An international inter-laboratory study to compare digital PCR with ISO standardized qPCR assays for the detection of norovirus GI and GII in oyster tissue

An optimized digital RT-PCR (RT-dPCR) assay for the detection of human norovirus GI and GII RNA was compared with ISO 15216-conform quantitative real-time RT-PCR (RT-qPCR) assays in an interlaboratory study (ILS) among eight laboratories. A duplex GI/GII RT-dPCR assay, based on the ISO 15216-oligonucleotides, was used on a Bio-Rad QX200 platform by six laboratories. Adapted assays for Qiagen Qiacuity or ThermoFisher QuantStudio 3D were used by one laboratory each. The ILS comprised quantification of norovirus RNA in the absence of matrix and in oyster tissue samples. On average, results of the RT-dPCR assays were very similar to those obtained by RT-qPCR assays. The coefficient of variation (CV%) of norovirus GI results was, however, much lower for RT-dPCR than for RT-qPCR in intra-laboratory replicates (eight runs) and between the eight laboratories. The CV% of norovirus GII results was in the same range for both detection formats. Had in-house prepared dsDNA standards been used, the CV% of norovirus GII could have been in favor of the RT-dPCR assay. The ratio between RT-dPCR and RT-qPCR results varied per laboratory, despite using the distributed RT-qPCR dsDNA standards. The study indicates that the RT-dPCR assay is likely to increase uniformity of quantitative results between laboratories.

6 OLDER ADULTS’ DECISION-MAKING CAPACITY FOR INDEPENDENT LIVING: OCCUPATIONAL THERAPY CONTRIBUTIONS TO COLLABORATIVE MULTIDISCIPLINARY ASSESSMENT

Background

Increasing age and life expectancy, alongside the growing prevalence of dementia-related diseases, indicate more older adults are likely to experience challenges regarding their decision-making capacity (DMC). The Assisted Decision Making (Capacity) Act 2015 provides a statuary framework for adults who are experiencing difficulties with decision-making and has implications for all healthcare professionals. Occupational therapists frequently contribute to multidisciplinary assessments of older adults’ DMC for independent living (IL).

Methods

Focus groups were conducted among occupational therapists working with older adults in Ireland to explore assessment practices of DMC for IL.

Results

Fifty-two occupational therapists, from a range of hospital and community settings, participated in nine focus groups. Therapists reported using enablement strategies and occupation-based approaches when assessing DMC to address the person’s values and preferences, cognitive-functional abilities and environmental needs for IL. However, resource issues and lack of shared understanding of DMC among the multidisciplinary team constrain DMC assessment practices. Furthermore, older people are often excluded from care-planning, and IL options are determined by availability of services rather than will and preference. Multidisciplinary education on DMC is essential in shaping a cohesive approach to assessment and to enhance older adults’ participation in decision-making.

Conclusion

Multidisciplinary collaboration and commitment to person-centred approaches may lead to enhanced outcomes for maximising and supporting older adult’s DMC regarding IL. A potential leadership role for occupational therapy in assessing DMC for IL is also highlighted.

POS0156-HPR ‘THE RIGHT ADVICE, IN THE RIGHT WAY AND AT THE RIGHT TIME’: AN INNOVATIVE MULTIDISCIPLINARY APPROACH TO ADDRESS CLIENT-IDENTIFIED PARTICIPATION NEEDS IN EARLY INFLAMMATORY ARTHRITIS

Background:

Inflammatory arthritis (IA) is a complex life-long disease with negative consequences on occupational performance and significant impact on meaningful life roles. International guidelines for the clinical management of IA consistently recommend early intervention and a multidisciplinary (MDT) approach as the optimum method to address the medical, symptom and broader life impacts, however, barriers to timely access to the MDT is a common issue in clinical practice. Limited research has explored how clinical services support broader life impacts and participation restrictions associated with early disease as part of routine healthcare. Four rheumatology services in Ireland have recently reconfigured to provide an MDT-led early arthritis service which operates in parallel to traditional medical clinics. Staffed by nurses, occupational therapists, and physiotherapists this service provides assessment and management to clients with a new diagnosis of IA along a model of care within four to six weeks of diagnosis with mechanisms to follow the client over their first year of diagnosis.

Objectives:

To explore how a novel MDT-led early arthritis service addresses client-identified participation restrictions associated with early IA.

Methods:

A qualitative description (QD) study was used to explore the perspectives of service providers and service users of this MDT-led early arthritis service. Data were gathered using one-off focus groups with service providers, and individual interviews with service users.

Results:

All staff (n=15) currently working in these services participated in the focus groups. Forty-three service users with IA participated in individual interviews (males n=12: females n=31); diagnosis duration ranged from 5 to 24 months. QD principles and thematic analysis were used in data analysis.

Extensive limitations in everyday activity and restriction in participation in meaningful, age-appropriate life roles in early IA were outlined by service users and service providers. Participants described how the MDT-led model provided automatic and immediate access to services focussed on identification and management of occupation-based participation restrictions early in the disease. Participants described how the model used a flexible approach that ensured; ease of early access to a full MDT, prolonged support from the MDT, and a person-centred approach incorporating social prescribing and self-management principles. Service users emphasised the strength of the MDT approach of providing ‘the right advice, in the right way and at the right time’ as the most influential feature that assisted them to address participation restrictions and support positive health outcomes. This was accomplished by the service providers acting in a coordinated and interdisciplinary manner with a clear remit to address participation restrictions alongside the traditional symptom management approach. Findings highlight the feasibility of the MDT-led early arthritis model as an approach to address participation-based restrictions as part of routine healthcare that delivers on the rheumatology guidelines and was positively regarded by both service users and service providers.

Conclusion:

Findings provide important insights into the role of an innovative early MDT intervention approach in addressing client-identified participation needs in early IA. This model maps onto the Irish rheumatology model of care (HSE, 2018), ‘right place, right time’ approach but importantly includes a ‘right way’ approach which is identified as influential in the effective delivery of client-focussed and client-centred care.

References:

[1]HSE. (2018). Model of care for rheumatology in Ireland. Retrieved 15/09/2019, https://www.hse.ie/eng/about/who/cspd/ncps/rheumatology/achievements/model-of-care-for-rheumatology-in-ireland.pdf

Acknowledgements:

The authors, thank you to the research sites who facilitated this study & the service providers and service users who partook in the research. Thank you to Kildare Branch of Arthritis Ireland who provided funding support for the research

Disclosure of Interests:

None declared

Whole Genome Sequencing of Hepatitis A Virus Using a PCR-Free Single-Molecule Nanopore Sequencing Approach

Hepatitis A virus (HAV) is one of the most common causes of acute viral hepatitis in humans. Although HAV has a relatively small genome, there are several factors limiting whole genome sequencing such as PCR amplification artefacts and ambiguities in de novo assembly. The recently developed Oxford Nanopore technologies (ONT) allows single-molecule sequencing of long-size fragments of DNA or RNA using PCR-free strategies. We have sequenced the whole genome of HAV using a PCR-free approach by direct reverse-transcribed sequencing. We were able to sequence HAV cDNA and obtain reads over 7 kilobases in length containing almost the whole genome of the virus. The comparison of these raw long nanopore reads with the HAV reference wild type revealed a nucleotide sequence identity between 81.1 and 96.6%. By de novo assembly of all HAV reads we obtained a consensus sequence of 7362 bases, with a nucleotide sequence identity of 99.0% with the genome of the HAV strain pHM175/18f. When the assembly was performed using as reference the HAV strain pHM175/18f a consensus with a sequence similarity of 99.8 % was obtained. We have also used an ONT amplicon-based assay to sequence two fragments of the VP3 and VP1 regions which showed a sequence similarity of 100% with matching regions of the consensus sequence obtained using the direct cDNA sequencing approach. This study showed the applicability of ONT sequencing technologies to obtain the whole genome of HAV by direct cDNA nanopore sequencing, highlighting the utility of this PCR-free approach for HAV characterization and potentially other viruses of the Picornaviridae family.

Use of F-Specific RNA Bacteriophage to Estimate Infectious Norovirus Levels in Oysters

Contamination of bivalve shellfish, particularly oysters, with norovirus is recognised as a significant food safety risk. Methods for quantification of norovirus in oysters using the quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) are well established, and various studies using RT-qPCR have detected norovirus in a considerable proportion of oyster samples, both in the UK and elsewhere. However, RT-qPCR detects viral genome, and by its nature is unable to discriminate between positive results caused by infectious viruses and those caused by non-infectious remnants including damaged virus particles and naked RNA. As a result, a number of alternative or complementary approaches to RT-qPCR testing have been proposed, including the use of infectious viral indicator organisms, most frequently F-specific RNA bacteriophage (F-RNA phage). In this study, we investigated the relationships between F-RNA phage and norovirus in digestive tissues from two sets of oyster samples, one randomly collected at retail (630 samples), and one linked to suspected norovirus illness outbreaks (nine samples). A positive association and correlation between PCR-detectable levels of genogroup II F-RNA bacteriophage (associated with human faecal contamination) and norovirus was found in both sets of samples, with more samples positive for genogroup II phage, at generally higher levels than norovirus. Levels of both viruses were higher in outbreak-related than retail samples. Infectious F-RNA phage was detected in 47.8% of all retail samples, and for a subset of 224 samples where characterisation of phage was carried out, infectious GII phage was detected in 30.4%. Infectious GII phage was detected in all outbreak-related samples. Determination of infectivity ratios by comparing levels of PCR-detectable (copies/g) and infectious GII phage (pfu/g) revealed that in the majority of cases less than 10% of virus detected by RT-qPCR was infectious. Application of these ratios to estimate infectious norovirus levels indicated that while 77.8% of outbreak-related samples contained > 5 estimated infectious norovirus/g, only 13.7% of retail samples did. Use of a combination of levels of PCR-detectable norovirus and infectious F-RNA phage showed that while only 7.0% of retail samples contained both > 100 copies/g norovirus and > 10 pfu/g F-RNA phage, these combined levels were present in 77.8% of outbreak-related samples, and 75.9% of retail samples with > 5 estimated infectious norovirus/g. We therefore suggest that combining RT-qPCR testing with a test for infectious F-RNA phage has the potential to better estimate health risks, and to better predict the presence of infectious norovirus than RT-qPCR testing alone.

The effect of glycosaminoglycan depletion on the friction and deformation of articular cartilage

Glycosaminoglycans (GAGs) have been shown to be responsible for the interstitial fluid pressurization of articular cartilage and hence its compressive stiffness and load-bearing properties. Contradictory evidence has been presented in the literature on the effect of depleting GAGs on the friction properties of articular cartilage. The aim of this study was to investigate the effect of depleting GAGs on the friction and deformation characteristics of articular cartilage under different tribological conditions.

A pin-on-plate machine was utilized to measure the coefficient of friction of native and chondroitinase ABC (CaseABC)-treated articular cartilage under two different models: static (4 mm/s start-up velocity) and dynamic (4 mm/s sliding velocity; 4 mm stroke length) under a load of 25 N (0.4 MPa contact stress) and with phosphate-buffered saline as the lubricant. Indentation tests were carried out at 1 N and 2 N loads (0.14 MPa and 0.28 MPa contact stress levels) to study the deformation characteristics of both native and GAG-depleted cartilage samples.

CaseABC treatment rendered the cartilage tissue soft owing to the loss of compressive stiff-ness and a sulphated-sugar assay confirmed the loss of GAGs from the cartilage samples. CaseABC treatment significantly increased (by more than 50 per cent) the friction levels in the dynamic model ( p < 0.05) at higher loading times owing to the loss of biphasic lubrication. CaseABC treatment had no effect on friction in the static model in which the cartilage surfaces did not have an opportunity to recover fluid because of static loading unlike the cartilage tissue in the dynamic model, in which translation of the cartilage surfaces was involved, ensuring effective biphasic lubrication. Therefore the depletion of GAGs had a smaller effect on the coefficient of friction for the static model. Indentation tests showed that GAG-depleted cartilage samples had a lower elastic modulus and higher permeability than native tissue. These results corroborate the role of GAGs in the compressive and friction properties of articular cartilage and emphasize the need for developing strategies to control GAG loss from diseased articular cartilage tissue.

A pilot study of attention deficits, balance control and falls in the subacute stage following stroke

OBJECTIVES

To (1) identify and monitor changes in deficits of attention and balance in the subacute stage following stroke, (2) investigate fall events, (3) explore relationships between deficits of attention, balance and falling post stroke.

DESIGN

A prospective observational study.

SETTING

Hospitalized patients with stroke were recruited from a rehabilitation ward.

SUBJECTS

Fourteen subjects were recruited, 13 subjects (age 21-80 years) completed all assessments. Ten had right and three had left hemispheric lesions. Eight subjects were male.

MAIN OUTCOME MEASURES

Subjects were assessed on two occasions during a six-week period. Standardized tests were used to measure unilateral visual neglect, sustained and selective attention and balance. Fall histories were collected by chart review and semi-structured interview.

RESULTS

At the initial assessment six subjects had sustained auditory attention deficit, eight had deficits of auditory selective attention, 12 had visual selective attention deficits and seven subjects presented with visual inattention. Scores for visual inattention and visual selective attention improved over time (p = 0.006, p = 0.026 respectively) as did scores for balance control (p = 0.001). Auditory selective attention scores at the first assessment were found to correlate with measures of balance (p < 0.01), subjects with normal attention scores achieved better balance scores. Four subjects fell at least once during the six weeks. Scores for attention and balance of fallers were not found to be significantly different from the scores of nonfallers.

CONCLUSIONS

The sample size was small but high levels of attention deficit were identified. Findings suggest a weak or no relationship between attention deficits and falls. Further studies are required to explore the extent of attention deficits post stroke and its impact on balance control and falling.

The importance of paediatrics in developing countries

The rate of tuberculous infection is high. In many areas by the age of ten to fourteen years almost half the population have become tuberculin positive, not as a result of BCG vaccination, but as a result of infection acquired from someone in their environment.The fact that you have selected paediatric emergencies as one of the themes of this congress is merely a reflection that the overall mortality of children admitted to the children’s wards in a great teaching hospital such as you have here in Surabaya is of the order of fifteen to twenty per cent.