Factors Associated With Blood Culture Contamination in Rural Hospitals in Japan: A Cross-Sectional Study

Background Blood culture, a cornerstone diagnostic test, is paramount for identifying bacteremia due to serious infections. However, its accuracy is jeopardized by contamination, often due to inappropriate collection procedures. Resource constraints and a limitation in specialized staff can heighten contamination risks in rural hospitals, underscoring the need to understand the associated demographics and conditions. This study aimed to elucidate the demographics and conditions associated with heightened blood culture contamination risk in rural hospitals to optimize testing practices and improve patient care. Methods A single-center, cross-sectional study was conducted in Unnan City Hospital, Unnan, Japan with participants suspected of having bacteremia. Data from the electronic medical records of 455 patients were analyzed using multivariate logistic regression with contamination as the dependent variable. Results Of the 455 patients who underwent blood culture testing, 321 and 134 tests were negative and positive for contamination, respectively. Older age and blood obtained from arteries were associated with a reduced risk of contamination (odds ratio (OR)=0.97; p=0.012, and OR=0.17; p=0.00069, respectively). Patients with dependencies exhibited an increase in contamination risk (OR=1.81; p=0.044). Patients admitted for infection demonstrated a reduced likelihood of sample contamination (OR=0.44; p=0.0034). The predominant organisms identified varied, with Escherichia coli being more frequent in uncontaminated blood samples and Staphylococcus epidermidis in the contaminated samples. Conclusion This study reveals a complex relationship between patient demographics, clinical practices, and the risk of contamination. Factors such as age, dependency status, and reason for admission were associated with sample contamination. Enhanced procedural stringency, microbial surveillance, and continuous training could mitigate these risks, particularly in resource-constrained settings. Identifying and understanding the factors influencing blood culture contamination can significantly bolster clinical practice in rural settings. While this study provides foundational insights, future research can deepen our understanding, ensuring the refinement of patient care protocols in similar environments.