Francisco Javier Candel

Background/Objectives: Stenotrophomonas maltophilia is a common cause of lower respiratory tract infection (LRTI) in critically ill patients, but differences between ventilator-associated tracheobronchitis (VAT) and ventilator- or hospital-acquired pneumonia (VAP/HAP) remain unclear. We aimed to compare clinical outcomes between VAT and VAP/HAP and, secondarily, to explore antimicrobial treatment patterns and their association with treatment failure. Methods: We conducted a retrospective two-center cohort study of adults admitted to intensive care units (ICUs) in Madrid, Spain, between August 2021 and December 2025 with clinically significant S. maltophilia VAT, VAP, or HAP. The primary analysis included only the first (index) episode per patient. Results: Sixty-seven patients contributed 90 episodes. Among index episodes, therapeutic failure was more frequent in VAP/HAP than in VAT (40.6% vs. 14.3%; absolute risk difference, 26.3 percentage points; 95% confidence interval [CI], 5.0–45.2; p = 0.026). In a parsimonious Firth’s penalized logistic regression, VAP/HAP remained associated with therapeutic failure (adjusted odds ratio, 4.06; 95% CI, 1.32–14.25; p = 0.014). Results were consistent after adjustment for SOFA score at infection onset and when the analysis was restricted to VAP. ICU mortality was numerically higher in VAP/HAP (46.9% vs. 25.7%). In an exploratory Firth’s model, laboratory-reported in vitro active antimicrobial therapy was associated with lower odds of failure (adjusted odds ratio, 0.19; 95% CI, 0.05–0.72; p = 0.014); however, this exposure was susceptible to time-dependent bias, and empirical anti-S. maltophilia therapy, defined at treatment initiation, was not associated with failure (26.7% vs. 26.9%). Conclusions: The clinical and prognostic significance of respiratory S. maltophilia infection appears to differ by syndrome. VAP/HAP was associated with more therapeutic failure than VAT. The association between in vitro active therapy and lower failure was exploratory and requires confirmation, and no comparative effectiveness conclusions can be drawn for individual antimicrobial agents.

Background: Tetracyclines remain useful options for Gram-positive infections, particularly when prolonged oral therapy is required. Doxycycline is attractive because of its oral bioavailability and tolerability, but many susceptibility systems report tetracycline or minocycline rather than doxycycline, creating uncertainty about within-class extrapolation. Objectives: To examine the microbiological, pharmacokinetic/pharmacodynamic (PK/PD), interpretive and clinical evidence supporting cross-susceptibility among tetracycline-class agents in clinically relevant Gram-positive organisms and to define when surrogate results may reasonably support doxycycline use. Methods: We performed a narrative review of PubMed/MEDLINE and ScienceDirect (1990–2025), supplemented by current European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) documents. Predefined search concepts covered resistance mechanisms, cross-susceptibility, PK/PD and clinical outcomes. Primary microbiological, surveillance, PK/PD and clinical studies and systematic reviews/meta-analyses were prioritized. Results: Cross-susceptibility is not uniform across the tetracycline class. Efflux mechanisms such as tet(K) and tet(L) may permit retained doxycycline or minocycline activity, whereas ribosomal protection mechanisms such as tet(M) and tet(O) are associated with broader reduced susceptibility. Interpretation is organism-, phenotype-, method- and breakpoint-dependent. Free-drug Area Under the Concentration-Time Curve (AUC)/Minimun Inhibitory Concentration (MIC) is the principal PK/PD index, but exposure targets vary by agent, pathogen, model and endpoint. Direct clinical evidence is heterogeneous and is strongest for selected staphylococcal osteoarticular infections and suppressive therapy. Conclusions: Organism-specific EUCAST or CLSI surrogate rules may provide sufficient microbiological support for doxycycline use without routine agent-specific MIC confirmation when the clinical context is appropriate. Direct doxycycline testing is particularly valuable when surrogate interpretation is unsupported, results are resistant or discordant or uncertainty could materially affect management of severe or deep-seated infection.

Background: Antimicrobial resistance (AMR) is a major global health threat with substantial clinical and economic consequences. However, robust national estimates of the economic burden of AMR-related hospitalizations to AMR remain limited. We aimed to quantify the hospitalization costs attributable to AMR in Spain and to assess their variation across infection types. Methods: We conducted a nationwide, retrospective cohort study using the Spanish Specialized Care Activity registry. We included all adult hospitalizations with a diagnosis of bacterial infection between 1 January 2017, and 31 December 2022. Antimicrobial resistance was defined using International Classification of Diseases, 10th Revision, Clinical Modification resistance diagnosis codes. Hospitalization costs were estimated using nationally standardized All Patient Refined Diagnosis-Related Groups cost weights. Generalized linear models were used to estimate the incremental cost associated with AMR after adjustment for demographic and clinical characteristics. Results: Among 2 817 406 hospitalizations with bacterial infection, 175 188 (6.22%) involved AMR. In adjusted analyses, AMR was associated with a 15% increase in hospitalization costs (cost ratio 1.15, 95% confidence interval [CI] 1.15–1.16; P < .0001), corresponding to an incremental cost of euros (EUR) 925 (95% CI 887–962) per hospitalization. The cost of hospitalizations with bacterial AMR infections was EUR 215 million annually (95% CI 213.33–216.67). After adjustment for patient and clinical characteristics, the attributable economic burden of AMR was EUR 27.10 million annually. This economic impact of AMR varied substantially across infection types, with the greatest attributable economic burden intra-abdominal infections, acute pyelonephritis, pneumonia, and lower urinary tract infections. Conclusions: In this nationwide cohort, AMR was independently associated with an increase in hospitalization costs in Spain, contributing meaningfully to national healthcare expenditure.

At a time of great concern regarding trends in morbidity and mortality from infections, and mindful of the limitations of our current approaches to combating them, this document sets out a structured programme of proposals aimed at improving, in the short and medium term, the survival of the most at-risk patients with severe infections. These are complementary proposals which, on the one hand, reinforce already established initiatives and, on the other, introduce some novel aspects to the approach to this complex problem. They focus on accelerating, standardising, and refining the clinical diagnosis of severe infection and its microbiological diagnosis and, above all, on improving the effectiveness of antimicrobial treatment, based on its immediate initiation with the most effective treatment available, and with an improved capacity to integrate innovation into all stages and processes. This programme is designed to be implemented within the framework of the Antimicrobial Stewardship Programmes (ASPs) (hence the name ASP-COMPLEX), and requires appropriate dissemination and surveillance policies, alongside a collaborative environment among the multiple stakeholders involved in delivering innovation (experts, ASP teams, healthcare administration, academia, the pharmaceutical industry, etc.).

Pneumonia is the leading cause of death from infection in the developed world. In recent years, researchers and healthcare professionals have worked tirelessly to address this issue. Multiresistance is a significant problem in severe pneumonia, so it is crucial to select the appropriate antibiotic at the correct dose and via the appropriate route of administration to ensure effective concentrations in the lung parenchyma. The diagnosis of pneumonia can also be challenging, so it is vital that imaging techniques, biomarkers, and microbiological methods are employed properly. An appropriate therapeutic approach is vital for managing severe community-acquired pneumonia, as it can be complex and is key to achieving optimal clinical outcomes. Nosocomial pneumonia also requires optimal management to avoid therapeutic failure and to improve outcomes, particularly in post-surgery patients. Not only bacteria, but also viruses and fungi can cause severe pneumonia, and appropriate diagnosis is essential for proper treatment. Finally, the correct use of new antimicrobial molecules can help to improve the clinical outcomes of these patients. To provide an update on these issues, a multidisciplinary team of Spanish experts met at the Seventh Annual Pneumonia Day Meeting, which was sponsored by the Grupo de Estudio de Infección en el Paciente Crítico (GEIPC) of the Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica (SEIMC). This paper summarises the discussions held at the meeting and offers the latest insights on these topics, providing guidance on overcoming the challenges associated with pneumonia management.

Revista Española de Quimioterapia tiene un carácter multidisciplinar y está dirigida a todos aquellos profesionales involucrados en la epidemiología, diagnóstico, clínica y tratamiento de las enfermedades infecciosas. Fundada en 1988 por la Sociedad Española de Quimioterapia.

The spread of metallo-β-lactamases (MBL)-producing Gram-negative bacilli represents a global health challenge, associated with increased mortality rates. The prevalence of MBL-producing isolates, particularly of New Delhi metallo-β-lactamase (NDM) subclass, is increasing globally. The optimal antibiotic for infections depends on the species and MBL subclass produced. Currently, the antimicrobial cornerstones against these pathogens are aztreonam/avibactam and cefiderocol. Successful therapy requires the early and adequate initiation of antibiotic treatment, optimisation of its pharmacokinetics/pharmacodynamics, and appropriate control of the infection source.