GRAM NEGATIVES STUDY

This is a prospective, observational, multicenter study whose main objective is to develop a predictive model of mortality in critically ill patients colonized by multidrug-resistant Gram-negative bacteria (MDR-GNB).

Secondary objectives include: determining the characteristics of patients colonized by MRGB who require admission or acquire colonization during their stay in an intensive care unit (ICU); studying the infectious complications they develop, their etiology, clinical impact, and prognosis.

During the first month of data collection, all patients admitted to the ICU will be included regardless of their carrier status. Non-colonized patients will act as a "control group" and will allow us to evaluate the differences between the 'colonized' and "non-colonized" populations in the future.

Patients with positive samples for extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, carbapenemases, Pseudomonas aeruginosa, and multidrug-resistant Acinetobacter baumannii will be included in the study.

Data will be collected on the infectious complications they develop (a maximum of two per patient): bacteremia, ventilator-associated pneumonia, urinary catheter-associated infection, sepsis with an abdominal focus, and skin and soft tissue infections. (Priority will be given to recording the first two due to their greater clinical impact on critically ill patients).

The severity, need for artificial support treatment, and etiology of each infection will be analyzed. Data from the antibiogram will be collected, with special interest in sensitivities to carbapenems and new antibiotics available (ceftazidime-avibactam, ceftolozane-tazobactam, meropenem-vaborbactam, imipenem-relebactam, and cefiderocol). The adequacy and timeliness of the prescribed antimicrobial treatment will be analyzed. Clinical cure of the episode, recurrence, and the emergence of resistance to new antibiotics will be evaluated.

From the second month onwards, only patients colonized by multidrug-resistant Gram-negative bacteria upon admission, or those who acquire it during their stay in the ICU, will be included. A colonized patient will be considered to be one with at least one positive microbiological surveillance culture according to the RZ protocol, regardless of location. Colonization will be considered if any sample from the epidemiological study is positive upon admission to the ICU or if they acquire colonization during their stay. Colonization will be considered based on the results of the first study performed upon admission to the ICU or during the ICU stay, in cases where it is acquired during the stay in the unit. The main infectious complications that these patients develop, their etiology, and clinical impact will be recorded.