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19th April 2021  Product update: rapidmicrobiology staff writer

Study Shows Respiratory Panel Aids Antibiotic Stewardship in COVID & non-COVID Pneumonia Cases

OpGen, Inc. has announced the results from the highly attended webinar titled “Pneumonia Diagnosis: Bacterial Superinfection in COVID-19 Patients”, where two infectious disease experts presented their independent study results from the Unyvero Hospitalized Pneumonia (HPN) and Unyvero Lower Respiratory (LRT BAL) panels, respectively.

Their studies demonstrated that syndromic testing of lower respiratory specimens with Unyvero HPN and LRT BAL panels can improve patient care and time to appropriate targeted antibiotic therapy in COVID-19 pneumonia patients, as well as in a non-COVID-19 population with suspicion of pneumonia, including Pneumocystis jirovecii Pneumonia (PJP).

Professor and Senior Consultant Physician Christian Giske (MD, PhD), at the Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden, discussed “Diagnosing bacterial pneumonia in COVID-19” in his presentation, and highlighted several important findings from his study and key advantages of the Unyvero HPN panel compared with conventional bacterial culture:

  • Unyvero demonstrated a higher diagnostic yield (25.3% more detections) than bacterial culture, including several key pathogens of concern such as S. aureus, P. aeruginosa, S. marcescens, H. influenzae, K. oxytoca, S. maltophilia. Notably, S. maltophilia was called out as an important target on the Unyvero panel because of its intrinsic resistance against many of the standard antibiotics.
  • Analysis of chart reviews of patients that had multiple lower respiratory cultures ordered during the course of their hospital stay revealed two clinically important cohorts:

- In Group 1, culture and Unyvero HPN results were 100% concordant on the first and all subsequent samples that had been ordered. The findings in this cohort demonstrated that Unyvero HPN would enable significantly more rapid detection of pathogens not covered by empiric therapy due to intrinsic resistance, i.e., S. maltophilia, or multidrug-resistant organisms (MDROs), i.e., carbapenem-producers, within 5 hours vs. 2.5 days by culture.

- In Group 2, Unyvero HPN detected bacterial pathogens up to 7 days earlier in patient samples that were initially negative by culture, but subsequent cultures ordered during hospital stay were confirmed as positive for the same pathogen at a much later stage. As a consequence of the lack of finding any microbial etiology by culture, this group of patients was exposed to a longer duration of empirical antibiotic treatment. This group also had a longer hospital length of stay (LOS), longer ICU LOS, and longer VAP duration, which could have been shorter if antibiotics could have been tailored and targeted earlier. “The potential impact of Unyvero HPN in this group could be significantly greater than in Group 1,” stated Prof. Giske, as he presented several clinical cases of patients with an ongoing infection where culture exhibited intermittent detection of pathogen(s) impacted by antibiotics across serial sampling while Unyvero HPN demonstrated consistent and steady detection of these pathogen(s). Prof. Giske pointed out that similar findings were reported by Pickens et al. where chart reviews were performed on 4 culture-negative Acinetobacter cases that Unyvero had reported positive for Acinetobacter, and subsequent cultures grew Acinetobacter. In these cases, empiric therapy did not adequately cover for Acinetobacter and all four patients died.

Prof. Giske concluded his presentation with the following remarks:

  • Distinguishing those COVID-19 ICU patients with bacterial superinfection early and accurately is crucial for patient management and antibiotic stewardship;
  • Excellent NPV of 99.8% allows for a reduction in unnecessary antibiotics use;
  • Unyvero reduces diagnostic turnaround time to about 5 hours (vs. an average of 2.5 days for final culture results), and it can easily fit into a 24/7 lab workflow; and
  • Unyvero provides clinicians earlier data to inform antimicrobial decisions, especially in critically ill COVID-19 patients.

The second presentation focused on a number of clinical cases from the Unyvero LRT BAL study that exemplify the performance characteristics and potential clinical impact of this Unyvero panel in pneumonia diagnostic algorithms, presented by Drew Bell (PhD), Medical and Public Health Microbiology Fellow at Indiana University School of Medicine, Indianapolis, IN.

The patient population in this study (n=63) included pneumonia: Community-Acquired Pneumonia (CAP, 27), Hospital-Acquired Pneumonia (HAP, 14), Ventilator-Associated Pneumonia (VAP, 8), Aspiration Pneumonia (1), as well as non-pneumonia (13) patients.

Results of Unyvero LRT BAL were compared to conventional microbiological methods, including bacterial culture for pathogen identification and antimicrobial susceptibility testing, as well as microscopic examination for PJP.

Analysis of retrospective chart reviews performed on these patients revealed that, based on conventional microbiological results, 41% were undertreated, 19% were overtreated, while only 25% were appropriately treated, and 16% were appropriate without antibiotic treatment.

In contrast, the study demonstrated that using the Unyvero LRT BAL panel would have enabled prompt and appropriate targeted antibiotic therapy in 41.3% of cases, including escalations (i.e., detection of S. aureus and mecA 11 to 18 hours earlier than culture) and de-escalations (i.e., detection of M. catarrhalis, which would have enabled de-escalation from piperacillin/tazobactam and azithromycin to amoxicillin-clavulanate in just 5 hours), and reduced time to appropriate therapy by 25.7 hours.

This presentation also called out the fact that Pneumocystis jirovecii is a non-culturable fungus, and in the absence of PCR testing, PJP diagnosis relies on microscopic examination of trophic forms or cysts, which is laborious and insensitive.

Clinical cases were presented which demonstrated the rapid and reliable detection of Pneumocystis jirovecii using the Unyvero LRT BAL panel in just 5 hours with only about 2 minutes of hands-on time.

Key comments and concluding remarks from Dr. Bell were that “Implementing rapid molecular testing for lower respiratory specimen assessment algorithms can lead to faster identification and decrease time to appropriate escalation and de-escalation of antibiotic therapies.

The Unyvero LRT BAL panel includes fastidious organisms, as well as organisms that are difficult to culture or completely unculturable, and the minimal amount of hands-on time is a big benefit.” In addition, he noted that “the Unyvero LRT BAL panel provides a notable improvement in the diagnosis of PJP.”

For more details on the Unyvero HPN and LRT BAL panels, please use the 'Request Information' button provided below. You can access the recorded webinar on their website: OpGen.com



Date Published: 19th April 2021

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Note: This content has been edited by a rapidmicrobiology staff writer for style and content.

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