Microbiologic assessment of the transabdominal ultrasound transducer head

The objectives of this study were to determine (1) the rate of bacterial isolation from the abdomen of women having obstetric ultrasonography, (2) the rate of bacterial transmission to the transducer head, and (3) the eradication rate after routine wiping of the transducer head. A total of 191 obstetric patients participated in this study. At the start of each day, the transducer head and the coupling gel were cultured. Aerobic cultures were obtained from each patient's periumbilical and suprapubic areas before the transabdominal scan and from the transducer head before and after wiping off the gel with a dry cloth. Daily transducer head and gel cultures were negative. Of the abdominal skin cultures, 175 (92%) were positive; 35 (18%) were positive for serious organisms, and 140 (74%) were positive for organisms of low virulence. Sixty percent of the transducer head cultures from women with abdominal skin pathogens were positive before the gel was wiped off. None of the cultures from the transducer head were positive after removal of the gel. We conclude that many women carry potentially virulent pathogens on the abdominal skin and that transmission of these organisms to the transducer head commonly occurs. Physical removal of the gel from the transducer head effectively eradicates these microorganisms, minimizing patient-to-patient transmission.