Patient description: The patients is a 25-year-old G1 P1 pregnant woman who is 24W3D gestational old who developed a sudden unset of fever and chills, accompany with nausea and vomiting. She also complains of dysuria, urgency and frequency. She also reports some severe pain in the flank. Her vital signs are: T = 39.7ºC, P = 117, R = 20, and BP = 113/74 mm Hg. Physical examination reveals tenderness on palpation of both costovertebral angles. She has no history of recurrent UTI prior to her pregnancy or any other underlying disease. The urine culture showed Gram-negative rod-shaped bacterial cells, leukocytes, and leukocyte casts. The blood culture is negative. A CBC shows Hb 12.9 g/dL, Hct 39%, MCV 76 fL, WBC count 14,120/µL.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Urinary Tract Infection Complicated Acute Pyelonephritis Patients willing to provide informed consent and who are willing to or likely to comply with all study requirements 2. Patients of either gender must have age ≥ 18 years 3. Patients with suspected cUTI based on clinical signs and symptoms 4. Urine culture results confirm bacterial urinary tract infection caused by β-lactamase producing gram negative bacteria requiring intravenous therapy 5. Patients with indwelling catheters should have the catheter removed or replaced (if removal is not clinically acceptable) before or as soon as possible, but not longer than 12 hours, after randomization 6. Obstructive uropathy, where the obstruction is likely to be relieved by stent or nephrostomy tube no later than 24 hours after randomization 7. Patients having received antibiotics for complicated urinary tract infection only if the duration of therapy was ≤ 24 hours within 72 hr of enrollment 8. Patients having received prior antibiotics and not showing any clinically significant improvement irrespective of duration of therapy 9. Females of childbearing potential require a negative urine pregnancy test and must agree to abstinence or to use an effective method of contraception  Patients with clinically significant cardiovascular, renal, hepatic, gastrointestinal conditions, neurological, psychiatric, respiratory, other severely immunocompromised, haematological, or malignant disease and other condition which may interfere with the assessment. History of uncontrolled diabetes mellitus, HIV and hepatitis B were excluded. 2. Patients with history of resistance to any of the investigational drugs were excluded from the study 3. Patients with history of hypersensitivity or allergic response, any contra-indications to penicillin, cephalosporin groups of drugs 4. Patients with creatinine clearance below 30 mL/min 5. Patients having abnormal laboratory parameters which in the opinion of PI are clinically significant enough to pose any undue safety concern for the patient or can interfere with patient's assessment 6. Perinephritic abscess or renal corticomedullary abscess, polycystic kidney disease, only one functional kidney, chronic vesicoureteral reflux 7. Uncomplicated UTI 8. Previous or planned renal transplantation or cystectomy 9. Urinary tract surgery within 7 days prior to randomization or urinary tract surgery planned during the study period (except surgery to relieve obstruction, to place a stent or nephrostomy) 10. Patients with a Body Mass Index ≥ 35 kg/m^2 11. Pregnant or lactating women 12. Participation in any clinical study within the previous 6 months