A Study to Learn About the Study Medicine Aztreonam-Avibactam (ATM-AVI) in Infants and Newborns Admitted in Hospitals With Bacterial Infection (CHERISH)

Inclusion criteria

• ✓. Hospitalized with age from birth \<9 months, including preterm birth
• ✓. Part A: Receiving IV antibiotics for treatment of suspected or confirmed bacterial infection, including but not limited to cIAI, cUTI, HAP/VAP, BSI, or sepsis.
• ✓. Part B: Suspected or confirmed gram-negative bacterial infection requiring IV antibiotics, including but not limited to cIAI, cUTI, HAP/VAP, BSI, or sepsis.
• ✓. Received any other investigational medicinal product within the longer of 30 days or 5 half-lives before enrollment.
• ✓. Any medical or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
• ✓. Severe renal impairment or known significant renal disease, as evidenced by elevated serum creatinine at screening, or urinary output \<0.5 mL/kg/h for 6 consecutive hours or requirement for dialysis.
• ✓. Part B Only: Received \>24 hours of systemic antibiotic treatment for gram-negative organisms at time of enrollment, unless documented treatment failure or lack of improvement in at least one objective sign or symptom of infection after ≥48 hours of antibiotics.