• Accumulation ratio for [AUC(0-Tau)] (Area under the plasma concentration-time curve of study drug) [RAUC(0-Tau)] [ Time Frame: Day 1 through Day 7 ]
• Accumulation ratio for Cmax (maximum plasma concentration) (RCmax) [ Time Frame: Day 1 through Day 7 ]
• Area under the plasma concentration-time curve of study drug at steady state during the dosing interval [AUC(0-Tau,ss)] [ Time Frame: Day 1 through Day 7 ]
• Area under the plasma concentration-time curve of study drug during the dosing interval on Day 1 [AUC(0-Tau)] [ Time Frame: Day 1 ]
• Incidence of all treatment- emergent adverse events, by severity level [ Time Frame: Day 1 through Day 11 ]
• Maximum plasma concentration (Cmax) of study drug after the first dose [ Time Frame: Day 1 ]
• Maximum plasma concentration at steady state (Css,max) of study drug following multiple daily dosing [ Time Frame: Day 7 ]
• Minimum plasma concentration of study drug at steady state (Css,min) [ Time Frame: Day 7 ]
• Minimum plasma concentration of study drug at the end of the dosing interval on Day 1 (Cmin) [ Time Frame: Day 1 ]
• Renal Clearance (CLR) of study drug [ Time Frame: Day 1 through Day 7 ]
• Steady state concentration of study drug after continuous infusion (Css) [ Time Frame: Day 7 ]
• Systemic plasma clearance (CL) of study drug [ Time Frame: Day 1 through Day 7 ]
• Time to Cmax (maximum plasma concentration) (Tmax) of study drug after the first dose [ Time Frame: Day 1 ]
• Time to Css,max (maximum plasma concentration at steady state) (Tss,max) of study drug [ Time Frame: Day 7 ]
• Volume of distribution of study drug during terminal phase (VZ) [ Time Frame: Day 1 through Day 7 ]

• Incidence of all treatment- emergent adverse events, by severity level [ Time Frame: Day 1 through Day 11 ]
• Maximum plasma concentration (Cmax) of study drug after the first dose [ Time Frame: Day 1 ]
• Time to Cmax (maximum plasma concentration) (Tmax) of study drug after the first dose [ Time Frame: Day 1 ]
• Minimum plasma concentration of study drug at the end of the dosing interval on Day 1 (Cmin) [ Time Frame: Day 1 ]
• Area under the plasma concentration-time curve of study drug during the dosing interval on Day 1 [AUC(0-Tau)] [ Time Frame: Day 1 ]
• Maximum plasma concentration at steady state (Css,max) of study drug following multiple daily dosing [ Time Frame: Day 7 ]
• Time to Css,max (maximum plasma concentration at steady state) (Tss,max) of study drug [ Time Frame: Day 7 ]
• Minimum plasma concentration of study drug at steady state (Css,min) [ Time Frame: Day 7 ]
• Steady state concentration of study drug after continuous infusion (Css) [ Time Frame: Day 7 ]
• Area under the plasma concentration-time curve of study drug at steady state during the dosing interval [AUC(0-Tau,ss)] [ Time Frame: Day 1 through Day 7 ]
• Systemic plasma clearance (CL) of study drug [ Time Frame: Day 1 through Day 7 ]
• Renal Clearance (CLR) of study drug [ Time Frame: Day 1 through Day 7 ]
• Volume of distribution of study drug during terminal phase (VZ) [ Time Frame: Day 1 through Day 7 ]
• Accumulation ratio for Cmax (maximum plasma concentration) (RCmax) [ Time Frame: Day 1 through Day 7 ]
• Accumulation ratio for [AUC(0-Tau)] (Area under the plasma concentration-time curve of study drug) [RAUC(0-Tau)] [ Time Frame: Day 1 through Day 7 ]

• Drug: AZACTAM
  A synthetic monobactam antibiotic originally isolated from Chromobacterium violaceum
• Drug: Ceftazidime-Avibactam
  An antibacterial combination product containing ceftazidime and avibactam

• Experimental: Arm 1
  2.5g dose of ceftazidime-avibactam (AVYCAZ) administered intravenously as a 2-hour infusion, every 8 hours for 7 days. N=8
  Intervention: Drug: Ceftazidime-Avibactam
• Experimental: Arm 2
  2.5g dose of AVYCAZ administered intravenously as a 2-hour infusion once, then 0.32g dose per hour daily as a continuous infusion (7.5 g/day) for 7 days. N=8
  Intervention: Drug: Ceftazidime-Avibactam
• Experimental: Arm 3
  2g dose of aztreonam (ATM) administered intravenously as a 2-hour infusion, every 6 hours for 7 days. N=8
  Intervention: Drug: AZACTAM
• Experimental: Arm 4
  2g of ATM administered intravenously as a 2-hour infusion once, then 0.33g dose administered intravenously per hour, daily as a continuous infusion (8 g/day) for 7 days. N=8
  Intervention: Drug: AZACTAM
• Experimental: Arm 5
  2.5g dose of AVYCAZ administered intravenously as a 2-hour infusion, every 8 hours for 7 days, and a 1.5g dose of ATM administered intravenously as a 2-hour infusion, every 6 hours for 7 days. N=8
  Interventions:

  • Drug: AZACTAM
  • Drug: Ceftazidime-Avibactam
• Experimental: Arm 6
  2.5 g dose of AVYCAZ administered intravenously as a 2-hour infusion every 8 hours for 7 days, and a 2g dose of ATM as a 2-hour infusion every 6 hours for 7 days. N=8
  Interventions:

  • Drug: AZACTAM
  • Drug: Ceftazidime-Avibactam

Inclusion Criteria:

1. Provide a signed and dated written informed consent.
2. Be able to understand and willing to comply with study procedures, restrictions, and requirements, as determined by the Principal Investigator (PI).
3. Male and female volunteers aged 18 to 45 years inclusive.
4. Suitable veins for cannulation or repeated venipuncture.

5. Subject must be in good general health as judged by the investigator as determined by medical history, vital signs*, body mass index (BMI) and body weight**, clinical laboratory values***, and physical examination (PE).

   *Oral temp <38.0 degrees Celsius/100.4 degrees Fahrenheit; pulse 50 to 100 bpm; systolic blood pressure 90 to 140 mm Hg, and diastolic blood pressure 55 to 90 mmHg.

   **BMI between 19-33 kg/m^2 and body weight > / = 50 kg

   ***Clinical chemistry, hematology, coagulation and urinalysis results within the clinical laboratory reference ranges; clinical laboratory values outside these ranges, if considered by the site investigator to be clinically insignificant, are also acceptable

6. Sexually active female subjects must be of non-childbearing potential**** or must use a highly effective method of birth control*****.

   ****Non-childbearing potential is defined as being post-menopausal for at least 18 months or surgically sterile via hysterectomy, bilateral oophorectomy, or tubal sterilization.

   *****Sexually active female subjects of childbearing potential must avoid becoming pregnant by using one of the following acceptable methods of birth control for 30 days prior to study product dosing and must be maintained for 30 days after last dose of study product: Intrauterine contraceptive device; OR Approved hormonal contraceptives (such as birth control pills, skin patches, Implanon(R), Nexplanon(R), DepoProvera(R) or NuvaRing(R)); OR Birth control must be captured on the appropriate data collection form.

7. Sexually active male subjects must be vasectomized or agree to use barrier contraception (condom with spermicide) from first dose of study product until 30 days following the last dose of study product.
8. Nonsmokers defined as abstinence from cigarette smoking or use of nicotine-containing products for 6 months prior to enrollment into the study.

Exclusion Criteria:

1. History of any clinically significant (CS) disease or disorder, medical/surgical procedure, or trauma within 4 weeks prior to the first administration of study product(s)*.

   *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

2. History or presence of gastrointestinal, hepatic, or renal disease, or any other condition known to interfere with absorption, distribution, metabolism, or excretion of drugs.
3. Known history of a clinically important allergy/hypersensitivity to AVI, any monobactam, any beta-lactam and/or L-arginine.
4. Receipt of probenecid or furosemide within 14 days prior to study enrollment.
5. Receipt of any antibiotics within 14 days prior to study enrollment.
6. Receipt of prescription medications (except birth control pills or hormone replacement in females) within 14 days prior to study enrollment, unless in the opinion of site investigator the medication will not interfere with the study procedures or impact subject safety.

7. Receipt of non-antibiotic medications that interacts with OAT3** within 14 days prior to study enrollment.

   **Adefovir, Anagliptin, Baricitinib, Cefaclor, Cimetidine, Ciprofloxacin (Systemic), Clofarabine, Eluxadoline, Empagliflozin, Furosemide, Ketoprofen, Methotrexate, Mycophenolate, PEMEtrexed, Penicillin G (Parenteral/Aqueous), Penicillin G Benzathine, Penicillin G Procaine, Penicillin V Benzathine, Penicillin V Potassium, Zidovudine

8. Receipt of herbal and dietary supplements (including St. John's Wort) within 14 days prior to study enrollment.
9. ALT or AST laboratory value above the ULN as defined in the toxicity table.

10. Prolonged QTcF (> 450 msec) or shortened QTcF (< 340 msec) or family history of long QT syndrome. Any clinically important abnormalities in rhythm, conduction, or morphology of resting ECG***.

    ***Abnormalities that may interfere with interpretation of QTc interval changes per the medical judgment of the PI.

11. Any positive result on screening for human immunodeficiency virus (HIV) serum hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) antibody.
12. Creatinine clearance equal or less than 80 mL/minute (measured by Cockcroft-Gault method).
13. History of Clostridium difficile infection in past 90 days.
14. Known or suspected history of drug or alcohol abuse within the last 5 years, as judged by the PI.
15. Positive screen for drugs of abuse, cotinine (nicotine), or alcohol at screening and at admission to the study site prior to the first administration of the study products(s).

16. Received a new chemical entity (compound not approved for marketing) or participated in a study that included drug treatment within 1 month of the first dose of study product(s) for study ****.

    ****Period of exclusion begins at the time of the last visit of the prior study.

    Note: subjects consented and screened, but not dosed in this study or a previous Phase I study will not be excluded.

17. Previous participation in the present study.
18. Involvement in the planning and/or conduct of the study.

19. Any ongoing/recent (during screening) medical complaints that may interfere with analysis of study data or are considered unlikely to comply with study procedures, restrictions, and requirements *****.

    *****Judgment by the PI that the subject should not participate in the study.

20. Known history of past or current epilepsy or seizure disorders, excluding febrile seizures of childhood.