To Investigate the Safety and Tolerability of Aztreonam-Avibactam (ATM-AVI)

Inclusion Criteria: * Provision of signed and dated, written informed consent prior to any study specific procedures * Healthy young male and female volunteers aged 18 to 45 years (inclusive) and healthy elderly volunteers aged 65 or older (Part C) with suitable veins for cannulation or repeated venipuncture * Have a body mass index (BMI) between 19 and 30 kg/m2 * Be able to understand and willing to comply with study procedures, restrictions, and requirements, as judged by the PI Exclusion Criteria: * History of any clinically significant disease or disorder which, in the opinion of the PI, may either put the volunteer at risk because of participation in the study, or influence the results or the volunteer's ability to participate in the study * History or presence of gastrointestinal, hepatic, or renal disease, or any other condition known to interfere with absorption, distribution, metabolism, or excretion of drugs * Known history of severe allergy to betalactam and/or L-arginine * History of severe allergy/hypersensitivity or ongoing clinically important allergy/hypersensitivity, as judged by the PI or history of hypersensitivity to drugs with a similar chemical structure or class to ATM or AVI * Any clinically significant illness, medical/surgical procedure, or trauma within 4 weeks prior to the first administration of IP