Adoption of Rapid Diagnostic Tools, Susceptibility Testing for Gram-Negative Infections

When thinking of diagnosing and treating gram-negative infections there are some inherent challenges including quick development to antimicrobial resistance, the time-consuming nature of traditional tests, and the limitations of rapid diagnostics in this area. And the unique cellular structure of gram-negative bacteria, which includes an additional outer membrane, can make antibiotic treatment more difficult.^1-4

One of the emerging areas within infectious disease is the development of diagnostic tools and how they are applicable to gram-negative infections. Some of these innovations include rapid diagnostics, next-generation sequencing (NGS), CRISPR-based methods, utilizing AI for data analysis and prediction, and the expansion of point-of-care (POC) testing, enabling faster, more accurate diagnoses.⁵

Rodney E. Rohde, PhD, SV/SM/MB(ASCP)CM, FACSc, is a University Distinguished and Regents’ professor and chair for the Clinical Laboratory Science (CLS) Program in the College of Health Professions (CHP) at Texas State University mentions a few of the rapid tests for identifying gram-negative bacteria (GNB) including the Biofire FilmArray for blood culture identification, the Cepheid GeneXpert, a platform to rapidly detect carbapenemase resistance genes, the Verigene Blood-Culture Gram-Negative (BC-GN) test is a rapid, microarray-based nucleic acid test that identifies common Gram-negative bacteria and detects specific antibiotic resistance genes directly from positive blood cultures within hours, The BD Max Enteric Bacterial Panel (EBP) is a real-time PCR diagnostic test that identifies common enteric bacterial pathogens, and the MALDI-TOF MS, which is a rapid method for identifying microorganisms and other biomolecules by analyzing their unique protein "fingerprints." He notes the last one’s growth in hospitals and testing facilities.

“The MALDI TOF in general, as many of our audience will know, is becoming more and more implemented especially in larger healthcare systems across the country, including Texas; it gives you a faster turnaround,” Rohde said.

In terms of susceptibility testing for newer antimicrobials, Rohde says there are a lot of variables involved including your location, access these tools, and the patient’s underlying comorbidities.

“There's a variety available to different microbiology laboratories in which clinicians are ordering those tests… you still might need to know as a clinician to interact with that microbiology laboratory team, the pharmacist, and others involved, to pick the right susceptibility profile test.”

With the underlying challenges of identifying Gram-negative infections, and finding the right antimicrobials, Rohde stresses the importance of an all-hands on deck approach of building a team that includes clinicians, laboratory professionals, pharmacists, and everyone who touches patient care.

He believes everyone on these care teams should be pulling together using their education and clinical experience to use “collaborative communication.”

He stresses this to not only people in the fields now but wants to see this approach taught in educational institutions, where they are training future professionals.

“That should be a part of the bread and butter of the education process now—no silos,” Rohde said. “We can’t operate like that anymore in the global world we live in.”

Check out Rohde’s podcast, From Pathogen to Infectious Disease Diagnosis.

References
1. Giacobbe D, Giani T, Bassetti M, Marchese A, Viscoli C, Rossolini G. Rapid microbiological tests for bloodstream infections due to multidrug resistant Gram-negative bacteria: therapeutic implications. Clinical Microbiology and Infection. Volume 26, Issue 6, 2020. Pages 713-722. https://doi.org/10.1016/j.cmi.2019.09.023
2. Anton-Vazquez, V., & Planche, T. (2021). Gram-negative blood stream infections: prospects and challenges of rapid antimicrobial susceptibility testing. Expert Review of Anti-Infective Therapy, 20(4), 483–485. https://doi.org/10.1080/14787210.2022.1999805
3. Why are Gram negative Bacteria Harder to Kill due to Antibiotic resistance? Crestone. Accessed September 15, 2025.
https://crestonepharma.com/why-are-gram-negative-bacteria-harder-to-kill-with-antibiotics.
4. Ducret YV. Gram-negative bacteria: Unveiling the complexity and resilience of a diverse group. J Arch Ind Biot. 2023;7(3):147
5. Ciotti B, Nicolai E, Pieri M,Development and optimization of diagnostic assays for infectious diseases. LabMed Discovery. Volume 1, Issue 2. 2024. https://doi.org/10.1016/j.lmd.2024.100032