The primary objective of the study is to demonstrate that in ICU infections treated empirically by carbapenems and documented with GNB on direct examination of a respiratory, urinary and/or blood sample(s), the early de-escalation guided by the results of the betaLACTA® test is not inferior to the reference strategy de-escalating on antibiotic susceptibility test (AST) results obtained 48-72h after sampling, in terms of mortality at D90 and infection recurrence in ICU.