ESCMID 2026: Updates on Antibiotic Stewardship

17 Apr - 21 Apr, 26

ESCMID 2026

Munich, Germany

17 Apr - 21 Apr, 26

ESCMID 2026

Munich, Germany

High-Risk Clones and Resistance Gene Convergence Among Community Uropathogens in India: Genomic Evidence from a Nationwide Study

Presenter: S. Pundir.

This multicentric cross-sectional study evaluated the prevalence, antimicrobial susceptibility, and genomic resistance determinants of uropathogens in community settings across India over 1.5 years. Among 6,009 patients with suspected UTI, significant bacteriuria was detected in 11.8% (711 isolates). The most common pathogens were Escherichia coli (63%, 448/711) and Klebsiella pneumoniae (15.7%, 112/711). In E. coli, multidrug resistance (MDR) and ESBL production were observed in 64.5% and 65.4% of isolates, respectively. High-risk clones ST131 (25%) and ST1193 (10.7%) were identified, frequently carrying plasmid replicons IncFIB (63.1%) and IncFIA (52.6%), and the transposon Tn2680 (46.6%).

In K. pneumoniae, MDR and ESBL prevalence were 39.2% and 56.2%, with ST15, ST16, and ST231 each accounting for 20% of isolates. Multiple β-lactamase genes were detected, including blaNDM-5 (33.3%), blaOXA-1 (53.3%), blaCTX-M-15 (60%), and blaTEM-4 (60%). Notably, four ESBL-positive isolates co-harbored blaCTX-M-15 and blaOXA-232 on ColKP3 plasmids.

Overall, the study highlights a high burden of MDR and ESBL-producing uropathogens with widespread dissemination of high-risk clones and co-existing resistance genes in community settings.

Is the High Prevalence of Antibiotic Resistance in LMICS the Result of Local or Global Emergence?

Presenter: Sepideh Benvari

This interdisciplinary genomic study investigated the origins of antibiotic resistance (ABR) in Escherichia coli causing urinary tract infections across East Africa, using 857 isolates from Kenya, Tanzania, and Uganda. Pangenome analysis with a global reference dataset (n=2,464) showed that 42% of East African isolates carried more ABR categories than expected for their cluster, indicating local emergence of resistance. Among dominant lineages (ST131, ST10, ST69, ST1193; n=268), ancestral state reconstruction identified 1,463 ABR determinants, of which 20% had emerged locally, and 46% of isolates carried at least one locally emerged determinant.

The findings indicate that both global dissemination of resistant lineages and local emergence contribute to the high burden of resistance. Factors associated with local emergence included male sex, lack of access to a flush toilet, lower educational attainment, recruitment from primary care, and household contact with manure.

The study highlights the combined role of global and local drivers in shaping ABR patterns, with social and environmental factors contributing to locally emerged resistance.

Caste-Based Disparities and AMR Risks

Presenter: Srishti Goel

This study examined the role of caste-based inequalities in shaping antimicrobial resistance (AMR) risk in South Asia, with a focus on India. A conceptual framework was developed to illustrate how caste-based discrimination influences infection risk, antibiotic use, and access to healthcare. Descriptive analyses using National Family Health Survey (NFHS-5, 2019–2021) data assessed differences across caste groups in key AMR-related determinants, including water, sanitation, and hygiene (WASH), nutritional status, and prevalence of sexually transmitted diseases and infections (STDs/STIs).

Findings showed that lower caste households had reduced access to WASH facilities, poorer nutritional status, and higher reported incidence of STDs/STIs. These disparities were more pronounced among women from marginalized caste groups.

In conclusion, the study highlights how social, economic, and structural inequalities contribute to differential AMR risk, emphasizing the need for intersectional and interdisciplinary approaches to address these disparities.

"No Breakpoints? No Problem!" Evaluating Gentamicin Perioperative Prophylaxis for Pseudomonas Aeruginosa Asymptomatic Bacteriuria Before Urological Surgery

Presenter: Niamh Reidy

This retrospective study evaluated the effectiveness of perioperative gentamicin prophylaxis in patients with asymptomatic bacteriuria undergoing urological procedures (January 2024–September 2025), including those with Pseudomonas aeruginosa and Enterobacterales. Patients were grouped as: P. aeruginosa with gentamicin MIC <4 mg/L (n=57), gentamicin-susceptible Enterobacterales (n=69), and gentamicin-resistant gram-negatives (n=16). Rates of postprocedural systemic inflammatory response syndrome (SIRS) were similar between P. aeruginosa and gentamicin-susceptible Enterobacterales groups (3.5% vs 4.3%; OR 0.80; p=1.00). Unplanned ICU admissions were also comparable (1.75% vs 1.4%). Culture-positive postoperative urine samples occurred in 26.3% vs 29.0% (OR 0.88; p=0.84), and symptomatic urinary or surgical site infections within 3 months occurred in 10.5% vs 17.4% (OR 0.56; p=0.32).

Postoperative bacteriuria was significantly higher in the gentamicin-resistant group compared to the P. aeruginosa group (62.5% vs 26.3%; OR 4.7; p=0.015). Gentamicin resistance among postoperative isolates remained low in targeted prophylaxis groups.

In conclusion, gentamicin prophylaxis showed comparable outcomes in P. aeruginosa (low MIC) and susceptible Enterobacterales, while use in resistant organisms was associated with worse outcomes.

Prescribing Inequities: Evaluating Under- and Over-Treatment Across Patient and Neighbourhood Factors

Presenter: Charlesnika Evans

This cross-sectional analysis evaluated disparities in antibiotic prescribing across 1,206,670 urgent care visits (January 2023–August 2025) in an academic healthcare system. Overall, 31.1% of visits resulted in an antibiotic prescription, varying by diagnosis tier: 59.9% (Tier 1: almost always indicated), 49.6% (Tier 2: sometimes indicated), and 14.6% (Tier 3: not indicated). Under-treatment (no antibiotic when indicated) was more likely among Black (aOR 1.49; 95% CI: 1.39–1.61), Asian/Pacific Islander (aOR 1.26; 95% CI: 1.15–1.39), and Hispanic patients (aOR 1.16; 95% CI: 1.08–1.26), as well as those with Medicare insurance (aOR 1.11; 95% CI: 1.02–1.19).

Minoritized patients also had lower odds of receiving unnecessary antibiotics compared to White patients, while non-Hispanic patients had higher odds (aOR 1.24; 95% CI: 1.18–1.31). Living in disadvantaged areas (aOR 1.08; 95% CI: 1.01–1.16) and higher comorbidity burden (aOR 1.06 per point; 95% CI: 1.06–1.07) were associated with slightly higher odds of unnecessary prescribing.

Overall, both under-treatment and over-prescribing disparities were observed across patient and neighbourhood factors.

Understanding What Matters to Patients in Antimicrobial Stewardship in Hospitals: A Mixed-Method Study

Presenter: Benson Jacob

This mixed-method study evaluated hospitalized patients’ knowledge, understanding, and expectations regarding antimicrobial use and antimicrobial stewardship (AMS) in a 1000-bed academic hospital. A total of 360 patients across six clinical groups participated in a 42-item questionnaire, followed by interviews with 36 patients. Awareness of antimicrobial resistance (AMR) was moderate (63.6%), while AMS awareness was very low (10.6%). Education was a significant predictor of both awareness and knowledge (β=0.072; p<0.001), whereas clinical group and current antibiotic use were not. Patients generally demonstrated responsible antibiotic behaviors, but preferences for advice and expectations varied across groups. Knowledge of diagnostic testing was limited, likely due to inconsistent communication from healthcare providers.

Qualitative findings showed that patient engagement was influenced by reliance on providers, lack of encouragement to ask questions, time constraints, and variable communication practices. Patients expressed a need for standardized and accessible information on AMR and AMS.

Overall, patient education, communication, and beliefs were key factors influencing engagement with antimicrobial stewardship.

Beyond the Algorithm: Human Factors Driving AI-Adoption in Antimicrobial Stewardship (AMS)

Presenter: Daphne Yii

This qualitative study explored physician perceptions of artificial intelligence (AI) in antimicrobial stewardship (AMS), using the AI²D model for suspected lower respiratory tract infections (LRTIs) as a case example. Eleven focus group discussions with 50 physicians across specialties were conducted using frameworks including Non-adoption, Abandonment and challenges to Scale-up, Spread and Sustainability of technology (NASSS) and Theoretical Domains Framework (TDF). Trust emerged as the dominant theme. Beyond scientific evidence, trust in AI was influenced by peer experiences and social validation. Physicians expressed both concerns and optimism—while worried about over-reliance and loss of clinical judgement, they believed AI could enhance decision-making and improve physician–patient interactions by reducing cognitive burden.

Participants emphasized that AI should complement, not replace, clinical expertise, supporting a “human-in-the-loop” approach where physicians retain final decision-making authority. Key facilitators for adoption included seamless system integration and leadership support, while barriers included high workload and low AI literacy.

Successful AI implementation in AMS depends on trust, human-centered design, and institutional support alongside technical performance.

Top of Form

Knowledge and Attitudes of Allied Healthcare Professionals Towards Antibiotic Use and Antimicrobial Resistance: Questionnaire-Development and A Quantitative, Cross-Sectional Study

Presenter: Márió Gajdács

This cross-sectional study assessed antimicrobial resistance (AMR)-related knowledge, attitudes, and understanding among allied healthcare professionals (AHCPs) in Hungary. A total of 255 participants completed an 80-item online questionnaire conducted between March 2021 and March 2022. Most participants were female (90.2%) and nearly half worked in inpatient care (47.8%). While 95.7% were familiar with the term “antibiotic resistance,” understanding of more specific concepts was limited, with only 43.5% recognizing “biofilm” and 18.8% “MIC value.” Health-related studies were the main source of AMR knowledge (69.0%).

Higher self-rated academic performance was associated with better knowledge (19.58±5.37 vs 16.39±5.42; p<0.001), more favorable attitudes (10.53±3.06 vs 8.36±2.66; p<0.001), and greater recognition of AMR-related terms (5.37±1.95 vs 4.70±1.55; p=0.01). Age, work experience, health status, and qualification level did not significantly influence AMR competencies.

Overall, gaps exist in AMR-related knowledge among AHCPs, highlighting the need for targeted education.

"Bacteria And the Resistance": A Microbial Comic Book

Presenter: Gilbert Greub

This project explores the use of a comic book as a tool to communicate complex microbiology concepts, particularly antimicrobial resistance (AMR), to lay audiences. Using narrative storytelling and visual metaphors, the comic introduces readers to bacterial evolution, diversity, and survival strategies, guided by LUCA (Last Universal Common Ancestor). Scientific concepts are simplified through relatable imagery, such as bacterial defenses depicted as “armour,” biofilms as “fortresses,” dormant bacteria as “Sleeping Beauty,” and immune cells as “policemen.” These approaches aim to make invisible biological processes more understandable.

The comic effectively illustrates how antibiotic resistance develops and spreads, raising awareness in an engaging and non-alarmist manner. By combining storytelling, humor, and visuals, it enhances comprehension and retention across audiences.

Overall, the project highlights the potential of comics as an effective educational tool for improving public understanding of AMR.

A Case Study on Effective Student Engagement in Antimicrobial Resistance: The Makerere University AMR Club Model

Presenter: Vivian Nabisere

This descriptive case study evaluated the Makerere University Antimicrobial Resistance Club (MUAC), established in 2023 to strengthen AMR awareness and action through structured student participation, interdisciplinary collaboration, and faculty mentorship. The analysis was based on activity reports, internal monitoring data, and documentation of partnerships and outreach activities from 2023 to 2025. Key areas assessed included governance, programming, faculty involvement, community engagement, and resource mobilisation. MUAC implemented an inclusive governance structure with representation from all nine university colleges, supported by sustained faculty involvement for technical guidance and programme quality. The club conducted diverse activities, including eight educational webinars, creative competitions, digital awareness campaigns, and school and community outreach.

Strategic partnerships were established with academic departments, international organisations, and local community groups. Within two years, MUAC directly reached over 20,000 individuals and secured six national and international grants and awards. Additional outcomes included the development of AMR awareness platforms in primary and secondary schools, creation of culturally adapted educational materials in local languages, and participation in international forums representing student perspectives.

Overall, the MUAC model demonstrates a structured and scalable approach to integrating students into AMR initiatives at institutional and national levels.

A Multi-Seasonal Mixed-Method Point-Prevalence Study of Antibiotic Prescription Patterns in a Tertiary Healthcare Facility in India

Presenter: Arunima Mukherjee

This multi-seasonal mixed-method point prevalence survey (PPS) evaluated antibiotic prescribing patterns and influencing factors in a northern Indian tertiary-care hospital between November 2023 and January 2025. Data were collected across four seasons from five inpatient departments, combining quantitative prescribing data with qualitative ward observations. A total of 1,680 inpatients were included. The most commonly prescribed antibiotics were ceftriaxone (30–33%), piperacillin–tazobactam (9–20%), and doxycycline (8–16%). Azithromycin use declined after the first phase, while amikacin (6–9%) and meropenem (4–7%) use remained low. Empirical prescribing was high (63–67%), with culture-guided therapy ≤6%. Over 80% of antibiotics were administered parenterally. Watch antibiotics accounted for 46–56% of prescriptions, Access antibiotics 35–51%, and Reserve antibiotics ≤4%. Prophylactic use ranged from 24–30%, and combination therapy was common in ICU settings. Seasonal variation was observed, with gastrointestinal (20–22%) and chronic conditions (17–23%) most frequent, and respiratory infections peaking during monsoon and winter (3–9%). Antibiotic modifications following antimicrobial susceptibility testing (AST) were low (4.7–6.5%).

Qualitative findings identified oral antibiotic stock-outs, delays in culture sampling, and poor documentation during patient transfers as key contributors to continued empirical and broad-spectrum antibiotic use.

The study highlights high empirical prescribing, limited use of culture-based guidance, and system-level gaps affecting antimicrobial stewardship.

Epidemiological Patterns of Carbapenem Resistance in Solid Organ Transplantation: A Contemporary Multi-Centre Analysis

Presenter: Ayse Hande Arslan

This multicentre retrospective study evaluated epidemiological patterns of carbapenem-resistant Gram-negative (CRGN) infections across solid organ transplant (SOT) recipients.

A total of 460 CRGN infection episodes (2014–2023) from seven transplant centres were analysed. The most common pathogens were Klebsiella spp (47%), followed by Acinetobacter spp (27%) and E. coli (13.7%). Considerable inter-centre variability was observed in pathogen distribution, diagnostics, and prophylaxis practices. Only two centres performed routine pre-transplant rectal screening.

Kidney transplant recipients accounted for ~65% of infections. Urinary tract infections were the most frequent overall. Liver recipients had higher rates of early (<3 months) and severe infections, particularly bloodstream and respiratory infections, often linked to ICU-associated Acinetobacter. In heart and combined kidney–liver transplants, wound/tissue infections were more common, suggesting surgical site involvement.

Two key clinical pathways were identified: early urinary Klebsiella infections in kidney recipients, and late ICU-associated respiratory Acinetobacter infections linked with higher mortality.

Thirty-day mortality was 25.9%, and ninety-day mortality was 32.6%, with the highest mortality seen in ICU-associated respiratory infections and early bloodstream infections in liver recipients. Overall, CRGN infections showed distinct patterns based on organ type, timing, and care setting.

Aztreonam/Avibactam Resistance Due To Synergistic Interplay of ampC-Related Mutations in Carbapenem-Resistant Enterobacter Spp.

Presenter: Yang Zeng

This study investigated resistance mechanisms to aztreonam-avibactam (ATM-AVI) in metallo-β-lactamase-producing Enterobacter xiangfangensis. ATM-AVI-resistant mutants were generated through induction experiments, followed by genome sequencing and expression analysis. Four resistant mutants were identified.

All mutants harboured ampC mutations causing amino acid substitutions at position 150 (Tyr150Cys or Tyr150Ser), along with ampD mutations leading to either amino acid substitution (Cys108Tyr) or truncation (Glu106X, Trp95X). Two mutants also had mutations in the ampC attenuator region.

Minimum inhibitory concentration (MIC, mg/L) increased progressively with combined mutations:

AmpC (Tyr150Ser) + AmpD (Glu106X): 32/4
AmpC (Tyr150Cys) + AmpD (Cys108Tyr): 64/4
AmpC (Tyr150Cys) + AmpD (Cys108Tyr) + attenuator (+13G>T): 256/4
AmpC (Tyr150Cys) + AmpD (Trp95X) + attenuator (+7T>C): 256/4

Individually, AmpC substitution or ampD mutation reduced susceptibility, but combined mutations conferred resistance. Attenuator mutations increased ampC expression by 2–4 fold, further elevating resistance levels. Overall, resistance was driven by a combination of structural changes in AmpC, regulatory gene mutations, and increased gene expression.

Antimicrobial Stewardship Implementation Across Intensive Care Units: Insights from A National Survey

Presenter: Anna Marthe Van Boekel

This national survey evaluated the implementation and structure of antimicrobial stewardship programs (ASPs) across ICUs in the Netherlands.

A total of 213 respondents from 69 hospitals (100% hospital-level response) participated. ICU sizes were 4–9 beds (36%), 10–19 beds (41%), and ≥20 beds (23%). ASPs were reported in 100% of ICUs; however, only 45% were formally organized, while 55% had informal implementation of ASP elements.

Common AMS protocols included perioperative prophylaxis (~90%), therapeutic drug monitoring (~85%), initiation of antimicrobial therapy (~85%), IV-to-oral switch (~80%), optimisation/de-escalation (~70%), and stopping therapy (~60%).

Antimicrobial restriction strategies were implemented in all ICUs, most commonly via post-authorization review (~75%), post-prescription review (~60%), and automatic alerts (~30%). Other approaches included pre-authorization (~30%), post-authorization first prescription (~35%), and indication forms (~25%). Overall, while AMS interventions were universally present, there was substantial variability in the type, number, and level of formalization of ASPs across ICUs.

Optimising Intravenous to Oral Antibiotic Switch in Intensive Care Units: A Multi-Site Audit Using UKHSA IVOS Criteria Across Three West Midlands NHS Trusts

Presenter: Nirlep Agravedi

This multi-site audit evaluated IV-to-oral switch (IVOS) practices in ICU patients across three NHS Trusts using UKHSA criteria.

A total of 37 patients were assessed (MMUH (Midland Metropolitan University Hospital) n=11, Dudley n=10, QEH (Queen Elizabeth Hospital) n=16). Overall, only 21.6% (8/37) of patients were switched or eligible for IV-to-oral conversion, with variation across sites (QEH 37.5%, Dudley 20.0%, MMUH 9%).

Adherence to individual IVOS criteria varied: safe swallow (81.1%), absence of vomiting (97.3%), and temperature stability (75.7%) were commonly met, whereas clinical improvement (59.5%) and adequate gastrointestinal function (59.5%) were less frequent.

Special infection considerations requiring prolonged IV therapy were present in 67.6% of patients. Key barriers to IVOS included clinical deterioration and gastrointestinal dysfunction. Overall, IV-to-oral switch rates were suboptimal, with notable inter-site variation, highlighting the need for more consistent assessment practices.

Epidemiology of Penicillin-Binding Protein 3 Variants in Carbapenem-Resistant Escherichia coli Isolates from France

Presenter: Imene Mehidi

This genomic study analysed 1,837 Escherichia coli isolates (July 2023–October 2024) to investigate penicillin-binding protein 3 (PBP3) alterations and their association with carbapenem resistance. PBP3 modifications were identified in 64.9% (1,189/1,837) of isolates, with 56 polymorphisms detected. The most common changes were two amino acid substitutions (56.7%; n=674) and four–amino acid insertions (33.8%; n=402) at positions 331–334, resulting in YRIN, YRIK, or YTIP duplications. The predominant carbapenemases were OXA-244 (27.8%) and NDM-5 (26.3%). High-risk sequence types included ST38 (22.3%), ST410 (10.3%), and ST167 (6.9%). Common resistance genes included CTX-M-15 (66.5%) and CMY-2 (8.5%).

Isolates with PBP3 insertions showed reduced susceptibility to last-line antibiotics: 98.9% had cefiderocol MICs >2 µg/mL, and 22.36% had aztreonam/avibactam MICs ≥4 µg/mL.

Overall, PBP3 insertions, often linked with NDM enzymes and high-risk clones, contribute to increasing resistance and reduced efficacy of key antibiotics.

Molecular Antimicrobial Resistance Gene Profiles in Community-Acquired, Healthcare-Associated, and Hospital-Onset E. Coli and K. Pneumoniae Bacteraemia

Presenter: Leyla Genç

This prospective study evaluated resistance determinants in Escherichia coli and Klebsiella pneumoniae bloodstream infections across community-acquired (CAB), healthcare-associated (HCAB), and hospital-onset bacteremia (HOB) between June and November 2025. A total of 142 isolates were collected, of which 77 resistant isolates underwent molecular analysis. In E. coli, ESBLs—mainly blaCTX-M—and AmpC were widespread across groups, while carbapenemases (blaNDM, blaOXA-48) and plasmid-mediated quinolone resistance (qnrS1) were detected only in HCAB and HOB. Aminoglycoside resistance determinants were also concentrated in HCAB.

K. pneumoniae showed a higher and broader multidrug-resistant profile, including widespread ESBLs, PMQR genes, multiple aminoglycoside resistance determinants, and double carbapenemase production (NDM + OXA-48).

Overall, resistance burden followed a gradient (HOB > HCAB > CAB), with K. pneumoniae demonstrating the highest resistance across all categories.

PathCrisp: A Next-Generation CRISPR Diagnostic Platform for Rapid Detection of Antimicrobial Resistance

Presenter: Mandar Prakash Naik

This study evaluated PathCrisp, a CRISPR-based diagnostic platform designed for rapid detection of pathogens and antimicrobial resistance (AMR) markers. The system integrates PCR-based amplification with Cas12-mediated detection and supports fluorescence, visual, and lateral flow readouts for both laboratory and point-of-care use. The PathCrisp-TyphoidDetect panel was developed to identify Salmonella species (S. Typhi, S. Paratyphi) and key AMR genes (NDM, CTX-M, SHV). Analytical validation using positive blood culture bottles showed 100% concordance with comparator PCR and standard culture methods. The limit of detection ranged from 1–10 cells/µL. The assay generated results within ~2 hours after blood culture positivity, significantly faster than conventional diagnostics (18–24 hours). Lyophilized reagents maintained performance, supporting use in resource-limited settings.

Additional panels under development include detection of carbapenemases (NDM, OXA, VIM, KPC, IMP), ESBL genes, and other pathogens.

Overall, PathCrisp demonstrated rapid, accurate, and field-adaptable detection of pathogens and AMR markers.

MIC Creep in the Shadows: An Interactive Dashboard for Forecasting MIC Trends in Newer antimicrobials against MDR pathogens across WHO regions

Presenter: Neha Nityadarshini

This study evaluated temporal trends and forecasts of minimum inhibitory concentrations (MICs) for newer antibiotics against carbapenem-resistant pathogens using 49,758 isolates from global datasets (Pfizer-ATLAS, SIDERO-WT, IST-Entesis). Eight drug–pathogen combinations were analysed, including Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Resistance metrics included % resistance, log2MIC, MIC50, and MIC90, with forecasts generated for five years.

In 2023, E. coli–ceftazidime-avibactam (CZA) and E. coli–meropenem-vaborbactam (MPV) showed the highest global resistance. The Southeast Asia region had the highest burden for multiple combinations, including KP-MPV and PA-ceftolozane-tazobactam.

E. coli–CZA showed the fastest increase in log2MIC globally and in the Americas. Forecasts indicated that E. coli–MPV and K. pneumoniae–CZA may exceed clinical breakpoints within five years. In contrast, A. baumannii–sulbactam-durlobactam and –cefiderocol remained within safe MIC ranges. Wider uncertainty was noted for MPV combinations due to limited data.

The study highlights emerging MIC increases in key drug–pathogen pairs and regional variation in resistance trends.

NANOMUR: Innovative Nanomotion Technology for Antibiotic Susceptibility Testing: A Game-Changer for Urinary Tract Infections?

Presenter: Alexandre Delfino

This study evaluated an innovative nanomotion-based approach combined with machine learning (ML) to accelerate antibiotic susceptibility testing (AST) for urinary tract infections, aiming to overcome delays associated with culture-based methods.

A total of 81 monomicrobial urine samples were analysed. Initial evaluation using a model trained on spiked blood samples showed 82.72% (67/81) accuracy, 85.92% (61/71) sensitivity, and 60% (6/10) specificity. When models were trained directly on urine sample data, performance improved significantly. The best-performing model, a multilayer perceptron, achieved 95.06% accuracy, 97.18% sensitivity, and 80% specificity.

Nanomotion markedly reduced diagnostic turnaround time, delivering results in a median of 4.4 hours, compared with 37.5 hours using routine diagnostics (culture and VITEK2).

Overall, nanomotion demonstrated strong diagnostic performance and a substantial reduction in time-to-results when combined with optimized ML models.

Not All MIC Plates Are Equal: Method-Driven Shifts in Cefiderocol Susceptibility for NDM-Producing Enterobacterales

Presenter: Mélanie Bouillon

This study compared two methods for determining cefiderocol minimum inhibitory concentrations (MICs) in NDM-producing Enterobacterales (EBNDM), where accurate susceptibility testing is critical for treatment decisions. A total of 29 isolates across 8 species were analysed, including 21 ESBL-producing strains. MICs were measured using a commercial UMIC® assay and an in-house broth microdilution (BDM) method.

Results:

MIC50: 4 mg/L (UMIC) vs 2 mg/L (BDM)
MIC90: 8 mg/L for both methods
EUCAST susceptibility: 48% (UMIC) vs 72% (BDM)
CLSI susceptibility: 83% (UMIC) vs 86% (BDM)

A consistent discrepancy was observed for all NDM-7 isolates (n=3). Overall agreement between methods was 48%, with a kappa coefficient of 0.34, indicating low concordance. No specific resistance profile or strain type explained the variability.

Overall, significant differences between testing methods may impact clinical interpretation of cefiderocol susceptibility.

Rethinking ESBL Detection in Enterobacterales: Comparison if EUCAST And CLSI Guidelines and Development of a Clavulanate-Free Algorithm

Presenter: Linea Katharina Muhsal

This study compared EUCAST and CLSI methods for detecting ESBLs in Enterobacterales using whole genome sequencing (WGS) as the reference standard and evaluated a new machine learning–based algorithm.

A total of 231 isolates were analysed.

CLSI CDT: sensitivity 80.3% (CI 72.2–87.0%), specificity 62.2% (CI 44.8–77.5%) across four species
EUCAST CDT: sensitivity 42.7% (CI 34.6–51.0%), specificity 91.4% (CI 83.0–96.5%)
Restricting EUCAST to the same species slightly improved sensitivity to 47.5% with specificity 83.8%

Proteus mirabilis was particularly challenging due to apparent ceftazidime susceptibility despite ESBL presence.

A new clavulanate-free algorithm based on ceftazidime, cefepime, and cefoxitin achieved: