Point‐of‐care tests for lower respiratory tract infections

Multiplexed detection of respiratory pathogens with a portable analyzer in a "raw-sample-in and answer-out" manner

Coronavirus disease 2019 (COVID-19) has emerged, rapidly spread and caused significant morbidity and mortality worldwide. There is an urgent public health need for rapid, sensitive, specific, and on-site diagnostic tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In this study, a fully integrated and portable analyzer was developed to detect SARS-CoV-2 from swab samples based on solid-phase nucleic acid extraction and reverse transcription loop-mediated isothermal amplification (RT-LAMP). The swab can be directly inserted into a cassette for multiplexed detection of respiratory pathogens without pre-preparation. The overall detection process, including swab rinsing, magnetic bead-based nucleic acid extraction, and 8-plex real-time RT-LAMP, can be automatically performed in the cassette within 80 min. The functionality of the cassette was validated by detecting the presence of a SARS-CoV-2 pseudovirus and three other respiratory pathogens, i.e., Klebsiella pneumoniae, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The limit of detection (LoD) for the SARS-CoV-2 pseudovirus was 2.5 copies/μL with both primer sets (N gene and ORF1ab gene), and the three bacterial species were successfully detected with an LoD of 2.5 colony-forming units (CFU)/μL in 800 μL of swab rinse. Thus, the analyzer developed in this study has the potential to rapidly detect SARS-CoV-2 and other respiratory pathogens on site in a “raw-sample-in and answer-out” manner.

The role of hypoxia in stem cell potency and differentiation

Regenerative medicine relies on harnessing the capacity of stem cells to grow, divide and differentiate safely and predictably. This may be in the context of expanding stem cells in vitro or encouraging their expansion, mobilization and capacity to regenerate tissues either locally or remotely in vivo. In either case, understanding the stem cell niche is fundamental to recapitulating or manipulating conditions to enable therapy. It has become obvious that hypoxia plays a fundamental role in the maintenance of the stem cell niche. Low O2 benefits the self-renewal of human embryonic, hematopoietic, mesenchymal and neural stem cells, as well as improving the efficiency of genetic reprogramming to induced pluripotency. There is emerging evidence that harnessing or manipulating the hypoxic response can result in safer, more efficacious methodologies for regenerative medicine.

Microfluidic platforms for biomarker analysis

Biomarkers have been described as characteristics, most often molecular, that provide information about biological states, whether normal, pathological, or therapeutically modified. They hold great potential to assist diagnosis and prognosis, monitor disease, and assess therapeutic effectiveness. While a few biomarkers are routinely utilised clinically, these only reflect a very small percentage of all biomarkers discovered. Numerous factors contribute to the slow uptake of these new biomarkers, with challenges faced throughout the biomarker development pipeline. Microfluidics offers two important opportunities to the field of biomarkers: firstly, it can address some of these developmental obstacles, and secondly, it can provide the precise and complex platform required to bridge the gap between biomarker research and the biomarker-based analytical device market. Indeed, adoption of microfluidics has provided a new avenue for advancement, promoting clinical utilisation of both biomarkers and their analytical platforms. This review will discuss biomarkers and outline microfluidic platforms developed for biomarker analysis.

Low utilisation of diagnostic microbiology for community acquired pneumonia in regional Victoria

Aims

Diagnostic microbiology for community acquired pneumonia (CAP) provides useful information for patient management, infection control and epidemiological surveillance. Newer techniques enhance that information and the time interval for obtaining results. An audit of diagnostic microbiology utilisation, microbiological aetiology, and influence of results on prescribing practices in CAP in a regional Australian hospital setting was performed.

Methods

Clinical, microbiological and outcome data were collected by medical record review of patients discharged from Ballarat Hospital with a diagnosis of CAP over a 12 month period.

Results

Of 184 identified CAP episodes, 47 (25.5%) had no diagnostic microbiology performed. Respiratory virus polymerase chain reaction (PCR) was rarely performed (2.7% of all episodes). Acute serology was frequently requested, however paired acute and convalescent serology was infrequently performed (5/75 testing episodes; 6.7%). CAP severity was not correlated with microbiological investigation intensity. The most common pathogens identified were Streptococcus pneumoniae and Mycoplasma pneumoniae (5.4% and 2.2%, respectively). Diagnostic testing appeared to rarely influence antimicrobial prescribing.

Conclusions

In this setting, diagnostic microbiological tests such as respiratory virus PCR and urinary antigen tests are under-utilised. In contrast, sputum and serological investigations are commonly requested, however rarely influence practice. Interventions to facilitate efficient usage of diagnostic microbiology are required.

Use of flow cytometry for rapid, quantitative detection of poliovirus-infected cells via TAT peptide-delivered molecular beacons

Rapid and efficient detection of viral infection is crucial for the prevention of disease spread during an outbreak and for timely clinical management. In this paper, the utility of Tat peptide-modified molecular beacons (MBs) as a rapid diagnostic tool for the detection of virus-infected cells was demonstrated. The rapid intracellular delivery mediated by the Tat peptide enabled the detection of infected cells within 30 s, reaching saturation in signal in 30 min. This rapid detection scheme was coupled with flow cytometry (FC), resulting in an automated, high-throughput method for the identification of virus-infected cells. Because of the 2-order-of-magnitude difference in fluorescence intensity between infected and uninfected cells, as few as 1% infected cells could be detected. Because of its speed and sensitivity, this approach may be adapted for the practical diagnosis of multiple viral infections.

Point of care testing: diagnosis outside the virology laboratory

Numerous point-of-care tests (POCTs) are available to diagnose viral infections in both hospital and community settings. The ideal POCT is rapid, sensitive, specific, and simple to perform. This chapter will describe the benefits of POCTs, factors that can influence the accuracy of POCTs and highlight some limitations of POCT strategies. The sensitivity, specificity, and turn-around time of available POCTs are included for common conditions including respiratory viral infections (e.g. influenza, RSV) and blood-borne viral infections (e.g. HIV).

Effect of rapid influenza testing on the clinical management of paediatric influenza

Background  Rapid tests are now widely available to assist the diagnosis of influenza; implementation may optimise the use of antiviral and antibiotic agents in the clinical management of influenza.

Objective  To explore the clinical management of children with influenza‐like illness (ILI) when rapid influenza tests were and were not performed.

Methods  Between 15 January 2007 and 30 April 2007, a standardised questionnaire was used to record the clinical features of children aged 1–12 years who presented to office‐based paediatricians in Germany with febrile ILI during periods of local influenza activity. For each paediatric contact, a clinical diagnosis of either ‘influenza positive’, ‘influenza negative’ or ‘suspected ILI’ was made. Where performed, the outcome of a Clearview Exact Influenza A + B rapid test was recorded. Prescriptions for antiviral agents and antibiotic medications were also recorded.

Results  A total of 16 907 questionnaires were evaluated. After fever (an entry criteria for all children), cough (84·6%), fatigue/decreased activity (83·0%), rhinorrhoea (73·7%) and headache (67·1%) were the most common symptoms. Influenza was clinically diagnosed in 56·8% (9596/16 907) of cases. The antiviral oseltamivir was prescribed for 24·6% (178/725) of children who were influenza positive by symptom assessment alone and 60·1% (4618/7685) of children who were influenza positive by rapid test. Antibiotics were less commonly prescribed for children who were influenza positive by rapid test [3·5% (271/7685) versus 17·2% (125/725) for symptom assessment alone].

Conclusions  In children with ILI, a positive rapid test result for influenza promotes the rational use of antiviral agents and reduces the inappropriate use of antibiotic medications.

Lessons from a respiratory illness outbreak in an aged-care facility

This report outlines practical lessons learnt from an influenza-like outbreak in an aged-care facility in NSW, which affected 26 residents, resulted in 14 hospital admissions and was associated with six deaths. No common causative agent was identified. Key recommendations include: encouraging aged-care facilities to establish mechanisms that improve the early identification of outbreaks and timely implementation of outbreak control strategies; identifying strategies to inform general practitioners of outbreaks if they have patients residing in aged-care facilities; and improving the vaccination coverage of the aged-care workforce.