Serratia marcescens is an opportunistic pathogen historically associated with sudden outbreaks in intensive care units (ICUs) and the spread of carbapenem-resistant genes. However, the ecology of S. marcescens populations in the hospital ecosystem remains largely unknown. We combined epidemiological information of 1,432 Serratia spp. isolates collected from sinks of a large ICU that underwent demographic and operational changes (2019–2021) and 99 non-redundant outbreak/non-outbreak isolates from the same hospital (2003–2019) with 165 genomic data. These genomes were grouped into clades (1–4) and subclades (A and B) associated with distinct species: Serratia nematodiphila (1A), S. marcescens (1B), Serratia bockelmannii (2A), Serratia ureilytica (2B), S. marcescens / Serratia nevei (3), and S. nevei (4A and 4B). They may be classified into an S. marcescens complex (SMC) due to the similarity between/within subclades (average nucleotide identity >95%–98%), with clades 3 and 4 predominating in our study and publicly available databases. Chromosomal AmpC β-lactamase with unusual basal-like expression and prodigiosin-lacking species contrasted classical features of Serratia . We found persistent and coexisting clones in sinks of subclades 4A (ST92 and ST490) and 4B (ST424), clonally related to outbreak isolates carrying bla _VIM-1 or bla _OXA-48 on prevalent IncL/pB77-CPsm plasmids from our hospital since 2017. The distribution of SMC populations in ICU sinks and patients reflects how Serratia species acquire, maintain, and enable plasmid evolution in both “source” (permanent, sinks) and “sink” (transient, patients) hospital patches. The results contribute to understanding how water sinks serve as reservoirs of Enterobacterales clones and plasmids that enable the persistence of carbapenemase genes in healthcare settings, potentially leading to outbreaks and/or hospital-acquired infections. IMPORTANCE: The “hospital environment,” including sinks and surfaces, is increasingly recognized as a reservoir for bacterial species, clones, and plasmids of high epidemiological concern. Available studies on Serratia epidemiology have focused mainly on outbreaks of multidrug-resistant species, overlooking local longitudinal analyses necessary for understanding the dynamics of opportunistic pathogens and antibiotic-resistant genes within the hospital setting. This long-term genomic comparative analysis of Serratia isolated from the ICU environment with isolates causing nosocomial infections and/or outbreaks within the same hospital revealed the coexistence and persistence of Serratia populations in water reservoirs. Moreover, predominant sink strains may acquire highly conserved and widely distributed plasmids carrying carbapenemase genes, such as the prevalent IncL-pB77-CPsm (pOXA48), persisting in ICU sinks for years. The work highlights the relevance of ICU environmental reservoirs in the endemicity of certain opportunistic pathogens and resistance mechanisms mainly confined to hospitals.

Cefiderocol is a new siderophore cephalosporin with potent in vitro activity against gram-negative bacilli including Enterobacterales that produce all kinds of carbapenemases and non-fermenting Gram-negative with difficult-to-treat resistance. As a β-lactam, its efficacy is optimized in extended-perfusion and requires dose adjustment in renal dysfunction and hyperclearance. Its efficacy has been validated in three clinical trials, one of them in the treatment of hospital-acquired pneumonia and ventilator-associated pneumonia. The clinical trial aimed at difficult-to-treat gram-negatives achieved the clinical and microbiological target, but the increase in mortality observed in the cefiderocol arm makes it necessary to demonstrate efficacy in real clinical practice. Cefiderocol is a good option among the new β-lactams for the treatment of pneumonia caused by Gram-negative bacilli carbapenem-resistant.

Infections due to Klebsiella pneumoniae have been increasing in intensive care units (ICUs) in the last decade. Such infections pose a serious problem, especially when antimicrobial resistance is present. We created a task force of experts, including specialists in intensive care medicine, anaesthesia, microbiology and infectious diseases, selected on the basis of their varied experience in the field of nosocomial infections, who conducted a comprehensive review of the recently published literature on the management of carbapenemase-producing Enterobacterales (CPE) infections in the intensive care setting from 2012 to 2022 to summarize the best available treatment. The group established priorities regarding management, based on both the risk of developing infections caused by K. pneumoniae and the risk of poor outcome. Moreover, we reviewed and updated the most important clinical entities and the new antibiotic treatments recently developed. After analysis of the priorities outlined, this group of experts established a series of recommendations and designed a management algorithm.

The recent European Confederation of Medical Mycology (ECMM) and the International Society for Human and Animal Mycology (ISHAM) 2020 consensus classification proposes criteria to define coronavirus 2019 (COVID-19)-associated invasive pulmonary aspergillosis (CAPA), including mycological evidence obtained via non-bronchoscopic lavage. Given the low specificity of radiological findings in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, this criterion makes it difficult to differentiate between invasive pulmonary aspergillosis (IPA) and colonization. This unicenter and retrospective study includes 240 patients with isolates of any Aspergillus species in any respiratory samples during a 20-month study (140 IPA and 100 colonization). Mortality was high in the IPA and colonization groups (37.1% and 34.0%, respectively; p = 0.61), especially in patients with SARS-CoV-2 infection, where mortality was higher in colonized patients (40.7% vs. 66.6.%; p: 0.021). Multivariate analysis confirmed the following variables to be independently associated with increased mortality: age > 65 years, acute or chronic renal failure at diagnosis, thrombocytopenia (<100,000 platelets/µL) at admission, inotrope requirement, and SARS-CoV-2 infection, but not the presence of IPA. This series shows that the isolation of Aspergillus spp. in respiratory samples, whether associated with disease criteria or not, is associated with high mortality, especially in patients with SARS-CoV-2 infection, and suggests an early initiation of treatment given its high mortality rate.