Reducing Transmission Risk Through High-Level Disinfection of Transvaginal Ultrasound Transducer Handles

Abstract

Intracavity ultrasound transducer handles are not routinely immersed in liquid high-level disinfectants. We show that residual bacteria, including pathogens, persist on more than 80% of handles that are not disinfected, whereas use of an automated device reduces contamination to background levels. Clinical staff should consider the need for handle disinfection.Infect Control Hosp Epidemiol 2015;36(5): [581][582][583][584] Ultrasound transducers that contact broken skin or mucous membranes are considered semicritical devices and should undergo high-level disinfection (HLD) between patients. 1 Studies have shown residual contamination on ultrasound transducers when HLD is not performed 2,3 and cases of hepatitis B and C infection have been reported where transmission was thought to have been caused by improper reprocessing of ultrasound transducers. 4,5 HLD methods that involve soaking ultrasound transducers in liquid chemicals, such as glutaraldehyde or ortho-phthalaldehyde, do not typically disinfect the handle. Some major manufacturers specifically advise against submersion of the handle owing to the transducer not being fully sealed. There are no clear recommendations on whether transducer handles should be disinfected, nor is there any consensus on the risk that contaminated transducer handles might pose to patients.Although full immersion of transducers in liquid is not generally possible, approaches that allow the HLD of the entire transducer are now available. This study surveyed the residual contamination on transducer handles when not disinfected (routine soaking method) and also assessed the efficacy of an automated disinfection device capable of disinfecting both heads and handles of ultrasound transducers. methodsThis study was a prospective, bi-centric, cross-sectional study, performed at an ultrasound clinic and public hospital. No patients were excluded and no patient data were collected so the study did not require ethics approval. Following routine ultrasound procedures, all transducers were cleaned with detergent and water and were dried with paper towels. Handle samples were then collected from 2 study groups after the handles were subjected to different disinfection methods. Groups were sampled sequentially in randomized order.The first group of transducers (hereafter referred to as "glutaraldehyde disinfection of head only" [GDHO]) underwent reprocessing according to the existing protocol at the clinic where the head of the transducer was soaked in a 2.4% solution of glutaraldehyde for 20 minutes at room temperature. Transducer handles were not disinfected (per normal practice).The second group of transducers (hereafter referred to as "automated disinfection of head and handle" [ADHH]) were subjected to HLD with an automated disinfection system that disinfects the entire transducer including the handle (trophon EPR; Nanosonics). The device was operated according to the manufacturer's instructions for use.Matched control samples (shams) were collected to quantify contamination occurring during...

The importance of infection prevention and control in medical ultrasound

“…Causative agents of urinary tract infections were also isolated from the handle including Staphylococcus haemolyticus, Staphylococcus saprophyticus and Enterococcus faecium. Handle contamination decreased to background levels after disinfection with an automated system designed for simultaneous disinfection of the probe handle and body 16 . Others have reported similar figures (83% when the handle is not disinfected) 11 .…”

“…Some probe manufacturers contraindicate immersion of probe handles in liquid disinfectant (since the handle is not fully sealed) while other manufacturers state that this is possible, but that the cable should not be immersed. This often results in confusion and immersion protocols exclusively for the probe body without consideration for handle disinfection 15 , 16 . A recent study reported 80.5% of vaginal ultrasound device handles were contaminated with clinically relevant bacteria following probe body immersion in glutaraldehyde per normal practice; S. aureus was isolated in 15.4% of these samples and one isolate was found to be methicillin‐resistant Staphylococcus aureus (MRSA).…”

Virucidal efficacy of a sonicated hydrogen peroxide system (trophon ® EPR) following European and German test methods

“…Therefore, official authorities in many countries are requesting a high-level disinfection for transvaginal probes [8], [9], [10]. Data are available that automated devices can reduce contamination of intracavity ultrasound probes to background levels [5]. One study showed that the automated device could reduce contamination with a success rate of 91.4% while a manual wipe method showed greater contamination (success rate of 78.8%) based on a study measuring bacterial contamination rates [12].…”

“…Among HPV certain high risk types like HVP16 and HPV18 are associated with cervical neoplasia. Several studies have shown intracavity ultrasound probes are contaminated with HPV following low level disinfection, and the virus can also be found throughout the gynaecological environment [2], [3], [4], [5], [6]. In a study with native HPV16 virions, it was shown that glutaral (GTA) and ortho -phthalaldehyde (OPA) were unable to inactivate the virus while hypochlorite and a peracetic acid (PAA)-silver based disinfectant were effective [7].…”

DEGUM Recommendations on Infection Prevention in Ultrasound and Endoscopic Ultrasound

“…FA ZIT: Für die Desinfektion von starren Endosonografiesonden kommen unterschiedliche Verfahren zur Anwendung: Behandlung mit viruziden Wischtüchern [117,118], Wischtücher plus Schaumanwendung [105], Tauchdesinfektionsverfahren [117,119], ein vollautomatisches Desinfektionssystem mit Wasserstoffperoxid-Aerosol [107,109,120,121] oder Verfahren, bei denen eine UV-C-Bestrahlung eingesetzt wird [122,123]. Während bei der alleinigen Anwendung von Wischtüchern zwar die meisten Bakterien, aber nicht immer auch alle Viren und keine bakteriellen Sporen abgetötet werden, werden mit den anderen Verfahren alle Mikroorganismen, z. T. inkl.…”