Objectives: To understand SARS-Co-V-2 infection and transmission in UK nursing homes in order to develop preventive strategies for protecting the frail elderly residents. Methods: An outbreak investigation involving 394 residents and 70 staff, was carried out in 4 nursing homes affected by COVID-19 outbreaks in central London. Two point-prevalence surveys were performed one week apart where residents underwent SARS-CoV-2 testing and had relevant symptoms documented. Asymptomatic staff from three of the four homes were also offered SARS-CoV-2 testing. Results: Overall, 26% (95% CI 22-31) of residents died over the two-month period. All-cause mortality increased by 203% (95% CI 70-336) compared with previous years. Systematic testing identified 40% (95% CI 35-46) of residents as positive for SARS-CoV-2, and of these 43% (95% CI 34-52) were asymptomatic and 18% (95% CI 11-24) had only atypical symptoms; 4% (95% CI −1 to 9) of asymptomatic staff also tested positive. Conclusions: The SARS-CoV-2 outbreak in four UK nursing homes was associated with very high infection and mortality rates. Many residents developed either atypical or had no discernible symptoms. A number of asymptomatic staff members also tested positive, suggesting a role for regular screening of both residents and staff in mitigating future outbreaks.

Objectives: To understand SARS-Co-V-2 infection and transmission in UK nursing homes in order to develop preventive strategies for protecting the frail elderly residents. Design: An outbreak investigation. Setting: 4 nursing homes affected by COVID-19 outbreaks in central London. Participants: 394 residents and 70 staff in nursing homes. Interventions: Two point-prevalence surveys one week apart where residents underwent SARS-CoV-2 testing and had relevant symptoms documented. Asymptomatic staff from three of the four homes were also offered SARS-CoV-2 testing. Main outcome measures: All-cause mortality, and mortality attributed to COVID-19 on death certificates. Prevalence of SARS-CoV-2 infection and symptoms in residents and staff. Results: Overall, 26% (95% confidence interval 22 to 31) of residents died over the two-month period. All-cause mortality increased by 203% (95% CI 70 to 336). Systematic testing identified 40% (95% CI 35 to 46) of residents, of whom 43% (95% CI 34 to 52) were asymptomatic and 18% (95% CI 11 to 24) had atypical symptoms, as well as 4% (95% CI -1 to 9) of asymptomatic staff who tested positive for SARS-CoV-2. Conclusions: The SARS-CoV-2 outbreak was associated with a very high mortality rate in residents of nursing homes. Systematic testing of all residents and a representative sample of staff identified high rates of SARS-CoV-2 positivity across the four nursing homes, highlighting a potential for regular screening to prevent future outbreaks.

Synthetic biology designed cell-free biosensors are a promising new tool for the detection of clinically relevant biomarkers in infectious diseases. Here, we report that a modular DNA-encoded biosensor in cell-free protein expression systems can be used to measure a bacterial biomarker of Pseudomonas aeruginosa infection from human sputum samples. By optimizing the cell-free system and sample extraction, we demonstrate that the quorum sensing molecule 3-oxo-C12-HSL in sputum samples from cystic fibrosis lungs can be quantitatively measured at nanomolar levels using our cell-free biosensor system, and is comparable to LC-MS measurements of the same samples. This study further illustrates the potential of modular cell-free biosensors as rapid, low-cost detection assays that can inform clinical practice.

Pseudomonas aeruginosa is a remarkably versatile environmental bacterium with an extraordinary capacity to infect the cystic fibrosis (CF) lung. Infection with P. aeruginosa occurs early, and although eradication can be achieved following early detection, chronic infection occurs in over 60% of adults with CF. Chronic infection is associated with accelerated disease progression and increased mortality. Extensive research has revealed complex mechanisms by which P. aeruginosa adapts to and persists within the CF airway. Yet knowledge gaps remain, and prevention and treatment strategies are limited by the lack of sensitive detection methods and by a narrow armoury of antibiotics. Further developments in this field are urgently needed in order to improve morbidity and mortality in people with CF. Here, we summarize current knowledge of pathophysiological mechanisms underlying P. aeruginosa infection in CF. Established treatments are discussed, and an overview is offered of novel detection methods and therapeutic strategies in development.

Pseudomonas aeruginosa opportunistically infects the airways of patients with cystic fibrosis and causes significant morbidity and mortality. Initial infection can often be eradicated though requires prompt detection and adequate treatment. Intermittent and then chronic infection occurs in the majority of patients. Better detection of P. aeruginosa infection using biomarkers may enable more successful eradication before chronic infection is established. In chronic infection P. aeruginosa adapts to avoid immune clearance and resist antibiotics via efflux pumps, β-lactamase expression, reduced porins and switching to a biofilm lifestyle. The optimal treatment strategies for P. aeruginosa infection are still being established, and new antibiotic formulations such as liposomal amikacin, fosfomycin in combination with tobramycin and inhaled levofloxacin are being explored. Novel agents such as the alginate oligosaccharide OligoG, cysteamine, bacteriophage, nitric oxide, garlic oil and gallium may be useful as anti-pseudomonal strategies, and immunotherapy to prevent infection may have a role in the future. New treatments that target the primary defect in cystic fibrosis, recently licensed for use, have been associated with a fall in P. aeruginosa infection prevalence. Understanding the mechanisms for this could add further strategies for treating P. aeruginosa in future.

We have shown that a lentiviral vector (rSIV.F/HN) pseudotyped with the F and HN proteins from Sendai virus generates high levels of intracellular proteins after lung transduction. Here, we evaluate the use of rSIV.F/HN for production of secreted proteins. We assessed whether rSIV.F/HN transduction of the lung generates therapeutically relevant levels of secreted proteins in the lung and systemic circulation using human α1-anti-trypsin (hAAT) and factor VIII (hFVIII) as exemplars. Sedated mice were transduced with rSIV.F/HN carrying either the secreted reporter gene Gaussia luciferase or the hAAT or hFVIII cDNAs by nasal sniffing. rSIV.F/HN-hAAT transduction lead to therapeutically relevant hAAT levels (70 μg/ml) in epithelial lining fluid, with stable expression persisting for at least 19 months from a single application. Secreted proteins produced in the lung were released into the circulation and stable expression was detectable in blood. The levels of hFVIII in murine blood approached therapeutically relevant targets. rSIV.F/HN was also able to produce secreted hAAT and hFVIII in transduced human primary airway cells. rSIV.F/HN transduction of the murine lungs leads to long-lasting and therapeutically relevant levels of secreted proteins in the lung and systemic circulation. These data broaden the use of this vector platform for a large range of disease indications.

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Introduction and objectivesA protease/anti-protease imbalance is a characteristic feature of inflammatory lung diseases such as cystic fibrosis (CF) and alpha-1-antitrypsin deficiency related emphysema. A recent trial of alpha-1-antitrypsin (hAAT) enzyme replacement therapy (ERT) suggested that hAAT can slow the progression of lung density loss in alpha-1-antitrypsin deficiency (Chapman et al, Lancet 2015). However, the results are modest and ERT is expensive, so gene therapy may be a more appropriate treatment strategy.The UK Cystic Fibrosis Gene Therapy Consortium has pseudotyped a simian immunodeficiency viral vector with the Sendai virus F and HN proteins (rSIV. F/HN) for efficient transduction of airway epithelial cells.ResultsMice were transduced with rSIV. F/HN-hAAT (1.4e8 TU/mouse) by nasal instillation and culled 10 days post-transduction. hAAT levels in lung tissue homogenate and epithelial lining fluid (ELF) were 3 logs above controls (p < 0.05), and hAAT concentration in ELF was 92 ± 28 μg/ml, similar to the therapeutic hAAT level in ELF of 70 μg/ml (Figure 1). For comparison, transfection of mouse lung with cationic lipid GL67A, used in the recent Phase IIb trial of non-viral gene therapy for cystic fibrosis, complexed to plasmids carrying hAAT only led to 0.4 ± 0.1 μg/ml in ELF.Abstract S127 Figure 1Expression of hAAT in epithelial lining fluid following treatment with rSIV. F/HN-hAAT. Mice were given between 2e7 and 1.4e8 TU virus and sacrificed 7–10 days post-treatmentA neutrophil elastase (NE) activity assay showed that the recombinant hAAT successfully neutralised NE activity (p < 0.05). In a separate experiment, mice were treated with a single dose of rSIV. F/HN-hAAT (4e7 TU/mouse) and quantification of hAAT one year post-transduction showed that expression was stable over this period. Here, we also demonstrate for the first time that rSIV. F/HN transduction of lung generates significant (p < 0.05) levels of recombinant hAAT protein in serum.ConclusionIn conclusion, rSIV. F/HN produces therapeutically relevant and long-lasting levels of hAAT in murine lung and may offer advantages over enzyme replacement therapy. In addition, we showed that hAAT escapes from the lung into the circulation which may be relevant for a range of diseases including diabetes and graft vs. host disease.Reference1 Chapman KR, Burdon JG, Piitulainen E et al. Intravenous augmentation treatment and lung density in severe α1 antitrypsin deficiency (RAPID): a randomised, double-blind, placebo-controlled trial. Lancet. 2015;386:360–8