A retrospective analysis of emergency department cultures in a tertiary care center

To describe the distribution and outcomes of cultures obtained in the emergency department (ED), examine contamination and microbiological yield across specimen types, and compare results between adult and pediatric settings.

We conducted a retrospective study including all cultures obtained over a 12-month period in the adult and pediatric EDs of a tertiary hospital. Demographic characteristics, culture type, microbiological results, and patient disposition were extracted from electronic records. Culture results were categorized as no growth, contamination/commensal-flora, bacterial growth with or without extended-spectrum β-lactamase (ESBL) production, yeast growth, or sample rejection.

A total of 2,674 cultures were analyzed. Nearly half of the cultures showed no growth (48.8%), and 24.3% were classified as contamination/commensal-flora based on laboratory report wording, representing low-interpretability flora reports rather than a formal blood culture contamination rate. Bacterial growth without ESBL production occurred in 16.6%, while ESBL-producing organisms were detected in 2.3%; yeast growth occurred in 1.0%, and 7.0% of samples were rejected. Urine cultures constituted the largest proportion and demonstrated higher rates of both growth and contamination/commensal-flora compared with blood and sterile body fluid cultures. Contamination/commensal-flora was more frequent in pediatric ED cultures, whereas hospitalized-particularly intensive care-patients had higher microbiological positivity and a greater prevalence of ESBL-producing organisms.

A substantial share of ED cultures yielded no growth or laboratory-wording-based contamination/commensal-flora reports, suggesting limited diagnostic interpretability in many cases. Variation by specimen type and patient disposition highlights the importance of selective culture ordering, improved collection practices, and integration of antimicrobial stewardship principles into ED workflows. Prospective multicenter studies incorporating clinical outcomes are needed to clarify the impact of ED culture practices on patient care.