Hospital to offer test that cuts wait for identifying secondary infection in COVID-19 patients

Results from a study on a DNA test showed it could provide accurate pathogen detection and antibiotic resistance prediction within eight hours.

COVID-19 patients with secondary infections could get the right antibiotics more quickly, following the roll out of a rapid 24-hour test at Guy’s and St Thomas’ NHS Foundation Trust during winter 2021.

The new clinical service was implemented after researchers at the trust evaluated the rapid test between 11 April and 15 June 2020 using respiratory samples from 34 COVID-19 patients with secondary infections across seven of the trust’s intensive care units (ICUs).

According to the research paper, published in Genome Medicine on 17 November 2021, the test uses DNA sequencing to identify all bacterial and fungal pathogens in samples from patients’ lungs, as well as any antimicrobial resistance (AMR) genes present.

Results from the study demonstrated that the test “provided bacterial and fungal identification and accurate AMR prediction within an 8-[hour] laboratory workflow”, the paper said, adding that the test was 92% sensitive and 82% specific “for bacterial identification based on culture-positive and culture-negative samples, respectively”.

While previous testing required lung samples to be sent to multiple laboratories — where different bacterial and fungal cultures are set up alongside other molecular tests, taking between two and four days to return results — the trust said in a statement that the rapid test “provides enough genetic sequence to compare pathogen genomes with a database that accurately identifies patients carrying the same strain” within 24 hours. This means outbreaks can be detected at the earliest point.

Following the research, the test “can now be moved into clinical service [in winter 2021] for COVID-19 and influenza patients on ICU” at the trust.

The authors said that the provision of this technology in a service setting could “fundamentally” change the approach to managing ICU infections and provide benefit for the whole multidisciplinary team, including pharmacists, and particularly those working in an ICU setting.

Jonathan Edgeworth, director of the centre for clinical infection and diagnostics research and lead author of the study, told The Pharmaceutical Journal in a statement that although the study focused on deep respiratory samples, “it can be equally applied to other samples such as tissue fluids and biopsies including those removed at operation”.

“It therefore has potential to impact on diagnostics for many clinical services, particularly if the progress is maintained at the current pace.”

Edgeworth added that the test would “revolutionise” approaches to prevention and treatment of serious infection on ICU.

Paul Wade, consultant pharmacist in infectious diseases and chair of the antimicrobial stewardship committee at Guy’s and St Thomas’ NHS Foundation Trust, said the research “may have significant implications for antimicrobial stewardship and earlier optimisation of antibiotic choice in critically ill patients”.

He said confirmation was needed for its use within “a working COVID-19 environment” to see how it could alter and improve clinicians’ antimicrobial prescribing practices, but Wade added: “The potential benefits are exciting and could lead to improved clinical outcomes.”

The researchers said in the paper that further work was now required to scale up resources to cope with the number of tests potentially required from a routine service, compared with the small number of patients involved in the study.

Read more: How to evaluate the clinical appropriateness of an antimicrobial

Last updated
The Pharmaceutical Journal, PJ, December 2021, Vol 307, No 7956;307(7956)::DOI:10.1211/PJ.2021.1.118207

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