The Critical Role of Diagnostics in Antimicrobial Stewardship

Antimicrobial resistance (AMR) is a pressing global health challenge. While much of the discussion is focused on future implications, resistant infections are already having a profound impact. In 2019, bacterial AMR was directly responsible for an estimated 1.27 million deaths worldwide - more than HIV/AIDs or malaria.¹ The actions we take today will determine the trajectory of this crisis. Without decisive intervention, AMR-related deaths are expected to increase significantly in the coming decades. The Global Research on Antimicrobial Resistance (GRAM) Project forecasts an additional 39 million deaths from 2025 to 2050 due to AMR strains.¹ The factors contributing to AMR are well known. Decades of improper and excessive antibiotic use, both in livestock and in humans, have enabled antimicrobial-resistant pathogens to evolve and thrive. In healthcare, over-prescribing remains widespread, even in developed nations with advanced healthcare systems. In the U.S., the CDC estimates that more than one in four outpatient antibiotic prescriptions are unnecessary.² Even when antimicrobials are appropriately prescribed, patient misuse contributes to resistance. Some fail to complete the entire course, while others self-medicate later with leftover antibiotics-exposing pathogens to suboptimal doses. Over time, natural selection and genetic adaptation allow surviving bacteria to develop stronger defenses, making them harder to treat. Compounding the problem, the pipeline for new antibiotics is narrowing. Efforts to discover and develop truly novel antimicrobials have declined, leaving healthcare professionals with limited options for effective infection control in the future.³ As resistance continues to outpace innovation, the urgency to preserve existing treatments and rethink antimicrobial use has never been greater.

Despite these challenges, the fight against AMR remains both urgent and achievable. Broad adoption of antimicrobial stewardship best practice,s combined with advancements in new technology, can drive meaningful change. In particular, the enhanced efficiency, precision, and versatility of today’s PCR diagnostic platforms can empower healthcare professionals to make more informed decisions about antibiotic use. Implementing stewardship practices and leveraging advanced diagnostics are critical first steps toward improved patient care, stronger antimicrobial stewardship, and the preservation of antimicrobial efficacy in the future.

Accurately Diagnosing Viral, Bacterial, and Fungal Infections

Many hospitals have a program in place to advance antimicrobial stewardship within their facilities. However, an estimated 80-90% of antibiotic use occurs in outpatient settings such as doctors’ offices and urgent care centers,² where stewardship efforts are often less structured. In these settings, clinicians face unique challenges: navigating patient expectations for immediate treatment while oftentimes working with limited diagnostic tools and time constraints. Balancing the need for rapid decision-making with responsible antibiotic use is essential to curbing AMR in the broader healthcare landscape.

The success of antimicrobial stewardship programs in outpatient settings relies on the successful integration of timely and accurate diagnostics. Clinical diagnoses based solely on symptoms and clinical acumen lack reliability in distinguishing between bacterial, viral, or fungal infections, the key determinant for whether antibiotics will be effective. Studies have shown that antibiotics are often prescribed to treat acute upper respiratory infections, even though most are caused by viruses.⁴ Additionally, an analysis of emergency department decision making found only 36% of influenza cases were correctly identified based on clinical symptoms, compared to over 98% accuracy with rapid PCR testing.⁵ This challenge extends beyond respiratory infections to other disease areas, such as sexually transmitted infections (STIs). Gonorrhea and Chlamydia, for example, share overlapping symptoms but require distinct treatments, especially with rising antibiotic resistance. A study on syndromic management of STIs in urgent care found that 68.8% of patients were over-treated with antibiotics despite not having an infection, while 8.2% were undertreated, leading to missed cases.⁶ Without definitive diagnostic information, even well-intentioned clinical judgment can result in unnecessary use of broad-spectrum antibiotics, increasing costs, exposing patients to avoidable side effects, and accelerating antibiotic resistance. Expanding access to rapid molecular diagnostics in outpatient and urgent care-type settings provides the precision needed to drive responsible prescribing practices, ensuring that patients receive the right treatment while minimizing the risks of antimicrobial overuse.

Today’s molecular diagnostics can guide triage and treatment decisions across inpatient and outpatient settings. Polymerase chain reaction (PCR) testing, the gold standard in molecular diagnostic technology, continues to evolve in response to clinical needs. Aligning a patient’s presentation with a provider’s clinical acumen, Targeted panels (detecting 2-5 pathogens) and expanded panels (detecting 6+ pathogens) offer flexible options. These multiplex panels enable the simultaneous detection of multiple infections from a single patient sample while also distinguishing between co-infecting pathogens, such as RSV and SARS-CoV-2, or gonorrhea and Chlamydia, ensuring accurate diagnosis and targeted treatment.

With user-friendly benchtop solutions, new PCR testing platforms are expanding into the point of care, no longer restricted by the clinical infrastructure and laboratory expertise that was previously required. Integrating point-of-care (POC) testing in outpatient settings can transform the diagnostic workflow, providing results within the same appointment. Turnaround time is critical for antimicrobial stewardship: one real-world analysis found that rapid molecular POC testing for SARS-CoV-2 led to lower antibiotic prescription rates as providers were able to prescribe targeted antivirals.⁷ Faster, more accurate results not only improve patient satisfaction by reducing wait times and uncertainty but also strengthen provider confidence in clinical decision-making, ensuring precise and appropriate treatment with reliable POC diagnostics.

Communicating Clinical Decisions

While innovative diagnostics can empower provider decision-making, clinical judgment remains complex and multifaceted. No single blood test or nasal swab can account for patient presentation, history, immunocompetency, or other critical factors that may influence treatment decisions. However, having the right diagnostic tools provides a strong foundation for confident, evidence-based decision making. This, in turn, supports more effective patient counseling, helping providers communicate when antibiotics are necessary - and when they are not - reinforcing antimicrobial stewardship and improving patient understanding.

Patient (or parent) education can be especially important in pediatric care. Five out of every six infants will develop acute otitis media (an ear infection) before the age of three.⁸ However, not all ear pain is caused by infection, and some ear infections will resolve without antibiotics.⁸ It is important for parents to understand why a prescription for antibiotics is not given, even when the child is uncomfortable or in pain. Once again, diagnostics can play a key role in supporting patient education. With point-of-care testing, results are available within the same appointment, allowing clinicians to provide real-time explanations and reinforce appropriate treatment decisions. This immediate feedback helps build trust, reduces unnecessary antibiotic use, and encourages collaboration with pharmacists and infection control specialists to implement stewardship best practices.

Optimizing Antimicrobial Selection Through Diagnostics: A Targeted Approach

Even with longer turnaround times, bacterial culture and sensitivity testing remain valuable tools in antimicrobial stewardship. While molecular diagnostics provide rapid identification of pathogens, culture-based methods play a critical role in assessing antibiotic susceptibility and determining the most effective treatment. For confirmed bacterial infections, such as urinary tract infections (UTIs), antibiotics can be prescribed based on clinical suspicion and then confirmed through culture and sensitivity testing. Within one to two days, patients can be informed whether their prescribed antibiotic is the most effective choice, ensuring treatment remains timely while allowing for optimization. This is especially important for at-risk individuals, including the elderly and immunocompromised, where early intervention and precise antimicrobial selection can significantly impact outcomes.

An important consideration in bacterial infection treatment is the distinction between broad-spectrum and narrow-spectrum antibiotics. Broad-spectrum antibiotics such as tetracyclines and fluoroquinolones are a “catch-all,” targeting both gram-positive and gram-negative bacteria. In contrast, narrow-spectrum antibiotics are more selective, inhibiting specific bacterial species. Due to the widespread effects on the human microbiota, broad-spectrum antibiotics are associated with stronger side effects and an increased risk for the development of antibiotic resistance. As a result, they should ideally be reserved for complex infections,⁹ where targeted therapy is not immediately feasible.

Early pathogen identification enables the use of appropriate narrow-spectrum antibiotics, limiting unnecessary broad-spectrum exposure and ensuring that these powerful agents are used only when truly necessary. Alongside these stewardship efforts, there remains an urgent need for new drug development. Novel antibiotics are essential to combat increasingly resistant strains, yet their development faces significant challenges. The World Health Organization (WHO) attributes the decline in new antibiotic approvals to lengthy development timelines (approximately 10-15 years), high costs, and low success rates.¹⁰ Beyond these barriers, a deeper concern is the lack of true innovation. Many new antibiotics are variations of existing classes rather than novel modalities with fundamentally different mechanisms of action.

This incremental approach leaves fewer obstacles for AMR infections to overcome. Without a pipeline of truly new treatments, the global healthcare community must prioritize maximizing and preserving the effectiveness of existing antimicrobials through stewardship and strategic use.

A Collaborative Path Forward

Achieving meaningful progress in antimicrobial stewardship requires a collaborative effort. Real-world studies and data-driven insights can help refine best practices, while partnerships with advocacy groups play a critical role in increasing awareness and fostering responsible antibiotic use. Industry collaborations further strengthen this space by advancing diagnostic innovations, expanding education, and supporting the development of new stewardship initiatives.

Beyond these efforts, deeper collaboration between healthcare providers, policymakers, and research institutions is essential to integrating stewardship strategies into clinical workflows. Regulatory support and policy-driven initiatives can facilitate the adoption of new diagnostic technologies, ensuring they become part of clinical decision-making.

Additionally, strengthening and supporting global surveillance networks can help track emerging resistance patterns, guiding both clinical and policy responses. Improving access to rapid diagnostics is vital for equitable healthcare, particularly in decentralized settings such as urgent care centers, physician office labs, and local pharmacy clinics. Expanding infrastructure, increasing affordability, and ensuring widespread availability of point-of-care testing can help bridge the gap in diagnostic accessibility. Integrating rapid diagnostics into routine care pathways can also enhance early detection of infections, allowing for more precise antimicrobial selection and better patient management.

Lastly, strengthening antimicrobial stewardship education for healthcare professionals at all levels - from medical students to experienced clinicians - can further support adherence to best practices. By working together across research, education, policy, innovation, and clinical practice, we can close the gaps in antimicrobial stewardship, ensuring that patients receive appropriate treatment while safeguarding antibiotic effectiveness for future generations.

Antimicrobial stewardship is complex. However, its core principle remains simple: The right drug, at the right dose, for the right duration. Achieving this requires clinicians to have accurate and timely diagnostic information. Inappropriate antibiotic use thrives in uncertainty when the exact cause of an infection is unclear, leading to unnecessary use. This uncertainty also makes it harder to communicate treatment decisions to patients. When antibiotics are not appropriate, clear diagnoses provide a foundation for a personalized discussion about why they may not be appropriate or beneficial. For bacterial infections requiring treatment, diagnostics can help identify a specific pathogen, enabling clinicians to confidently prescribe narrow-spectrum antibiotics that minimize microbiome disruption and help preserve the efficacy of current drugs. As microbes evolve to evade existing therapies, the healthcare community must evolve as well, leveraging diagnostic precision to drive smarter, more sustainable antimicrobial use.

References

1. Naghavi M, et al. Global burden of bacterial antimicrobial resistance 1990–2021: a systematic analysis with forecasts to 2050. The Lancet. 2024;404(10459):1199-1226. doi:10.1016/S0140-6736(24)00303-9. Available from: https://pubmed.ncbi.nlm.nih. Gov/39299261/ Retrieved March 6, 2025.
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10. World Health Organization. Lack of innovation set to undermine antibiotic performance and health gains [Internet]. 2022 [cited 2025 Feb 14]. Available from:https://www.who.Intt/news/item/22-06-2022-22-06-2022-lack-of-innovation-set-toundermine-antibiotic performance-and-health-gains. Retrieved March 6, 2025.

Author Details 

Jeanie Bach, MSN, RN, CCRN- Disease Area Partner for Infectious Disease, Roche Diagnostics.

Jeanie Bach, MSN, RN, CCRN, is a Disease Area Partner for Infectious Disease at Roche Diagnostics, based in Arizona. She holds a master’s degree in nursing with a focus on Clinical Leadership from the University of Arizona and certification in Critical Care. With nearly 20 years of experience in intensive care and emergency department environments, Jeanie plays a vital role in leading medical teams across infectious disease initiatives, with a focus on respiratory conditions, sepsis, and antimicrobial stewardship. As a subject matter expert on clinical decision-making relevance and impact, she ensures diagnostic tools are both meaningful and actionable for healthcare providers and patients. Jeanie collaborates with investigative teams to generate evidence supporting the clinical value of diagnostics, driving innovation to enhance precision in infectious disease management. Additionally, she co-leads initiatives exploring diagnostic technology advancements, ensuring practical application in real-world healthcare settings while improving clinical decision-making and patient outcomes.

Publication Details

This article appeared in American Pharmaceutical Review:

Vol. 28, No. 3
April 2025

Pages: 14-17

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