A Study to Assess How Vaborem® is Taking up in the Body and Tolerated in Paediatric Patients With Gram Negative Infections, Including But Not Restricted to Complicated Urinary Tract Infections

• Meropenem plus vaborbactam (Drug): Meropenem plus vaborbactam fixed dose combination adjusted by body weight up to 2g/2g

Primary outcomes

• Area under the concentration-time curve (AUC) for Meropenem [Day 3]
• Area under the concentration-time curve (AUC) for Vaborbactam [Day 3]
• Maximum plasma concentration (Cmax) for Meropenem [Day 3]
• Maximum plasma concentration (Cmax) for Vaborbactam [Day 3]
• Clearance (CL) of Meropenem [Day 3]
• Clearance (CL) of Vaborbactam [Day 3]
• Half-life (t1/2) of Meropenem [Day 3]
• Half-life (t1/2) of Vaborbactam [Day 3]
• Steady-state volume of distribution (Vss) of Meropenem [Day 3]
• Steady-state volume of distribution (Vss) of Vaborbactam [Day 3]

Secondary outcomes

• Number of patients experiencing Treatment Emergent Adverse Events (TEAE) [From baseline (day 1) to the last follow up visit (up to day 30)]

Sex: All, ages: 0 Months to 17 Years

Main Inclusion Criteria:

* Written informed consent before initiation of any study-related procedures.
* Male or female, from birth to < 18 years of age, inclusive.
* Require hospitalization and a minimum of 3 days of IV antibiotic treatment for suspected or confirmed Gram negative infection as per Investigator's judgement.
* Gram negative infection, according to diagnostic criteria for complicated urinary tract infection/acute pyelonephritis (cUTI/AP), complicated intra-Abdominal Infections (cIAI), Hospital-Acquired Pneumonia/Ventilator Associated Pneumonia (HAP/VAP), Blood-Stream Infection (BSI).

Main Exclusion Criteria:

* History of any moderate or significant hypersensitivity or allergic reaction to beta-lactam antibiotics or to any component of the investigational medical product.
* Gram negative infection that in the opinion of the Investigator is unlikely to respond to the study treatment.
* In treatment with immunosuppressive agents, valproic acid, or probenecid.