Urinary tract infections (UTI) affect the urine pH and may lead to salt precipitation such as struvite. Bacteria with urease activity are known to alkalinise urine, but not much is known on how pH is changing over time during UTI.

This study aims at following urine pH progression at the time of diagnosis of UTI and during the treatment phase.

Description of the change in urine pH over time will help understanding the risk of struvite formation and potential timing of intervention.

Adults presenting with UTI symptoms will be screened for infection and instructed to monitor urine pH during the course of treatment and 1 week after. Urine pH will be measured by the patients using calibrated pH-stix. Type of bacteria, antibiotics, and the type of diet will be monitored during the study.

Group 1. Cystitis

Inclusion Criteria:

• Symptoms of dysuria, pollakiuria, no fever AND
• urine-stix positive for leucocytes OR positive culture (>10E5 cfu/ml)

Group 2. Pyelonephritis

Inclusion Criteria:

• Unilateral flank pain, pollakiuria, dysuria, fever (>38.5°C) AND
• urine-stix positive for leucocytes OR positive culture (>10E5 cfu/ml)

Exclusion Criteria (both groups):

• known urinary tract anatomic abnormalities
• Presence of a urine catheter
• Sepsis - septic shock
• Patient taking drug interfering with urine pH (diuretics, citrate, acetazolamide, topiramate,...)
• Patients with UTI diagnosed in the preceding month
• Patients having received antibiotics during the preceding month
• Male patient with a diagnosis of prostatitis
• Presence of infected kidney cyst
• Patient with diabetes
• Pregnant female
• Patient with obstructive pyelonephritis

Patient consulting the primary care unit of the medical outpatient clinic UniSanté in Lausanne will be asked to participate.