title: Bacterial contamination and cleanliness of emergency department ultrasound probes.
abstract: OBJECTIVE
  As ultrasonography is increasingly used in the emergency department (ED), ultrasound equipment has become a potential threat to infection control. Improperly cleaned ultrasound probes may serve as a vector for pathogens such as methicillin-resistant Staphylococcus aureus (MRSA). The primary objective of this study was to determine the prevalence of MRSA colonization on ultrasound probes used in a busy, urban ED. It was hypothesized that cultures of our ED ultrasound probes would yield a significant number of positive results for MRSA.
  
  
  METHODS
  In this observational study, 11 ED ultrasound probes were randomly sampled on 10 different occasions. Samples were taken using a RODAC plate method and were cultured for MRSA and methicillin-sensitive Staphylococcus aureus (MSSA). On half of the randomly assigned sampling occasions, a visual inspection of each ultrasound probe for general cleanliness was conducted and recorded. Data were stratified by ultrasound location in the ED and analyzed using the Fisher exact test, with p < 0.05 deemed to be statistically significant.
  
  
  RESULTS
  Of 110 samples, no isolates of MRSA were cultured. One probe yielded a positive culture for MSSA. Probes in the medicine, trauma, and pediatrics areas were found to be clean 65%, 33%, and 70% of the time, respectively. This variability in probe cleanliness by ED location was found to be statistically significant (p < 0.01).
  
  
  CONCLUSIONS
  Contrary to our hypothesis, MRSA contamination of ultrasound probes was not found. This finding suggests that the spread of MRSA by ED ultrasound machines in a high-volume urban ED is unlikely. Further research at different centres with larger sample sizes is required before these results can be generalized.
authors.affiliation: Department of Emergency Medicine, Queen’s University, Kingston, ON.
authors.forename: Geoffrey E
authors.initials: GE
authors.lastname: Sanz
authors.forename: Jonathan
authors.initials: J
authors.lastname: Theoret
authors.forename: Michael M
authors.initials: MM
authors.lastname: Liao
authors.forename: Catherine
authors.initials: C
authors.lastname: Erickson
authors.forename: John L
authors.initials: JL
authors.lastname: Kendall
mesh_terms: D003120:Colorado; D004636:Emergency Service, Hospital; D004866:Equipment Contamination; D006801:Humans; D017053:Infection Control; D055624:Methicillin-Resistant Staphylococcus aureus; D013203:Staphylococcal Infections / Q000517:prevention & control / Q000635:transmission*; D014463:Ultrasonography / Q000295:instrumentation*