Conference Coverage

New tool may provide point-of-care differentiation between bacterial, viral infections


 

FROM ESPID 2020

The World Health Organization estimates that 14.9 million of 57 million annual deaths worldwide (25%) are related directly to diseases caused by bacterial and/or viral infections.

Ivana Pennisi

Ivana Pennisi

The first crucial step in order to build a successful surveillance system is to accurately identify and diagnose disease, Ivana Pennisi reminded the audience at the annual meeting of the European Society for Paediatric Infectious Diseases, held virtually this year. A problem, particularly in primary care, is differentiating between patients with bacterial infections who might benefit from antibiotics and those with viral infections where supportive treatment is generally required. One solution might a rapid point-of-care tool.

Ms. Pennisi described early experiences of using microchip technology to detect RNA biomarkers in the blood rather than look for the pathogen itself. Early results suggest high diagnostic accuracy at low cost.

It is known that when a bacteria or virus enters the body, it stimulates the immune system in a unique way leading to the expression of different genes in the host blood. As part of the Personalized Management of Febrile Illnesses study, researchers have demonstrated a number of high correlated transcripts. Of current interest are two genes which are upregulated in childhood febrile illnesses.

Ms. Pennisi, a PhD student working as part of a multidisciplinary at the department of infectious disease and Centre for Bioinspired Technology at Imperial College, London, developed loop-mediated isothermal amplification (LAMP) assays to detect for the first time host RNA signatures on a nucleic acid–based point-of-care handheld system to discriminate bacterial from viral infection. The amplification reaction is then combined with microchip technology in the well of a portable point-of-care device named Lacewing. It translates the nucleic acid amplification signal into a quantitative electrochemical signal without the need for a thermal cycler.

The combination of genomic expertise in the section of paediatrics lead by Michael Levin, PhD, and microchip-based technologies in the department of electrical and electronic engineering under the guidance of Pantelis Georgiou, PhD, enabled the team overcome many clinical challenges.

Ms. Pennisi presented her team’s early experiences with clinical samples from 455 febrile children. First, transcription isothermal amplification techniques were employed to confirm bacterial and viral infections. Results were then validated using standard fluorescent-based quantitative polymerase chain reaction (PCR) instruments. In order to define a decision boundary between bacterial and viral patients, cutoff levels were determined using multivariate logistic regression analysis. Results then were evaluated using microarrays, reverse transcriptase PCR (RT-PCR), and the eLAMP to confirm comparability with preferred techniques.

In conclusion, Ms. Pennisi reported that the two-gene signature combined with the use of eLAMP technology in a point-of-care tool offered the potential of low cost and accurate discrimination between bacterial and viral infection in febrile children. She outlined her vision for the future: “The patient sample and reagent are loaded into a disposable cartridge. This is then placed into a device to monitor in real time the reaction and share all the data via a Bluetooth to a dedicated app on a smart phone. All data and location of the outbreak are then stored in [the] cloud, making it easier for epidemiological studies and tracking of new outbreaks. We hope that by enhancing the capability of our platform, we contribute to better patient care.”

“Distinguishing between bacterial and viral infections remains one of the key questions in the daily pediatric acute care,” commented Lauri Ivaska, MD, from the department of pediatrics and adolescent medicine at Turku (Finland) University Hospital. “One of the most promising laboratory methods to do this is by measuring quantities of two specific host RNA transcripts from a blood sample. It would be of great importance if this could be done reliably by using a fast and cheap method as presented here by Ivana Pennisi.”

Ms. Pennisi had no relevant financial disclosures.

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