Differential role of sphingomyelin in influenza virus, rhinovirus and SARS-CoV-2 infection of Calu-3 cells

Host cell lipids play a pivotal role in the pathogenesis of respiratory virus infection. However, a direct comparison of the lipidomic profile of influenza virus and rhinovirus infections is lacking. In this study, we first compared the lipid profile of influenza virus and rhinovirus infection in a bronchial epithelial cell line. Most lipid features were downregulated for both influenza virus and rhinovirus, especially for the sphingomyelin features. Pathway analysis showed that sphingolipid metabolism was the most perturbed pathway. Functional study showed that bacterial sphingomyelinase suppressed influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication, but promoted rhinovirus replication. These findings suggest that sphingomyelin pathway can be a potential target for antiviral therapy, but should be carefully evaluated as it has opposite effects on different respiratory viruses. Furthermore, the differential effect of sphingomyelinase on rhinovirus and influenza virus may explain the interference between rhinovirus and influenza virus infection.

Management of peri-prosthetic joint infection and severe bone loss after total hip arthroplasty using a long-stemmed cemented custom-made articulating spacer (CUMARS)

Background

There is little evidence on techniques for management of peri-prosthetic infection (PJI) in the context of severe proximal femoral bone loss. Custom-made articulating spacers (CUMARS) utilising cemented femoral stems as spacers was described providing better bone support and longer survival compared to conventional articulating spacers. We retrospectively report our experience managing PJI by adaptation of this technique using long cemented femoral stems where bone loss precludes use of standard stems.

Methods

Patients undergoing 1st stage revision for infected primary and revision THA using a cemented long stem (> 205 mm) and standard all-polyethylene acetabulum between 2011 and 2018 were identified. After excluding other causes of revision (fractures or aseptic loosening), Twenty-one patients remained out of total 721 revisions. Medical records were assessed for demographics, initial microbiological and operative treatment, complications, eradication of infection and subsequent operations. 2nd stage revision was undertaken in the presence of pain or subsidence.

Results

Twenty-one patients underwent 1st stage revision with a cemented long femoral stem. Mean follow up was 3.9 years (range 1.7–7.2). Infection was eradicated in 15 (71.4%) patients. Two patients (9.5%) required repeat 1st stage and subsequently cleared their infection. Three patients (14.3%) had chronic infection and are on long term suppressive antibiotics. One patient (4.8%) was lost to follow up before 2 years. Complications occurred in seven patients (33%) during or after 1st stage revision. Where infection was cleared, 2nd stage revision was undertaken in 12 patients (76.5%) at average of 9 months post 1st stage. Five (23.8%) CUMARS constructs remained in-situ at an average of 3.8 years post-op (range 2.6–5.1).

Conclusions

Our technique can be used in the most taxing of reconstructive scenarios allowing mobility, local antibiotic delivery, maintenance of leg length and preserves bone and soft tissue, factors not afforded by alternative spacer options.

The effect of the COVID-19 lockdown on the epidemiology of hip fractures in the elderly: a multicentre cohort study

INTRODUCTION

The COVID-19 pandemic presented extraordinary challenges to the UK healthcare system. This study aimed to assess the impact of the COVID-19 lockdown on the epidemiology, treatment pathways and 30-day mortality rates of hip fractures. Outcomes of COVID-19 positive patients were compared against those who tested negative.

METHODS

An observational, retrospective, multicentre study was conducted across six hospitals in the South East of England. Data were retrieved from the National Hip Fracture Database and electronic medical records. Data was collected for the strictest UK lockdown period (period B=23 March 2020-11 May 2020), and the corresponding period in 2019 (period A).

RESULTS

A total of 386 patients were admitted during period A, whereas 381 were admitted during period B. Despite the suspension of the 'Best Practice Tariff' during period B, time to surgery, time to orthogeriatric assessment, and 30-day mortality were similar between period A and B. The length of inpatient stay was significantly shorter during period B (11.5 days vs 17.0 days, p<0.001). Comparison of COVID-19 positive and negative patients during period B demonstrated that a positive test was associated with a significantly higher rate of 30-day mortality (53.6% vs 6.7%), surgical delay >36h (46.4% vs 30.8%, p=0.049), and increased length of inpatient stay (15.8 vs 11.7 days, p=0.015).

CONCLUSIONS

The COVID-19 lockdown did not alter the epidemiology of hip fractures. A substantially higher mortality rate was observed among patients with a COVID-19 positive test. These findings should be taken into consideration by the healthcare policymakers while formulating contingency plans for a potential 'second wave'.

Thirty-day mortality following surgical management of hip fractures during the COVID-19 pandemic: findings from a prospective multi-centre UK study

PURPOSE

Thirty-day mortality of patients with hip fracture is well researched and predictive; validated scoring tools have been developed (Nottingham Hip Fracture Score, NHFS). COVID-19 has significantly greater mortality in the elderly and comorbid patients which includes hip fracture patients. Non-operative treatment is not appropriate due to significantly higher mortality, and therefore, these patients are often exposed to COVID-19 in the peri-operative period. What is unclear is the effect of concomitant COVID-19 infection in these patients.

METHODS

A multicentre prospective study across ten sites in the United Kingdom (responsible for 7% of hip fracture patients per annum in the UK). Demographic and background information were collected by independent chart review. Data on surgical factors included American Society of Anesthesiologists (ASA) score, time to theatre, Nottingham Hip fracture score (NHFS) and classification of fracture were also collected between 1st March 2020 and 30th April 2020 with a matched cohort from the same period in 2019.

RESULTS

Actual and expected 30-day mortality was found to be significantly higher than expected for 2020 COVID-19 positive patients (RR 3.00 95% CI 1.57-5.75, p < 0.001), with 30 observed deaths compared against the 10 expected from NHFS risk stratification.

CONCLUSION

COVID-19 infection appears to be an independent risk factor for increased mortality in hip fracture patients. Whilst non-operative management of these fractures is not suggested due to the documented increased risks and mortality, this study provides evidence to the emerging literature of the severity of COVID-19 infection in surgical patients and the potential impact of COVID-19 on elective surgical patients in the peri-operative period.

Factors affecting stability and infectivity of SARS-CoV-2

BACKGROUND

In late 2019, a novel human coronavirus - severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) - emerged in Wuhan, China. This virus has caused a global pandemic involving more than 200 countries. SARS-CoV-2 is highly adapted to humans and readily transmits from person-to-person.

AIM

To investigate the infectivity of SARS-CoV-2 under various environmental and pH conditions. The efficacies of various laboratory virus inactivation methods and home disinfectants against SARS-CoV-2 were investigated.

METHODS

The residual virus in dried form or in solution was titrated on to Vero E6 cells on days 0, 1, 3, 5 and 7 after incubation at different temperatures. Viral viability was determined after treatment with various disinfectants and pH solutions at room temperature (20-25^oC).

FINDINGS

SARS-CoV-2 was able to retain viability for 3-5 days in dried form or 7 days in solution at room temperature. SARS-CoV-2 could be detected under a wide range of pH conditions from pH 4 to pH 11 for several days, and for 1-2 days in stool at room temperature but lost 5 logs of infectivity. A variety of commonly used disinfectants and laboratory inactivation procedures were found to reduce viral viability effectively.

CONCLUSION

This study demonstrated the stability of SARS-CoV-2 on environmental surfaces, and raises the possibility of faecal-oral transmission. Commonly used fixatives, nucleic acid extraction methods and heat inactivation were found to reduce viral infectivity significantly, which could ensure hospital and laboratory safety during the SARS-CoV-2 pandemic.

Neurodegeneration and Motor Deficits in the Absence of Astrogliosis upon Transgenic Mutant TDP-43 Expression in Mature Mice

Amyotrophic lateral sclerosis is a rapidly progressing and fatal disease characterized by muscular atrophy due to loss of upper and lower motor neurons. Pathogenic mutations in the TARDBP gene encoding TAR DNA binding protein-43 (TDP-43) have been identified in familial amyotrophic lateral sclerosis. We have previously reported transgenic mice with neuronal expression of human TDP-43 carrying the pathogenic A315T mutation (iTDP-43^A315T mice) using a tetracycline-controlled inducible promotor system. Constitutive expression of transgenic TDP-43^A315T in the absence of doxycycline resulted in pronounced early-onset and progressive neurodegeneration, and motor and memory deficits. Here, delayed transgene expression of TDP-43^A315T by oral doxycycline treatment of iTDP-43^A315T mice from birth till weaning was analyzed. After doxycycline withdrawal, transgenic TDP-43^A315T expression gradually increased and resulted in cytoplasmic TDP-43, widespread ubiquitination, and cortical and hippocampal atrophy. In addition, these mice developed motor and gait deficits with underlying muscle atrophy, similar to that observed in the constitutive iTDP-43^A315T mice. Surprisingly, in contrast to the constitutive iTDP-43^A315T mice, these mice did not develop astrogliosis. In summary, delayed activation coupled with gradual increase in TDP-43^A315T expression in the central nervous system of mature mice resulted in progressive functional deficits with neuron and muscle loss, but in the absence of a glial response. This suggests that astrocytosis does not contribute to functional deficits and neuronal loss upon TDP-43^A315T expression in mature mice.

Lipidomic Profiling Reveals Significant Perturbations of Intracellular Lipid Homeostasis in Enterovirus-Infected Cells

Enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16) are the most common causes of hand, foot, and mouth disease. Severe EV-A71 and CV-A16 infections may be associated with life-threatening complications. However, the pathogenic mechanisms underlying these severe clinical and pathological features remain incompletely understood. Lipids are known to play critical roles in multiple stages of the virus replication cycle. The specific lipid profile induced upon virus infection is required for optimal virus replication. The perturbations in the host cell lipidomic profiles upon enterovirus infection have not been fully characterized. To this end, we performed ultra-high performance liquid chromatography–electrospray ionization–quadrupole–time of flight-mass spectrometry (UPLC-ESI-Q-TOF-MS)-based lipidomics to characterize the change in host lipidome upon EV-A71 and CV-A16 infections. Our results revealed that 47 lipids within 11 lipid classes were significantly perturbed after EV-A71 and CV-A16 infection. Four polyunsaturated fatty acids (PUFAs), namely, arachidonic acid (AA), docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and eicosapentaenoic acid (EPA), were consistently upregulated upon EV-A71 and CV-A16 infection. Importantly, exogenously supplying three of these four PUFAs, including AA, DHA, and EPA, in cell cultures significantly reduced EV-A71 and CV-A16 replication. Taken together, our results suggested that enteroviruses might specifically modulate the host lipid pathways for optimal virus replication. Excessive exogenous addition of lipids that disrupted this delicate homeostatic state could prevent efficient viral replication. Precise manipulation of the host lipid profile might be a potential host-targeting antiviral strategy for enterovirus infection.

Infection after operative fixation of tibia plateau fractures. A risk factor analysis

INTRODUCTION

Surgical fixation of tibial plateau fractures has been shown to improve long-term functional outcomes, but a major complication is that of postoperative infection which can be deleterious to long-term outcomes. This study aims to assess the impact of common comorbidities on the risk of postoperative infection.

METHOD

A retrospective study of 210 consecutive operatively treated patients, treated at two Level 1 Trauma Centres over a 27-month period was performed. Records were analysed to assess the presence of the study factors; smoking, alcohol intake >13 units/week, diabetes, and BMI > 30. The impact of these factors on infection was assessed with univariate and multivariate analyses.

RESULTS

175 patients were included in the study, 56.6% male with a mean age of 46.9 years (± 18.2 years). Excessive alcohol consumption of >13 units/week was the only significant risk factor for postoperative infection (p = 0.05) on multivariate analysis.

CONCLUSION

This study has identified excessive alcohol consumption as the only independent risk factor for postoperative infection in patients with all types of tibial plateau fracture treated with operative fixation. No relationship between smoking, diabetes nor obesity was found for postoperative infection.

Implementation of screening and management of household contacts of tuberculosis cases in Daru, Papua New Guinea

SETTING

Daru Island, Western Province, Papua New Guinea (PNG).

OBJECTIVE

To describe the implementation of a screening programme for household contacts of tuberculosis (TB) cases residing on Daru Island.

DESIGN

This was a retrospective descriptive study evaluating two periods of implementation: introduction and expansion of a screening programme for household contacts of drug-resistant TB (DR-TB) cases (March 2016 to September 2017), and inclusion of drug-susceptible TB (DS-TB) cases with provision of preventive therapy for eligible contacts between October 2017 and March 2018.

RESULTS

In the first period, the contact screening programme was established and strengthened by increasing coverage over time. There was a large number of contacts (median 8) in each household, and a high uptake of screening. In the second period of evaluation, respectively 412 and 223 contacts of 42 DS-TB and 25 DR-TB index cases were screened. Overall, 156 (24.6%) contacts reported TB-related symptoms and 9 (1.4%) were diagnosed with active TB. All 9 commenced TB treatment: 5 had DS-TB and 4 had DR-TB. Of 82 child contacts of DS-TB cases eligible for preventive therapy, 57 (69.5%) commenced treatment and 45 completed treatment.

CONCLUSION

Community-based household contact screening and management was successfully implemented under programme conditions in this high burden TB and DR-TB setting in PNG.

Successful implementation of bedaquiline for multidrug-resistant TB treatment in remote Papua New Guinea

SETTING

Bedaquiline (BDQ) was introduced in the multi-drug-resistant tuberculosis (MDR-TB) programme in Daru in remote Papua New Guinea in 2015, along with a core package of active drug-safety monitoring (aDSM).

OBJECTIVE

To assess interim results and safety of BDQ for the treatment of MDR-TB from 1 July 2015 to 31 December 2017.

DESIGN

A retrospective cohort analysis of routine programme data.

RESULTS

Of 277 MDR-TB patients, 77 (39%) received BDQ with a total of 8 serious adverse events including 5 (6.5%) deaths, of which 1 (1.3% QTcF prolongation, grade 3) was attributable to BDQ. Of 200 (61%) patients who did not receive BDQ, there were 17 (9%) deaths. Completeness of monitoring for the BDQ group was 90% for >5 electrocardiograms and 79% for ⩾2 cultures. In the interim result indicator analysis at month 6 in the BDQ and non-BDQ groups, there were respectively 0% and 1% lost to follow-up; 6.5% and 8.5% who died; 94% and 91% in care; and 92% and 96% with negative culture among those monitored.

CONCLUSION

Early experience in Daru shows BDQ is safe and feasible to implement with aDSM with good interim effectiveness supporting the rapid adoption and scale-up of the 2019 WHO MDR-TB treatment guidelines in the programme and in similar remote settings.

TB treatment delay associated with drug resistance and admission at Daru General Hospital in Papua New Guinea

SETTING

Daru General Hospital, Daru Island, Papua New Guinea, where high rates of tuberculosis (TB) have been reported. Prompt diagnosis and effective treatment are needed for improving TB outcomes and to prevent nosocomial transmission.

OBJECTIVE

To assess the time to treatment initiation and the risk factors associated with delayed treatment for patients started on TB treatment at Daru General Hospital from January to September 2017.

DESIGN

This was a retrospective cohort study that entailed reviewing the records from treatment, admission, discharge and presumptive TB registers.

RESULTS

The study included 360 patients on TB treatment. The median time from presentation to treatment initiation was 7 days [IQR 3-11]. Treatment was started <7 days for 215 patients (60%); however, only 16.2% commenced treatment <2 days. Risk factors for delayed treatment were diagnosis of TB as an inpatient (OR 2.67, 95% CI 1.35-5.28, P = 0.005) and having drug-resistant TB (OR 2.65, 95% CI 1.5-4.68. P = 0.001).

CONCLUSION

A high proportion of TB patients commenced treatment <7 days. Inpatient status, DR-TB and lack of microbiological confirmation were associated with delays in treatment initiation. We recommend that programmes monitor the time from presentation to treatment initiation, and propose that a period of >3 days from presentation to treatment initiation be considered as delayed treatment initiation.

The emergency response to multidrug-resistant tuberculosis in Daru, Western Province, Papua New Guinea, 2014-2017

SETTING

A response to an outbreak of multidrug-resistant tuberculosis (MDR-TB) on Daru Island, South Fly District (SFD), Western Province, Papua New Guinea (PNG) was implemented by a national emergency response taskforce.

OBJECTIVE

To describe programmatic interventions for TB in SFD and evaluate characteristics of TB case notifications, drug resistance and treatment outcomes.

DESIGN

This was a retrospective cohort study based on routine programmatic data for all patients enrolled on TB treatment at Daru General Hospital from 2014 to 2017.

RESULTS

The response involved high-level political commitment, joint planning, resource mobilisation, community engagement and strengthening TB case detection and treatment. Of 1548 people enrolled on TB treatment, 1208 (78%) had drug-susceptible TB (DS-TB) and 333 (21.5%) had MDR-TB. There was an increase in MDR-TB as a proportion of all TB. Treatment success rates increased over the study period from 55% to 86% for DS-TB, and from 70% to 81% for MDR-TB from 2014 to 2015. The 2014 case notification rate for TB in SFD was 1031/100 000, decreasing to 736/100 000 in 2017.

CONCLUSION

The outbreak was stabilised through the response from the national and provincial governments and international partners. Additional interventions are needed to decrease the TB burden in Daru.

CNS cell type-specific gene profiling of P301S tau transgenic mice identifies genes dysregulated by progressive tau accumulation

The microtubule-associated protein tau undergoes aberrant modification resulting in insoluble brain deposits in various neurodegenerative diseases, including frontotemporal dementia (FTD), progressive supranuclear palsy, and corticobasal degeneration. Tau aggregates can form in different cell types of the central nervous system (CNS) but are most prevalent in neurons. We have previously recapitulated aspects of human FTD in mouse models by overexpressing mutant human tau in CNS neurons, including a P301S tau variant in TAU58/2 mice, characterized by early-onset and progressive behavioral deficits and FTD-like neuropathology. The molecular mechanisms underlying the functional deficits of TAU58/2 mice remain mostly elusive. Here, we employed functional genomics (i.e. RNAseq) to determine differentially expressed genes in young and aged TAU58/2 mice to identify alterations in cellular processes that may contribute to neuropathy. We identified genes in cortical brain samples differentially regulated between young and old TAU58/2 mice relative to nontransgenic littermates and by comparative analysis with a dataset of CNS cell type-specific genes expressed in nontransgenic mice. Most differentially-regulated genes had known or putative roles in neurons and included presynaptic and excitatory genes. Specifically, we observed changes in presynaptic factors, glutamatergic signaling, and protein scaffolding. Moreover, in the aged mice, expression levels of several genes whose expression was annotated to occur in other brain cell types were altered. Immunoblotting and immunostaining of brain samples from the TAU58/2 mice confirmed altered expression and localization of identified and network-linked proteins. Our results have revealed genes dysregulated by progressive tau accumulation in an FTD mouse model.

A case of Capnocytophaga canimorsus meningitis and bacteraemia

Capnocytophaga canimorsus is a commonly detectable commensal in the oral flora of dogs and cats, found in 25.5% and 15%, respectively, by culture and 70% and 55%, respectively, by molecular methods [1]. Formerly known as dysgonic fermenter 2 (DF-2), it was first reported in 1976 as a Gram-negative bacillus causing septicaemia and meningitis following dog bites [2]. It causes a spectrum of clinical syndromes from wound infections to bacteraemia and meningitis, especially in those with hyposplenism and alcoholism. We report a case of C. canimorsus meningitis and bacteraemia, and give a review of the relevant literature.