Piperacillin-tazobactam and Temocillin as Carbapenem-alternatives for the Treatment of Severe Infections Due to Extended-spectrum Beta-lactamase-Producing Gram-negative Enterobacteriaceae in the Intensive Care Unit

Inclusion Criteria: * Patients ≥ 18-year-old * Hospitalized in the ICU * Severe infection, eg sepsis or septic shock (according to the Sepsis-3 definition) Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, characterized by an increase of Sequential Organ Failure Assessment (SOFA) score of 2 points or more. This increase in 2 points will be calculated the day infection is diagnosed (day of positive culture serving as reference for the infection) as compared to the day before infection onset. Septic shock is defined as sepsis and persisting hypotension requiring vasopressors to maintain mean arterial pressure ≥65 mmHg and having a serum lactate level \>2 mmol/l despite adequate volume resuscitation. This criterion (sepsis or septic shock) has to be fulfilled within a time frame of +/- 24 hours from the day of infection diagnosis (i.e. the day of positive bacteriological sample). * Pathogen responsible for infection is an ESBL-producing Enterobacteriaceae susceptible to meropenem and either to piperacillin/tazobactam (minimum inhibitory concentration \<8 mg/L) or to temocillin (minimum inhibitory concentration ≤8 mg/L) * Signed Informed consent from patient/a legal representative/a family member/a close relative. According to the specifications of emergency inclusion, randomization without the close relative or surrogate consent could be performed if the patient is unable to give his/her consent and when the legal representative/family member or close relative are absent except patients included in another study for which emergency inclusion has already been used (see exclusion criteria n° 8). For these patients, emergency inclusion cannot be used). Close relative/surrogate/family consent will be asked as soon as possible. The patient will be asked to give his/her consent for the continuation of the trial when his/her condition will allow * Affiliation to social security (AME excluded) Exclusion Criteria: * Pregnancy or breastfeeding * Known allergy to beta-lactam * Patient with severe neutropenia, as defined by absolute neutrophil count \<0.5x109/L * Infection requiring prolonged antimicrobial treatment (endocarditis; mediastinitis; osteomyelitis/septic arthritis; undrainable/undrained abscess; unremovable/unremoved prosthetic-associated infection) * Moribund, defined by a SAPS II score at inclusion \>75 * Decision of withholding/withdrawing care * Patient with concomitant infection requiring antibiotics with activity against Gram-negative bacilli, including patient with polymicrobial infection with pathogen resistant to study drugs * Participation in another interventional study evaluating drugs or being in the exclusion period at the end of a previous study evaluating drugs . * Hypersensitivity to any components of the formulations