Prevalence of Urine Culture Contamination in a Primary Care Outpatient Setting in Muscat, Oman: A retrospective cross-sectional study.

Abstract

Objectives: This study aimed to investigate the prevalence of urine culture contamination, determine related factors and identify the most prevalent uropathogens among samples collected from outpatients attending a primary healthcare setting in Muscat, Oman.

Methods: This retrospective, cross-sectional study was conducted from June 2022 to July 2023 at the primary health clinic of Sultan Qaboos University Hospital, Muscat, Oman. All urine cultures requested by physicians for ambulatory outpatients who attended the clinic during the study period were included. Collected urine samples underwent microbiological analysis, with positive cultures defined as significant growth of ≥10⁵ colony forming unit (CFU)/mL. Samples exhibiting 2 organisms growing at 10⁴ CFU/mL or 1 organism at 10⁴ CFU/mL and another at <10⁴ CFU/mL were considered potentially contaminated, as were samples showing the isolation of 3 or more organisms.

Results: A total of 775 urine cultures were analysed. Of these, 72.8% demonstrated no growth, 10.7% exhibited significant growth and 16.5% showed mixed growth, which may indicate possible contamination. Significant correlations were identified between positive culture growth and the patient's gender, symptoms and pregnancy status (P < 0.05 each). Escherichia coli (56.6%) and Klebsiella pneumoniae (12.0%) were the most frequently identified bacteria in positive cultures. Antibiotics were prescribed for 17.8% of patients, primarily empirically (79.7%).

Conclusions: This study identified a significant rate of urine culture contamination among outpatients attending a primary care setting in Muscat. These findings underscore the importance of proper urine sample collection techniques and judicious antibiotic prescribing practices to optimise patient care, minimise unnecessary resource utilisation and reduce the likelihood of antimicrobial resistance.