Bacterial contamination of ultrasound probes in emergency departments: A multicentre observational study.

Background: Ultrasound is frequently used in emergency departments (ED) for patient evaluation and diagnosis. Despite the risk of probe contamination from body fluids and blood, the rate of such contamination remains unclear.

Aim: This study aimed to evaluate bacterial contamination of ultrasound probes in EDs, focusing on hospital types and reprocessing methods.

Methods: A multicentre prospective observational study was conducted at a university hospital, a non-academic tertiary hospital, and a regional hospital in 2023. Samples were collected from probes used on ED patients. Reprocessing methods included water-moistened wipes alone, water-moistened wipes with ethanol wipes, quaternary ammonium wipes alone, and quaternary ammonium wipes with ethanol or hypochlorite wipes. Outcomes included the level of bacterial contamination, measured by colony-forming units (CFU) per total surface area of each probe, and resistant bacterial strains.

Findings: The median CFU was 10 (IQR: 0-50) at the university hospital, 40 (10-135) at the non-academic tertiary hospital, and 30 (1-95) at the regional hospital. By reprocessing method, the median CFU was 20 (1-90) for water-moistened wipes alone, 10 (0-20) for water-moistened wipes and additional ethanol wipe, 90 (40-180) for quaternary ammonium wipes alone, and 20 (1-50) for quaternary ammonium wipe and additional ethanol or hypochlorite wipe. Resistant bacterial strains were found on 18.2% of probes.

Conclusion: High levels of bacterial contamination, including resistant strains, were observed on ultrasound probes in EDs, regardless of facility type and reprocessing method.

Clinical trial number: Not applicable.