1%, adjusted P-value .01), and sepsis/septicemia (3.5% vs 1.4%, adjusted P-value .05). CONCLUSION: In patients with IHFs, PH and AS increase the likelihood of inpatient mortality by 2.5 times compared to AS alone. Pulmonary hypertension among IHF patients with AS is an important risk factor to identify in the preoperative period. Early identification may lead to better perioperative management and counseling of patients at higher risk of complications.

Frailty Score as a Predictor of Outcomes in Geriatric Patients with Isolated Hip Fractures.

BACKGROUND: Isolated hip fractures (IHFs) are a cause of morbidity and mortality in the geriatric population aged >65 years. Frailty has been identified as a determinant for patient outcomes in other surgical specialties. The purpose of this study is to determine if frailty severity is a predictor of outcomes in IHF in the geriatric population. METHODS: This is a retrospective study in a state and ACS Level 2 trauma center. Patients with IHF were reviewed between January 2018 and January 2020. Primary outcome was in-patient mortality. Secondary outcomes include perioperative outcome measures such as UTI, HCAP, DVT, readmission, length of stay, ICU length of stay, nutritional status, and discharge destination. Patients were stratified into mild (1-2), moderate (3-5), and severe (5-7) frailty using the Rockwood Frailty Score (RFS). Clinical characteristics and outcomes were analyzed. RESULTS: We identified 470 patients with IHF who were stratified by mild (N=316), moderate (N-123), and severe (N=31) frailty. Frailty worsened with increasing age (P < .0001). Those who were less frail were more likely discharged home (P < .04). Severely frail patients were more likely discharged to hospice (P < .01). Severely frail patients also were more likely to develop DVT (P < .04) and have poorer nutritional status (P < .02). There were no differences among groups for in-patient mortality. CONCLUSION: Severely frail patients are more likely to be malnourished at baseline and be discharged to hospice care. The RFS is a reliable objective tool to identify high-risk patients and guide goals of care discussion for operative intervention in isolated traumatic hip fractures.

SARS-CoV-2 Serology and Self-Reported Infection Among Adults - National Health and Nutrition Examination Survey, United States, August 2021-May 2022.

CDC COVID-19 surveillance systems monitor SARS-CoV-2 antibody prevalence to collect information about asymptomatic, undiagnosed, and unreported disease using national convenience samples of blood donor data from commercial laboratories (1,2). However, nonrandom sampling of data from these systems could affect prevalence estimates (1-3). The National Health and Nutrition Examination Survey (NHANES) collects SARS-CoV-2 serology data among a sample of the general U.S. civilian population (4). In addition, NHANES collects self-reported COVID-19 vaccination and disease history, and its statistical sampling design is not based on health care access or blood donation. Therefore, NHANES data can be used to better quantify asymptomatic SARS-CoV-2 infection prevalence and seropositivity attained through infection without vaccination. Preliminary NHANES 2021-2022 results indicated that 41.6% of adults aged ≥18 years had serology indicative of past infection and that 43.7% of these adults, including 57.1% of non-Hispanic Black or African American (Black) adults, reported never having had COVID-19, possibly representing asymptomatic infection. In addition, 25.5% of adults whose serology indicated past infection reported never having received COVID-19 vaccination. Prevalences of seropositivity in the absence of vaccination were higher among younger adults and Black adults, reflecting the lower observed vaccination rates among these groups (5). These findings raise health equity concerns given the disparities observed in SARS-CoV-2 infection and COVID-19 vaccination. Results from NHANES 2021-2022 can guide ongoing efforts to achieve vaccine equity in COVID-19 primary vaccination series and booster dose coverage.

First-in-human phase I/II, open-label study of the anti-OX40 agonist INCAGN01949 in patients with advanced solid tumors.

BACKGROUND: OX40 is a costimulatory receptor upregulated on antigen-activated T cells and constitutively expressed on regulatory T cells (Tregs). INCAGN01949, a fully human immunoglobulin G1κ anti-OX40 agonist monoclonal antibody, was designed to promote tumor-specific immunity by effector T-cell activation and Fcγ receptor-mediated Treg depletion. This first-in-human study was conducted to determine the safety, tolerability, and preliminary efficacy of INCAGN01949. METHODS: Phase I/II, open-label, non-randomized, dose-escalation and dose-expansion study conducted in patients with advanced or metastatic solid tumors. Patients received INCAGN01949 monotherapy (7-1400 mg) in 14-day cycles while deriving benefit. Safety measures, clinical activity, pharmacokinetics, and pharmacodynamic effects were assessed and summarized with descriptive statistics. RESULTS: Eighty-seven patients were enrolled; most common tumor types were colorectal (17.2%), ovarian (8.0%), and non-small cell lung (6.9%) cancers. Patients received a median three (range 1-9) prior therapies, including immunotherapy in 24 patients (27.6%). Maximum tolerated dose was not reached; one patient (1.1%) receiving 350 mg dose reported dose-limiting toxicity of grade 3 colitis. Treatment-related adverse events were reported in 45 patients (51.7%), with fatigue (16 (18.4%)), rash (6 (6.9%)), and diarrhea (6 (6.9%)) being most frequent. One patient (1.1%) with metastatic gallbladder cancer achieved a partial response (duration of 6.3 months), and 23 patients (26.4%) achieved stable disease (lasting >6 months in one patient). OX40 receptor occupancy was maintained over 90% among all patients receiving doses of ≥200 mg, while no treatment-emergent antidrug antibodies were detected across all dose levels. Pharmacodynamic results demonstrated that treatment with INCAGN01949 did not enhance proliferation or activation of T cells in peripheral blood or reduce circulating Tregs, and analyses of tumor biopsies did not demonstrate any consistent increase in effector T-cell infiltration or function, or decrease in infiltrating Tregs. CONCLUSION: No safety concerns were observed with INCAGN01949 monotherapy in patients with metastatic or advanced solid tumors. However, tumor responses and pharmacodynamic effects on T cells in peripheral blood and post-therapy tumor biopsies were limited. Studies evaluating INCAGN01949 in combination with other therapies are needed to further evaluate the potential of OX40 agonism as a therapeutic approach in patients with advanced solid tumors. TRIAL REGISTRATION NUMBER: NCT02923349.

Comparability of in-person and web screening: Does mode affect what households report?

Household screening is common when information about characteristics of household members is needed for selection of survey respondents. When key characteristics have a low prevalence, or are oversampled, this can result in a large number of sampled households screened, many of which have no persons selected. For in-person surveys this can be inefficient and costly, especially in an environment of declining response. A multimode design using a mail, push-to-web approach is an attractive alternative due to lower cost and high internet penetration. However, little is known about the comparable data quality properties between in-person and web modes. While in-person screening is considered a gold standard approach, respondents may fail to report household members and interviewers may unintentionally screen out reluctant respondents. Similarly, those self-responding sometimes fail to report unrelated household members or young children. In this study we compared in-person and web screening in the National Health and Nutrition Examination Survey. Households were randomly selected to complete a self-administered web screener and subsequently be screened by an interviewer during an in-person visit. We report on the comparability of household characteristics between modes to determine if web screening provides data equivalent to in-person screening. We examine time between the web and in-person screening to see if true change can account for differences. In the presence of conflicting data, we examine selection criteria based on the screening responses to see how inaccuracies affect selection status, or if inaccuracies or person omissions are systematically related to a specific mode. Approximately 93% (80/86) of households agreed on selection status between the web and in-person modes. Household composition matched fully for 84% (72/86) of households. These results indicate that web screening is a viable option enumerating households in population surveys.

Undertriage of Geriatric Trauma Patients in Florida.

INTRODUCTION: Elderly undertriage rates are estimated up to 55% in the United States. This study examined risk factors for undertriage among hospitalized trauma patients in a state with high volumes of geriatric trauma patients. MATERIALS AND METHODS: This is a population-based retrospective cohort study of 62,557 patients admitted to Florida hospitals between 2016 and 2018 from the Agency for Healthcare Administration database. Severely injured trauma patients were defined by American College of Surgeons definitions and an International Classification of Disease Injury Severity Score <0.85. Undertriage was defined as definitive care of these severely injured patients at any Florida hospital other than a state-designated trauma center (TC). Univariate analyses were used to identify risk factors associated with inpatient mortality and undertriage. Multiple variable regression was used to estimate risk-adjusted odds of mortality after admission to either a designated or nondesignated TC. RESULTS: Undertriaged patients were more likely to have isolated traumatic brain injuries, lower International Classification of Disease Injury Severity Scores, multiple comorbidities, and older age. Trauma patients aged 65 and older were more than twice as likely to be undertriaged (34% versus 15.7%, P < 0.0001). Undertriaged patients of all ages were also more likely to suffer from pneumonia, urinary tract infection, arrhythmias, and sepsis. After risk adjustment, severely injured trauma patients admitted to non-TC were also more likely to be at risk for mortality (adjusted odds ratio, 1.27; 95% confidence interval, 1.17-1.38). CONCLUSIONS: Age and multiple comorbidities are significant predictors of mortality among undertriage of trauma patients. As a result, trauma triage guidelines should account for high-risk geriatric trauma patients who would benefit from definitive treatment at designated TCs.

Expanding beaver pond distribution in Arctic Alaska, 1949 to 2019.

Beavers were not previously recognized as an Arctic species, and their engineering in the tundra is considered negligible. Recent findings suggest that beavers have moved into Arctic tundra regions and are controlling surface water dynamics, which strongly influence permafrost and landscape stability. Here we use 70 years of satellite images and aerial photography to show the scale and magnitude of northwestward beaver expansion in Alaska, indicated by the construction of over 10,000 beaver ponds in the Arctic tundra. The number of beaver ponds doubled in most areas between ~ 2003 and ~ 2017. Earlier stages of beaver engineering are evident in ~ 1980 imagery, and there is no evidence of beaver engineering in ~ 1952 imagery, consistent with observations from Indigenous communities describing the influx of beavers over the period. Rapidly expanding beaver engineering has created a tundra disturbance regime that appears to be thawing permafrost and exacerbating the effects of climate change.

National Health and Nutrition Examination Survey, 2017-March 2020 Prepandemic File: Sample Design, Estimation, and Analytic Guidelines.

Objectives This report describes the creation of the NHANES 2017-March 2020 prepandemic data files, including the selection of the appropriate NHANES sample design (2015-2018) to create sample weights and variance units for public-use data files. Additionally, the development of a factor applied to the primary sampling units to adjust the 2017-March 2020 data to fit the NHANES 2015-2018 sample design is described. Analyses to assess representativeness of the target population were performed, and a simulation to replicate the impact of interrupted data collection using earlier NHANES cycles was undertaken. Analytic guidance specific to use for prepandemic data files is also included. .

Safety and Efficacy of Ruxolitinib in Patients with Myelofibrosis and Low Platelet Counts (50 - 100 × 109/L): Final Analysis of an Open-Label Phase 2 Study.

INTRODUCTION: Treatment options in patients with myelofibrosis (MF) presenting with thrombocytopenia are limited. Final results of the phase 2 study (NCT01348490) of ruxolitinib in patients with MF and low baseline platelet counts (50 - 100 × 109/L) are reported. PATIENTS AND METHODS: Patients received ruxolitinib 5 mg twice daily (BID), with optional up-titration to a maximum of 15 mg BID, provided platelet count remained ≥40 × 109/L. Assessments included spleen volume and length, Total Symptom Score (TSS), quality of life, and safety. RESULTS: Of 66 patients, 52 (78.8%) completed the first 24 weeks of treatment. Median (range) percentage change from baseline in spleen volume and TSS (coprimary endpoints) were -20.5% (-55.8% to 38.5%, n=51) and -39.8% (-98.6% to 226.4%, n=53), respectively; greatest median reductions were in the 10 mg BID final titrated dose group. Of patients achieving ≥35% or ≥10% reduction in spleen volume, 8/11 (72.7%) and 21/34 (61.8%), respectively, were in the 10 mg BID final titrated dose group. Thirty-seven of 65 patients (56.9%) had ≥20% improvement in TSS, and 35/66 patients (53.0%) were Patient Global Impression of Change responders. Treatment-emergent adverse events led to dose interruption in 17/66 patients (25.8%), most commonly thrombocytopenia (n=3). CONCLUSION: A starting dose of ruxolitinib 5 mg BID with gradual up-titration and dose optimization based on hematologic parameters and response was efficacious and generally well-tolerated in patients with MF and low platelet counts. Median improvement in spleen volume and symptoms was greatest for patients receiving ruxolitinib 10 mg BID.

LAMP-5 is an essential inflammatory-signaling regulator and novel immunotherapy target for mixed lineage leukemia-rearranged acute leukemia.

Although great advances have been made in understanding the pathobiology of mixed lineage leukemia-rearranged (MLL-r) leukemias, therapies for this leukemia have remained limited, and clinical outcomes remain bleak. In order to identify novel targets for immunotherapy treatments, we compiled a lineage-independent MLL-r leukemia gene signature using publicly available data sets. Data from large leukemia repositories were filtered through the in silico human surfaceome, providing a list of highly predicted cell surface proteins overexpressed in MLL-r leukemias. LAMP5, a lysosomal associated membrane protein, is expressed highly and specifically in MLL-r leukemia. We found that LAMP5 is a direct target of the oncogenic MLL-fusion protein. LAMP5 depletion significantly inhibited leukemia cell growth in vitro and in vivo. Functional studies showed that LAMP-5 is a novel modulator of innate-immune pathways in MLL-r leukemias. Downregulation of LAMP5 led to inhibition of NF-kB signaling and increased activation of type-1 interferon signaling downstream of Toll-like receptor/interleukin 1 receptor activation. These effects were attributable to the critical role of LAMP-5 in transferring the signal flux from interferon signaling endosomes to pro-inflammatory signaling endosomes. Depletion of IRF7 was able to partially rescue the cell growth inhibition upon LAMP5 downregulation. Lastly, LAMP-5 was readily detected on the surface of MLL-r leukemia cells. Targeting surface LAMP-5 using an antibody-drug conjugate leads to significant cell viability decrease specifically in MLL-r leukemias. Overall, based on the limited expression throughout human tissues, we postulate that LAMP-5 could potentially serve as an immunotherapeutic target with a wide therapeutic window to treat MLL-r leukemias.

Comparison of Delivery Methods in Phage Therapy against Flavobacterium columnare Infections in Rainbow Trout.

Viruses of bacteria, bacteriophages, specifically infect their bacterial hosts with minimal effects on the surrounding microbiota. They have the potential to be used in the prevention and treatment of bacterial infections, including in the field of food production. In aquaculture settings, disease-causing bacteria are often transmitted through the water body, providing several applications for phage-based targeting of pathogens, in the rearing environment, and in the fish. We tested delivery of phages by different methods (via baths, in phage-coated material, and via oral delivery in feed) to prevent and treat Flavobacterium columnare infections in rainbow trout fry using three phages (FCOV-S1, FCOV-F2, and FCL-2) and their hosts (FCO-S1, FCO-F2, and B185, respectively). Bath treatments given before bacterial infection and at the onset of the disease symptoms were the most efficient way to prevent F. columnare infections in rainbow trout, possibly due to the external nature of the disease. In a flow-through system, the presence of phage-coated plastic sheets delayed the onset of the disease. The oral administration of phages first increased disease progression, although total mortality was lower at the end of the experiment. When analysed for shelf-life, phage titers remained highest when maintained in bacterial culture media and in sterile lake water. Our results show that successful phage therapy treatment in the aquaculture setting requires optimisation of phage delivery methods in vivo.

Formulations for Bacteriophage Therapy and the Potential Uses of Immobilization.

The emergence of antibiotic-resistant pathogens is becoming increasingly problematic in the treatment of bacterial diseases. This has led to bacteriophages receiving increased attention as an alternative form of treatment. Phages are effective at targeting and killing bacterial strains of interest and have yielded encouraging results when administered as part of a tailored treatment to severely ill patients as a last resort. Despite this, success in clinical trials has not always been as forthcoming, with several high-profile trials failing to demonstrate the efficacy of phage preparations in curing diseases of interest. Whilst this may be in part due to reasons surrounding poor phage selection and a lack of understanding of the underlying disease, there is growing consensus that future success in clinical trials will depend on effective delivery of phage therapeutics to the area of infection. This can be achieved using bacteriophage formulations instead of purely liquid preparations. Several encapsulation-based strategies can be applied to produce phage formulations and encouraging results have been observed with respect to efficacy as well as long term phage stability. Immobilization-based approaches have generally been neglected for the production of phage therapeutics but could also offer a viable alternative.