Severe infections caused by carbapenem-resistant Enterobacterales (CRE) represent a challenge for the clinicians, considering the high mortality rate of these infections. Data regarding the prevalence of CRE, clonal analysis, resistant genes (resistome) and virulence genes (virulome) molecular analyses, and clinical outcomes of infected patients are scarce. Thus, creating a network to Standardize and implement microbiological sourveillance could be crucial to answer this challenge. Our group consisting of the, UOC of Infectious Diseases and UOC of Microbiology (Prof Sanguinetti), the Microbiology Unit of the University of Catania (Prof. Stefania Stefani), the local Infectious Disease Unit (Dr Carmelo Iacobello) the Microbiology Unit of the "Magna Graecia'' University (Prof. Giovanni Matera) and the UOC of Infectious and Tropical Diseases UMG Catanzaro Prof Enrico Maria Trecarichi, has already started a project with promising ad interim results on this topic.

Inclusion Criteria:

1. age ≥ 18 years;
2. isolation of CRE from a clinically relevant sample considered to be the site of infection: pneumonia, UTI, IAI, spondylodiscitis and BSI.
3. Patients who by clinical practice have received at least one dose of the following drugs from ceftazidime-avibactam, meropenem-vaborbactam, and cefiderocol.
4. Signature of Informed Consent

Exclusion Criteria:

1. Subjects under 18 years of age
2. absence of CRE infections

Hospitalized patients with confirmed CRE infections, defined as pathogens resistant to meropenem, ertapenem, and imipenem, assessed by EUCAST (European Committee on Antimicrobial Susceptibility Testing) and who have received at least one dose of the following drugs: ceftazidime-avibactam, meropenem-vaborbactam, and cefiderocol.