Professor Gian Maria Rossolini Discusses the Global Threat of Antimicrobial Resistance and the Future of Clinical Microbiology

Antimicrobial resistance (AMR) continues to rank among the world's most urgent public health threats, challenging clinicians, microbiology laboratories, and infection prevention teams across every health care setting. As resistant pathogens evolve and spread, advances in surveillance, diagnostics, antimicrobial stewardship, and laboratory medicine are becoming increasingly important to protecting patients and preserving the effectiveness of existing therapies.

To better understand the current state of AMR and where the field is headed, Infection Control Today spoke with Gian Maria Rossolini, MD, professor of microbiology and clinical microbiology at the University of Florence, Italy, and director of the Clinical Microbiology and Virology Unit at Florence Careggi University Hospital. Rossolini is internationally recognized for his work in antimicrobial resistance, clinical microbiology, surveillance, and the clinical impact of drug-resistant infections. He has authored more than 470 scientific publications indexed in PubMed and serves on numerous international scientific initiatives focused on combating antimicrobial resistance.

In this exclusive Q&A with Infection Control Today^® (ICT^®), Rossolini discusses the evolving AMR landscape, emerging resistance mechanisms, the role of rapid diagnostics and surveillance, and what infection preventionists and clinical microbiologists should prioritize as they prepare for future challenges.

ICT: In real-world hospital settings, what are the consequences—clinically and operationally—of delayed or missed multidrug-resistant organisms (MDRO) identification, and where do you see those gaps most often occurring today?

Gian Maria Rossolini, MD: Delayed or missed identification of MDRO carriage in hospital settings is expected to reduce the efficacy of infection prevention and control (IPC) practices and, consequently, to increase the risk of MDRO dissemination within the health care context. Moreover, delayed or missed identification of MDRO carriage could also [affect] the selection of the initial empiric treatment for infections in terms of delayed or lack of MDRO coverage, which might reflect on clinical outcomes, especially with some categories of high-risk patients. Similar gaps are expected to occur most often in settings where diagnostic microbiology is outsourced, with consequent delays in the pre-analytical phase.

ICT: Rapid molecular tests can provide faster results, but not all results are equally actionable. How should infection preventionists and clinicians interpret and prioritize MDRO screening data without creating confusion or unnecessary interventions?

GMR: Rapid molecular tests are faster and more sensitive than conventional culture for screening of MDRO carriage. Provided that rapid molecular tests have been validated for in vitro diagnostic use and are performed following the recommended protocols, including suitable controls, the results of these tests are reliable and actionable for infection preventionists to enforce more rapidly the IPC measures aimed at contrasting MDRO dissemination within the health care setting.

Moreover, when dealing with high-risk patients with infections, clinicians can rely on the faster, more sensitive results from rapid molecular tests to screen for MDRO carriage, enabling faster decisions on empiric antimicrobial regimens while awaiting information about the infecting pathogens.

ICT: Isolation and cohorting decisions often need to be made quickly, sometimes with incomplete information. How does rapid MDRO screening shift that risk calculus, and are there situations where faster results could complicate decision-making?

GMR: In principle, preemptive isolation should be adopted for all new admissions considered at risk of MDRO carriage while awaiting screening results, and isolation/cohorting decisions should then be consolidated based on those results. The rapidity of MDRO screening will reduce costs associated with unnecessary preemptive isolation and optimize bed occupancy. Therefore, faster results of MDRO screening are expected to be beneficial in terms of saving resources and could also improve the overall adherence with preemptive isolation without complicating the decision-making process.

ICT: We often talk about the promise of rapid testing, but implementation is rarely straightforward. What have you seen as the biggest points of friction—whether cultural, logistical, or financial—when hospitals try to integrate rapid MDRO screening into existing workflows?

GMR: In our experience, the biggest points of friction in the introduction of rapid screening for MDRO carriage in the diagnostic routine have been of a financial and logistical nature. Financial issues were related to the higher cost of rapid testing systems vs. conventional culture, which was proportionate to the magnitude of differential testing costs. Logistical issues were related to the need to rethink and change the laboratory workflow for MDRO screening to fully exploit the advantage of rapid vs. conventional MDRO screening in terms of reduced time-to-response, with the overall objective of reporting results on the same day.

ICT: How does rapid MDRO screening influence patient flow, particularly in high-pressure environments like the ED or ICU, where bed availability and throughput are constant challenges?

GMR: Due to the faster responses, rapid MDRO screening is expected to have a greater influence on patient flow in higher-pressure settings, such as the Intensive Care Units. In the Emergency Department, on the other hand, rapid screening for MDRO carriage plays a more limited role, since this information is intended mainly for hospitalized patients and MDRO screening is usually performed upon definitive hospital admission.

ICT: What are the risks of over-reliance on rapid screening technologies—whether in terms of false positives, colonization vs infection, or a false sense of security—and how should teams mitigate those risks?

GMR: Screening for MDRO carriage has the purpose of identifying patients who should be subjected to contact isolation/cohorting, and to contrast the dissemination of MDRO within health care settings. Rapid MDRO screening technologies based on molecular testing are known to be more sensitive than conventional culture-based screening. Provided that the tests have been validated for in vitro diagnostic use and are performed following recommended protocols with suitable controls (including controls for the quality of sampling), results are expected to be accurate and not to entail major risks of false positives. However, it should be considered that rapid MDRO screening based on molecular testing can only detect MDRO covered by the diagnostic platform, while those that are not targeted by the diagnostic platform will be missed. Therefore, their sensitivity could vary according to the local epidemiological context, which should always be considered when introducing these systems in the diagnostic practice.

Notably, systems for rapid screening of MDRO carriage are not meant to discriminate between carriage and infection, although carriers may be at varying risk of infection depending on the MDRO type and the patient’s conditions.

ICT: As antimicrobial resistance patterns continue to shift, how should hospitals rethink their surveillance strategies to move from reactive to more proactive, intelligence-driven approaches?

GMR: The epidemiology of antimicrobial resistance can vary markedly across settings and may evolve rapidly. Therefore, to maximize their impact in a cost-effective manner, surveillance strategies for MDRO carriage should be carefully tailored to local epidemiology and periodically reassessed and updated in light of evolving AMR epidemiology and emerging technological solutions, in accordance with the principles of diagnostic stewardship.

ICT: Not all hospitals have equal access to rapid molecular diagnostics. How do we ensure that advances in MDRO screening don’t widen gaps in infection prevention capabilities across different health systems?

GMR: Rigorous IPC practices are the mainstay for combating the spread of MDROs in health care settings. Therefore, it is important that these practices, which include screening of MDRO carriage, are implemented whenever there is a risk of MDRO dissemination, including in lower- and medium-income settings where the burden of AMR is often exceedingly high. To promote IPC for MDRO at the global level, including lower-resources areas, 2 actions should be fostered: a) promoting education about the added value and importance of IPC practices for contrasting MDRO spreading, in a context-sensitive manner; b) supporting the availability of rapid MDRO screening systems at costs affordable also for weaker health care systems.

ICT: Beyond speed, what metrics should hospitals be using to evaluate the true impact of rapid MDRO screening—both in terms of patient outcomes and operational efficiency?

GMR: Beyond the overall reduction of turnaround times in the MDRO screening process, the following metrics could be used to evaluate the impact of the introduction of a rapid MDRO screening program:

a) incidence of in-hospital colonization by MDRO, over time, concerning patient outcomes; b) average time of patient release from preemptive isolation or definitive allocation to isolation/cohorting, over time, concerning operational efficiency.

ICT: Looking ahead, what role do you see rapid diagnostics playing in the broader fight against antimicrobial resistance, and what still needs to change for that potential to be fully realized?

GMR: Overall, rapid diagnostics are already playing a remarkable role in the fight against antimicrobial resistance by improving the efficacy of IPC practices through increased rapidity and sensitivity in MDRO screening. Moreover, some rapid diagnostic systems are also suitable for near-patient testing and could be advantageous in health care settings where diagnostic microbiology is normally outsourced to a central laboratory (eg, many long-term care facilities). Future developments in this area of diagnostics, including systems for rapid identification of broader arrays of MDRO at affordable costs, are expected to expand the potential of this approach to contrast AMR dissemination.