Cefiderocol AST in a real-life Klebsiella pneumoniae collection: challenges in the ATU range.

Objectives: FDC susceptibility testing is challenging as none of the commercial tests have been proven to accurately determine the susceptibility in the area of technical uncertainty (ATU). Here, we evaluated the performance of different FDC testing methods on Klebsiella pneumoniae isolates around this range.

Methods: A challenging collection of 104 K.

Circulating Polymorphonuclear Myeloid-Derived Suppressor Cells (PMN-MDSCs) Have a Biological Role in Patients with Primary Myelofibrosis.

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm characterized by a chronic inflammatory state that plays a relevant role in the disease pathogenesis (as proven by high levels of inflammatory cytokines with prognostic significance and by a persistent oxidative stress) and by extensive neoangiogenesis in bone marrow (BM) and spleen. Myeloid-derived suppressor cells (MDSCs) are immature cells that expand in patients with cancer, sepsis or chronic inflammation, favoring tumor onset and progression mainly through the decrease in immune surveillance and the promotion of neoangiogenesis. In this paper, we evaluated the presence of circulating MDSCs in PMF patients, the plasmatic factors involved in their mobilization/expansion and the correlations with laboratory, genetic and clinical parameters.

Automatic Discrimination of Species within the Enterobacter cloacae Complex Using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and Supervised Algorithms.

The Enterobacter cloacae complex (ECC) encompasses heterogeneous clusters of species that have been associated with nosocomial outbreaks. These species may have different acquired antimicrobial resistance and virulence mechanisms, and their identification is challenging. This study aims to develop predictive models based on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) profiles and machine learning for species-level identification.

Outbreak by KPC-62-producing ST307 Klebsiella pneumoniae isolates resistant to ceftazidime/avibactam and cefiderocol in a university hospital in Madrid, Spain.

Objectives: Ceftazidime/avibactam and cefiderocol are two of the latest antibiotics with activity against a wide variety of Gram-negatives, including carbapenem-resistant Enterobacterales. We sought to describe the phenotypic and genotypic characteristics of ceftazidime/avibactam- and cefiderocol-resistant KPC-Klebsiella pneumoniae (KPC-Kp) detected during an outbreak in 2020 in the medical ICU of our hospital.

Methods: We collected 11 KPC-Kp isolates (6 clinical; 5 surveillance samples) resistant to ceftazidime/avibactam and cefiderocol from four ICU patients (November 2020 to January 2021), without prior exposure to these agents.

Usefulness of EUCAST rapid antibiotic susceptibility breakpoints and screening cut-off values directly from blood cultures for the inference of β-lactam resistance mechanisms in Enterobacterales.

Background: Reducing the turnaround time for reporting antimicrobial susceptibility testing (AST) results is important for adjusting empirical treatments and may impact clinical outcomes of septic patients, particularly in settings with high antimicrobial resistance. Disc diffusion could be useful for inferring β-lactam resistance mechanisms.

Objectives: To evaluate the usefulness of EUCAST rapid AST (RAST) disc diffusion breakpoints for the screening of resistance mechanisms (sRAST) and interpretive reading of resistance phenotypes to infer ESBL and carbapenemases production in Enterobacterales.