Multiyear experience with blood culture results from a tertiary care hospital in Saudi Arabia: a retrospective study.

BACKGROUND: Bloodstream infections (BSI) are a significant etiology of morbidity and mortality in hospitalized patients, particularly among critically ill patients in intensive care units (ICU). ICU patients are at a higher risk of BSI due to invasive procedures, prolonged hospitalization, and the prevalence of multidrug-resistant organisms (MDROs). Blood culture remains the gold standard for diagnosing BSI and its associated resistance pattern. However, contamination during sample collection often limits its utility, and diagnostic accuracy leading to unnecessary antibiotic use, prolonged stay in the ICU, and increased healthcare costs. Understanding trends in blood culture contamination rates and factors associated with BSI in ICU patients is vital for optimizing infection control measures and antimicrobial stewardship programs. This study aims to analyze blood culture contamination rates and explore ICU-associated factors influencing BSI at a tertiary hospital. METHODS: This three-year retrospective study (2018,2022,2023) analyzed 27,544 blood culture samples from a tertiary hospital. Data were retrieved from the medical record system and included bacterial identification and antimicrobial susceptibility patterns. The contaminated blood culture rates over years were calculated and factors associated with BSI among ICU patients in 2022 and 2023 were analyzed using the Chi-square test. RESULTS: The study revealed a decrease in the contamination rate between 2018, 2022, and 2023 with a result of 6.3%, 3.7%, and 4.2%, respectively. Patients' age and hospital wards are the variables associated with the contaminated blood culture. Factors associated with positive blood culture for the ICU admissions in 2022 and 2023, included patient age, results of Gram stain, identified bacteria, resistance pattern, and length of stay. Gram-negative bacteria predominated in positive blood culture with Klebsiella spp. being the most frequently isolated organism across all the studied years. ESBL-producing bacteria remained the most common resistance pattern throughout the study period. CONCLUSIONS: This study reports a reduction in blood culture contamination rates during the studied years, suggesting improvement in clinical practices related to sample collection and microbiological techniques. However, the persistent predominance of ESBL-producing bacteria and Klebsiella spp. indicates the urgent need for further enhanced antimicrobial stewardship programs to combat antimicrobial resistance. Further national studies should focus on hospital-wide interventions to reduce contamination and improve patient outcomes.