Decoding the “Microbial Crime Scene” – Molecular Detective Tools-Slides

Slides

Pdf Summary

This document by Dr. Natalia E. Castillo Almeida reviews syndromic diagnostic testing and next-generation sequencing (NGS) in infectious disease diagnosis, emphasizing their indications, interpretation challenges, pros and cons, and clinical utility.<br /><br />Syndromic panel-based molecular assays rapidly detect multiple pathogens and antimicrobial resistance genes directly from clinical specimens, enabling faster diagnoses than traditional methods. Common panels include blood culture identification (BCID), respiratory pathogen, pneumonia, meningitis/encephalitis, and gastrointestinal pathogen panels. Advantages are high sensitivity/specificity, automation, and reduced turnaround time, aiding timely antimicrobial stewardship and infection control. However, limitations include difficulty interpreting polymicrobial infections, inability to provide full susceptibility profiles, potential false positives, inability to detect off-target pathogens, and high costs. Accurate interpretation requires clinical context since panels may detect colonizers, low-level or non-viable organisms, or lack differentiation between infection and colonization.<br /><br />Several clinical cases illustrate use of syndromic panels: a kidney transplant patient with Serratia marcescens bacteremia treated based on BCID results; a liver transplant patient with respiratory syncytial virus (RSV) and cryptococcal infection diagnosed via respiratory and meningitis panels; and a liver transplant patient with adenovirus enteritis identified by GI pathogen panel, treated successfully with cidofovir.<br /><br />NGS, especially metagenomic cell-free DNA sequencing like the Karius test, offers detection of rare or hard-to-culture pathogens from plasma without culture. It is useful in culture-negative deep infections or when invasive procedures are contraindicated. Limitations include inability to detect RNA viruses, lack of susceptibility data, difficulty distinguishing colonizers, and high cost. Appropriate clinical scenarios and restrictions for NGS use are outlined.<br /><br />In conclusion, syndromic panels and NGS have revolutionized infectious disease diagnostics with rapid, broad pathogen detection, improving patient management and stewardship. Judicious, clinically informed use is critical to maximize benefits and minimize diagnostic pitfalls.

Keywords

syndromic diagnostic testing

next-generation sequencing

infectious disease diagnosis

syndromic panel-based molecular assays

blood culture identification (BCID)

respiratory pathogen panels

antimicrobial resistance genes

metagenomic cell-free DNA sequencing

clinical interpretation challenges

clinical utility of NGS