Assessing the burden of antimicrobial resistance is essential to determine the magnitude of this problem and to set its priority. We aimed to estimate the burden of disease caused by multidrug-resistant microorganisms (MDRO) in hospitalised patients in Spain. Three prospective nationwide studies were conducted in 2018, 2019 and 2023. All patients with a new diagnosis of infection with any of 10 selected MDROs plus Clostridioides difficile during the study period (one week in 2018 and 2019 and two weeks in 2023) were included. Patient demographic, and clinical outcomes were analysed, including incidence, crude all-cause 30-day mortality and years of life lost (YLL). These results were used to calculate weighted and seasonally adjusted annual estimates for the whole country. In total, 82, 133 and 130 centres participated in the study in 2018, 2019 and 2023, respectively, recording a total of 907, 1392 and 2351 MDRO infections, representing a weighted incidence density of 3.54 (95% CI 2.92–4.17), 5.01 (3.95–6.07), and 4.41 (3.55–5.27) cases/1000 stays, respectively. A total of 161, 198 and 352 patients died with an MDRO infection, representing a weighted incidence density of 0.46 (0.16–0.76), 0.43 (0.17–0.69), and 0.62 (0.52–0.72) deaths/1000 stays, respectively. Based on these data, a nationwide occurrence of 155,294 MDRO infections (95% CI 127,928–182,569) with 20,065 deaths (6938–32,958) was estimated for 2018, 210,451 MDRO infections (165,963–254,975) with 17,982 deaths (7071–28,700) for 2019, and 173,653 MDRO infections (139,814–207258) with 24,582 deaths (20,461–28,796) for 2023. The burden of disease caused by MDRO infections among hospitalised patients in Spain is very high and remains stable over the study period. National actions to combat bacterial resistance need to be intensified. The management costs of this study were funded by the 10.13039/501100015756 Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC). Researchers have participated voluntarily and none of the investigators received funding for conducting the study.

VIM-type-producing Gram-negative bacteria (GNB) infections are difficult to treat. This is a retrospective single-center study of 34 patients who received cefiderocol for the treatment of VIM-type-producing GNB infections, including 25 Pseudomonas spp., 7 Enterobacterales, and 5 Achromobacter sp. Primary outcomes were clinical failure (defined as death, lack of clinical improvement, or a switch to another drug) at day 14 and 30-day all-cause mortality. The median age was 59 years (IQR 53.7–73.4), and the median Charlson comorbidity index was 3.5 (IQR 2–5). The main infections were respiratory tract infections (n = 9, 27%) and skin and soft tissue infections (n = 9, 27%). Eight patients exhibited bacteremia. In 9/17 patients with a drainable focus, drainage was performed. The median cefiderocol treatment duration was 13 days (IQR 8–24). Five patients (15%) experienced clinical failure on day 14, and the thirty-day mortality rate was 9/34 (27%); two cases occurred because of an uncontrolled infection source, and one was due to a new infection caused by the same bacteria. The other six deaths were unrelated to the index infection. Five patients experienced microbiological recurrence within three months. Susceptibility testing revealed the development of cefiderocol resistance in 1/7 cases with persistent or recurrent positive cultures. Cefiderocol, even in monotherapy, could be considered for the treatment of VIM-type-producing GNB infections.

Lung transplant recipients (LTR) are highly susceptible to Aspergillus infection (AI), but diagnosis may be limited by the invasiveness of bronchoalveolar lavage fluid (BALF) collection. Proximal airway samples may provide a less invasive alternative. We conducted a retrospective single-center study including all adult LTR (March 2018–March 2022) who underwent bronchoscopy with tracheobronchial aspirate (TBA) and BALF galactomannan (GM) testing in the same procedure. They were processed for mycological culture and EIA-based GM (Bio-Rad) after cysteine homogenization. AI was defined according to ISHLT consensus. A ROC curve for TBA GM and its diagnostic performance were assessed. A total of 545 paired TBA–BALF samples from 282 LTR were analyzed. Proven or probable AI was diagnosed in 22 samples (4%). The optimal TBA GM cut-off was ≥0.54 optical density index (ODI), yielding 95.2% sensitivity, 92% specificity, and an AUC of 0.97 (95% CI, 0.95–0.99). In comparison, BALF GM at ≥1.0 ODI showed 33.3% sensitivity and 99.6% specificity (AUC 0.88, 95% CI, 0.80–0.95) although BALF GM values were significantly higher in invasive infections compared with non-invasive infections (1.49 vs 0.14; P -value = 0.007). TBA cultures were more frequently positive than BALF (24% vs 9.9%). Finally, TBA and BALF GM values demonstrated moderate correlation ( r = 0.54), and combined testing with concordant results improved accuracy to 99.6%. TBA GM demonstrated higher sensitivity than BALF GM for detecting AI in LTR, while maintaining high specificity. Proximal airway samples could complement BALF in future diagnostic strategies. IMPORTANCE: This study provides evidence that galactomannan antigen testing (GM) in tracheobronchial aspirate (TBA) is a highly sensitive, reliable, and less invasive diagnostic tool for detecting Aspergillus infection in lung transplant recipients under universal antifungal prophylaxis, compared to the current standard bronchoalveolar lavage fluid (BALF) GM. These findings highlight the diagnostic value of proximal airway specimens, consistent with the pathophysiology of post-transplant aspergillosis, which often originates in the bronchial tree and may not be adequately captured by BALF early in the disease course. Importantly, the study shows that combining TBA and BALF GM results yields near-perfect diagnostic accuracy, supporting a complementary diagnostic strategy rather than a replacement approach. Although this is a proof-of-concept study, it fills a critical evidence gap in transplant infectious diseases and lays the groundwork for safer, more accurate, and earlier diagnosis of Aspergillus infection, with potential implications for clinical practice, antifungal stewardship, and future guideline development.