This is a non-randomized, open-label, one-treatment, one group study in participants with complicated urinary tract infection (cUTI) including pyelonephritis to characterize the pharmacokinetics of RO7079901 co-administered with meropenem.

Inclusion Criteria:

• Requiring hospitalization for IV antibacterial therapy for the treatment of presumed/confirmed cUTI (including pyelonephritis)
• Clinical signs and/or symptoms of pyelonephritis or a cUTI
• Urine culture taken within the 48 hours (hr) period immediately preceding the first dose of study drug contains greater than (>)1x10^5 colony forming units (CFU) per milliliter (CFU/mL) of a gram negative organism
• Negative urine pregnancy test result confirmed by a blood test
• Agreement to remain abstinent or use a contraceptive method

Exclusion Criteria:

• Has a concomitant infection requiring antibacterial therapy, in addition to study drug
• Confirmed fungal urinary tract infection
• Moderate or severe renal impairment, or end-stage renal disease requiring renal replacement therapy or a recipient of a renal transplant
• Documented presence of immunodeficiency, or a severely immunocompromised condition or use of systemic immunosuppressant therapy
• Any rapidly progressing disease or immediately life-threatening illness, or other terminal illness or condition with high risk of mortality meaning that the participant is considered, in the opinion of the Investigator, unlikely to survive the study period
• Urinary tract surgery or clinically significant urogenital trauma in the one week immediately preceding study entry
• Urinary tract infection (UTI) symptoms potentially attributable to another process (sexually transmitted infections or prostatitis)
• Suspected or confirmed perinephric or intra renal abscess
• Complete obstruction of any portion of the urinary tract, or a permanent urinary diversion
• History of epilepsy, brain lesions or other significant neurological disorders
• Use of probenecid within the 7 days before enrollment
• Known history of clinically significant hypersensitivity or severe allergic reaction to meropenem or any other antibiotic
• Any other ongoing condition or disease, or clinically significant abnormalities in laboratory test results that the investigator considers would render the participant unsuitable for the study
• Women who are pregnant, planning to become pregnant, or lactating
• Participation in a clinical study of an investigational drug or device within one month prior to enrollment
• Prior enrollment in this study