Treatment of severe infections caused by ESBL or carbapenemases-producing Enterobacteriaceae.

Enterobacteriaceae are the most frequent pathogens in the Intensive Care Unit. Due to their safety and activity, β-Lactams (BL) and carbapenems represented the most common strategy adopted against these germs. The increasing exposure to these molecules led to the development of several types of antimicrobial resistance as the expression of extended-spectrum β-lactamases (ESBLs) and carbapenemases. Great molecular variability exists among these enzymes, with significant clinical impact. To limit morbidity and mortality, old antibiotics were tested and represent viable alternatives for specific types of infections, or once the spectrum of susceptibility of each germ has been determined. Alongside, new molecules have been specifically designed but enzyme molecular variability prevents the existence of one single antibiotic which fits for all. Therefore, a quicker identification of the molecular identity of each germ, together with the knowledge of the activity spectrum of each antibiotic is crucial to tailor the therapy and make it effective.