Urine Culture Performance at a Tertiary Hospital in Dar es Salaam, Tanzania: A Call for Diagnostic Stewardship to Improve Urinary Tract Infection Management

Abstract

Background: Urinary tract infections (UTIs) are often caused by bacterial pathogens that affect the urinary system, including the kidneys, ureters, bladder, and urethra. They can spread to the bloodstream, leading to various clinical symptoms such as fever, flank pain, dysuria, cystitis, and pyelonephritis. Urinary tract infection can impact both males and females, as well as individuals of all ages. However, some urine samples that are accepted and cultured yield non-significant growth results that greatly exceed those of significant growth. We analysed the frequency distribution of urine culture outcomes and their relation to patient characteristics at a tertiary hospital.
Methodology: A retrospective, hospital-based, cross-sectional study was conducted at the Central Pathology Laboratory of Muhimbili National Hospital in Dar es Salaam, Tanzania, from July to August 2024, involving the review of archived urine culture data. Data of patients of all ages ranging from 6 months to 99 years old and both genders who were investigated for UTIs from January to December 2023 were included in the study. Data were collected using a structured data collection tool and analysed using the Statistical Package for the Social Sciences.
Results: Of 3,652 patients tested for UTI by urine culture, 2,189 (59.9%) were female, and 626 (17.1%) were under age 5. Only 828 (22. 7%) had significant bacterial growth detected, while 2217 (60.7%) showed no bacterial growth. Non-significant and mixed growth were observed in 322 (8.7%) and 285 (7.8%) of the participants, respectively. Female patients had higher rates of significant growth (24.4% vs. 20.0%) and non-significant growth (10.7% vs. 5.9%) (P<.001). Conversely, males had a higher frequency of negative cultures (66.8%) than females (56.6%) (P<.001). Patients aged 61 years or older exhibited the highest rate of significant growth (32.2%), with the lowest rate observed in adolescents (5–17 years) at 16.0%. This difference across age groups was statistically significant (P<.001). Non-significant growth was more common among outpatients (11.4%) than in ICUs (3.8%) and inpatients (8.5%) (P<.001).
Conclusion: This study demonstrates a low yield of urine cultures from among the clinically suspected UTI cases, as the majority of the cases were not confirmed microbiologically. It also describes significant differences in culture positivity across sex, age, and healthcare settings, underscoring the need for tailored laboratory and clinical practices.