The purpose of this study is to learn about the study medicine CTB-AVP for the treatment of severe urinary tract infections that require hospitalization.

This study is seeking for:

• adult male and female participants who are healthy and weigh more than 50 kg.
• participants who have normal blood pressure, normal kidney and liver function
• participants willing to stay away from caffeine and other medicines for the duration of the study.

Participants will be required to stay in the study clinic for two weeks. All participants in this study will receive study medicine CTB-AVP by mouth one time each day on four different days. Study medicine will be given in capsules or tablets, on an empty stomach or will be taken with a meal. The study will look at the experiences of people receiving the study medicine. This will help determine if the study medicine is safe and effective.

Inclusion Criteria:

1. Male and female participants aged 18 years or older at screening who are overtly healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, vital signs and standard 12-lead electrocardiogram (ECGs), and with eGFR ≥75 mL/min (estimated using the 2021 CKD-EPI equation).
2. Participants who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures.
3. Have a body-mass index (BMI) of 16 to 32 kg/m2; and a total body weight >50 kg (110 lb).
4. Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent document (ICD) and in this protocol.

Exclusion Criteria:

• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurological, or allergic disease; including any condition affecting oral absorption or known allergy to cephalosporin group of antibiotics
• Use of prescription or nonprescription drugs and dietary and herbal supplements within 7 days or 5 half-lives (whichever is longer) prior to the first dose of study intervention or current use of any prohibited concomitant medications.
• Screening supine Blood Pressure (BP) ≥140 mm Hg (systolic) or ≥90 mm Hg (diastolic) for participants <60 years; and ≥150/90 mm Hg for participants ≥60 years old, following at least 5 minutes of supine rest
• Participants with ANY of the following abnormalities in clinical laboratory tests at screening, as assessed by the study-specific laboratory and confirmed by a single repeat test, if deemed necessary: alanine aminotransferase (ALT), aspartate aminotransferase (AST), Bilirubin ≥1.5 x Upper Limit of Normal (ULN). Participants with a history of Gilbert's syndrome may have direct bilirubin measured and would be eligible for this study provided the direct bilirubin level is ≤ ULN.

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.