Relative faecal abundance to predict extended-spectrum β-lactamase-producing Enterobacterales related ventilator‑associated pneumonia

(2025) 15:34 Bay et al. Annals of Intensive Care https://doi.org/10.1186/s13613-025-01456-w Annals of Intensive Care Open Access RESEARCH Relative faecal abundance to predict extended‑spectrum β‑lactamase‑producing Enterobacterales related ventilator‑associated pneumonia Pierre Bay1,2,3* , Paul‑Louis Woerther4,5, Vincent Fihman4, Ségolène Gendreau1,2, Pascale Labedade1,2, Antoine Gaillet1,2, Florian Jolly1,2, Guillaume Carteaux1,2, Nicolas de Prost1,2,3, Jean‑Winoc Decousser4,5, Armand Mekontso‑Dessap1,2 and Keyvan Razazi1,2 Abstract Background Antimicrobial stewardship (AMS) for ventilator-associated pneumonia (VAP) in carriers of extendedspectrum β-lactamase-producing Enterobacterales (ESBL-E) presents significant challenges. The abundance of ESBL-E rectal carriage has emerged as a potentially valuable tool for predicting ESBL-E-related VAP. Methods This single-center, retrospective study was conducted between October 2019 and April 2023 in the medi‑ cal ICU of a university hospital. The relative abundance of ESBL-E rectal carriage (RAC) was calculated as the ratio of ESBL-E counts to the total number of aerotolerant bacteria. The aim was to evaluate the predictive value of RAC for diagnosing ESBL-E-related VAP in patients with confirmed VAP who were ESBL-E carriers. Results During the study period, 478 patients with ESBL-E carriage were admitted to the ICU, of whom 231 (48%) required mechanical ventilation. Eighty-three patients (17%) developed a total of 131 confirmed VAP episodes, of which 62 episodes (47%) were ESBL-E-related VAP. The median interval between the last rectal screening and VAP occurrence was 4 [3–7] days. RAC was not associated with ESBL-E-related VAP in the entire cohort (p = 0.39). Similar findings were observed in several sensitivity analyses, including the following subsets: recent and high-quality screen‑ ing (interval between screening and VAP ≤ 7 days and bacterial load on rectal swab > 104 CFU/mL, p = 0.21); first VAP episodes only (p = 0.41); cases involving Escherichia coli exclusively (p = 0.08) or other ESBL-E strains (p = 0.29); and VAP associated with Gram-negative bacteria (p = 0.26) or Enterobacterales (p = 0.34). However, in a multivariable model, rec‑ tal colonization with non-Escherichia coli ESBL strains was independently associated with ESBL-E-related VAP (adjusted odds ratio [aOR] 1.213 [95% CI 1.005–1.463], p = 0.045). Conclusion RAC was not associated with confirmed VAP in ESBL-E carriers. Further studies are needed to explore effective strategies for improving AMS in ESBL-E carriers with suspected VAP. *Correspondence: Pierre Bay Full list of author information is available at the end of the article © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Bay et al. Annals of Intensive Care (2025) 15:34 Introduction Rational antimicrobial stewardship (AMS) in the intensive care unit (ICU) requires balancing the need for an early and adequate antibiotic regimen against the risk of promoting multidrug-resistant (MDR) bacteria through unnecessary broad-spectrum antibiotic use [1]. AMS poses particular challenges in patients colonized with extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), a known risk factor for ESBL-E-related infections. Ventilator-associated pneumonia (VAP) is the most common ICU-acquired infection [2]. French guidelines recommend carbapenem use for suspected VAP in ESBL-E-colonized patients who are immunosuppressed or exhibit severe infection [3]. However, ESBL-E-related VAP accounts for only 7% of infection-related ventilator-associated complications in carriers [4]. Importantly, ESBL-E rectal carriage is a well-recognized driver of carbapenem overuse in the ICU [5, 6], emphasizing the need for novel diagnostic strategies in ESBL-E carriers with suspected VAP. Several studies have demonstrated that intestinal colonization with ESBL-E is a prerequisite for the development of ESBL-E infections [7, 8]. Research that defines the relative abundance of ESBL-E as the ratio of ESBL Enterobacterales to the total Enterobacterales count in stool samples suggests that the relative or absolute abundance of ESBL-E in the gut may enhance risk assessment for ESBL infections in carriers [9, 10]. The hypothesis of this study was that the relative abundance of ESBL-E rectal carriage (RAC), calculated as the ratio of ESBL-E counts to the total number of aerotolerant bacteria, on the last rectal swab prior to the onset of VAP would be associated with the ESBL-E status of VAP and could serve as an effective tool to guide empiric antibiotic therapy in cases of suspected VAP in ESBL-E carriers. The primary aim of this study was to evaluate the performance of RAC in diagnosing confirmed ESBL-Erelated VAP in ESBL-E carriers. The secondary aim was to identify factors associated with ESBL-E-related VAP in ESBL-E carriers. Methods Settings and patients This single-center, retrospective study was conducted between October 2019 and April 2023 in the medical ICU of a university hospital that did not used selective digestive decontamination (SDD). All confirmed VAP episodes in ESBL-E carriers were included. Data collected included age, sex, comorbidities, Simplified Acute Physiology Score (SAPS II), primary reason for admission, antibiotic classes administered during the ICU stay, Page 2 of 12 clinical and biological factors at the time of respiratory sampling, and characteristics of ESBL-E carriage. Definitions Confirmed VAP was defined as clinical suspicion of VAP combined with a positive quantitative culture from a respiratory sample. VAP was clinically suspected after 48 h of mechanical ventilation in the presence of new or persistent pulmonary infiltrates on chest X-ray, along with at least two of the following classical signs: purulent tracheal secretions, fever or hypothermia (body temperature ≥ 38.5 °C or ≤ 36.5 °C), leukocytosis or leukopenia (white blood cell count ≥ 12 × 10⁹/L or ≤ 4 × 10⁹/L) [4, 11, 12]. VAP confirmation required a quantitative culture [12] from one of the following samples: protected telescopic catheter (≥ 103 CFU/mL), bronchoalveolar lavage fluid (≥ 104 CFU/mL), or endotrachea (...truncated)