A prospective observational study on the efficacy of procalcitonin as a diagnostic test to exclude lower urinary tract infection and to minimize antibiotic overuse.

Background: Urinary tract infection (UTI) stands out as the third-most common infection following gastrointestinal and respiratory tract infections. Over the past decade, the biomarker procalcitonin (PCT) has gained prominence to facilitate the detection of bacterial infections and reduce excessive antibiotic exposure. Objective: The objective of this study was to mitigate the overuse of antibiotics, by promoting the noninitiation or early discontinuation of empirical antibiotics, which would significantly help minimize the proliferation of multidrug-resistant bacteria. Methodology: A prospective observational study was carried out at the tertiary care center in the Department of General Medicine of Kalinga Institute of Medical Sciences, Bhubaneswar, involving 200 patients with symptoms of lower UTI such as increased frequency, urgency, burning micturition, retention, and suprapubic tenderness with or without positive urinalysis. Detailed demographic profiles along with symptoms at the time of admission were recorded in a pretested structured format. To determine a positive diagnosis of UTI, signs and symptoms of UTI with or without urinary cultures were tested. The PCT level was estimated using enhanced chemiluminescence technique. Other routine tests such as complete blood count, renal function test, liver function test, urine routine microscopy, culture, chest X-ray, and ultrasonography abdomen pelvis were done and recorded. All patients, who had an initial serum PCT level of < 0.5 ng/mL, were kept under observation with only conservative and symptomatic treatments. Patients were further reviewed for improvement in symptoms and repeat urine microscopy. All patients, who had an initial serum PCT level of > 0.5 ng/mL, were initiated with antibiotics as per the culture and sensitivity reports. Patients were followed up for improvement in symptoms with reports of repeated urinalysis. Results: Our study reported the fact that 9.5% of the patients with initial serum PCT ≥ 0.5 ng/mL showed no improvement in symptoms despite starting antibiotics while significantly higher number of symptomatic patients (60%) with initial serum PCT < 0.5 ng/ml showed improvement in symptoms with conservative treatment without antibiotics. Conclusion: A lower PCT level rules out bacterial invasion and thus can be used as a novel marker in antibiotic stewardship.