Integration of susceptibility testing and local surveillance to inform antibiotic use

EP: 1.Pathogen prevalence, emerging threats, and regional resistance patterns

EP: 2.The role of rapid diagnostics and collaboration in antibiotic stewardship

EP: 3.Guiding empirical therapy through patient risk assessment

EP: 4.Aligning treatment with risk factors, patient profiles, and MBL status

EP: 5.Approaches to challenging cases with limited therapies

EP: 6.Strategies for addressing MBL infections with targeted antibiotic combination therapy, and clinical insights from the REVISIT study

EP: 7.Evidence and trials informing treatment of resistant Gram-negative infections

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EP: 8.Integration of susceptibility testing and local surveillance to inform antibiotic use

EP: 9.Challenges and opportunities in implementing new antibiotics with QIDP and Fast Track status

EP: 10.Guiding appropriate use of colistin and polymyxins

EP: 11.Optimizing formulary decisions and new drug approval through data and team collaboration

EP: 12.Approaches to equitable and responsible antibiotic management

The introduction of new antibiotics often brings challenges in susceptibility testing, particularly when microbiology laboratories are not yet equipped or validated to test for them. Although stewardship teams may be eager to deploy a promising agent, the delay in availability of standardized testing—due to regulatory hurdles, lack of US Food and Drug Administration–cleared devices, or internal lab validation—can stall its clinical use. Many labs still rely on manual methods such as broth microdilution or gradient diffusion, which, although accurate, are time-consuming and sometimes subjective. Effective interpretation also requires a deep understanding of resistance mechanisms, species-specific resistance profiles, and the clinical context, further complicating timely decision-making.

Close collaboration between clinical teams and microbiology labs is essential to streamline these processes. Some institutions have successfully integrated microbiologists into clinical discussions, ensuring rapid communication when resistant organisms are identified. This partnership allows for reflex testing protocols, where additional susceptibility testing is automatically triggered based on specific resistance patterns, such as intermediate carbapenem resistance in Pseudomonas aeruginosa or carbapenem-resistant Acinetobacter baumannii. These preemptive systems can significantly reduce turnaround times and avoid delays in optimizing therapy for critically ill patients. However, limitations persist, such as insufficient space on testing panels, outdated breakpoint usage, and varying access to newer antimicrobial agents across institutions.

Surveillance data—both national and local—play a vital role in guiding empiric therapy decisions, especially when susceptibility results are pending. Institutions with robust resistance tracking can sometimes justify early use of newer agents when a known resistance mechanism is present and local susceptibility trends are favorable. Still, confirmatory testing remains important for data collection and clinical assurance. Continued investment in diagnostic infrastructure, lab-clinician communication, and susceptibility education is necessary to fully realize the potential of new antimicrobials in combating multidrug-resistant infections.