Contamination Risk Following
Low Level Disinfection
There are several studies that show Low Level Disinfection wipes are not as effective as High Level Disinfection methods.1-8
A recent study in a clinical setting confirmed that the LLD procedure alone is unsafe compared to using a HLD method such as UV-C that can reliably inactivate pathogens (HPV). The study stated that automated HLD method is strongly recommended to ensure patient safety. 2,6
Risk of infection following semi-invasive ultrasound procedures in Scotland, 2010 to 2016. The study highlighted LLD to be insufficient, as demonstrated by the results of a retrospective cohort study using linked national datasets from Scotland. The study revealed an increased infection risk in the 30 days following transoesophageal echocardiography, endocavitary and transrectal ultrasound.3
For transoesophageal echocardiography (TOE) scans, patients were 4.92 times more likely to have a positive bacterial cultures (HR = 4.92). The TOE inpatient prescribing antibiotics were not available as a national dataset.3
Various global guidelines recommend High Level disinfection, preferred over LLD for probes classified as semi-critical and critical probes.
Low Level Disinfection Ineffective in Killing High Risk Cancer Human Papillomavirus
Risk of infection following semi-invasive ultrasound procedures in Scotland, cohort study: 2010 to 2016.3
Contamination Remains After Low Level Disinfection Wipes
A meta-analysis found procedures using LLD wipes, contamination remained up to 12.9% for pathogenic bacteria and 1% for pathogenic viruses on endocavitary probes. Stating the probability of infection transmission of viral pathogens to patients from these procedures was estimated to be 1-6%.4
High Risk of infection following Low Level Disinfection. In a study conducted at the Gynecology Department of the Lyon University Hospital from July to October, 216 samples were collected before the ultrasound examination, after Low Level Disinfection applied. The results showed:
- 3.5%(7/198) transvaginal probes are detected to be contaminated with HR-HPV post examination
- 2.8%(6/216) transvaginal probes are detected to be contaminated with HR-HPV pre-examination
The study concluded that in all hospitals, where LLD is performed, the endovaginal ultrasound procedure must therefore be considered a source for nosocomial High Risk HPV infections. Recommending stringent use of high-level disinfectants.8
Transvaginal Ultrasound Probe Contamination Despite Probe Cover and Low Level Disinfection Wipes Used
There have been numerous cases of cross infection risks to patients due to manual ultrasound probe reprocessing:
- Patient contacting hepatitis C virus after transrectal prostate biopsy as part of an individual screening for prostate cancer.
- Patient contracting hepatitis B linked to improper ultrasound transducer disinfection that led to a fatality.3-7
- Clinical Guidelines COVID-19 in Australasian Emergency https://ace.mn/aac81
- Bloc S1, Mercadal L, Garnier T, Komly B, Leclerc P, Morel B, Ecoffey C, Dhonneur G. (2011) Evaluation of a new disinfection method for ultrasound probes used for regional anesthesia: ultraviolet C light. J Ultrasound Med. 2011 Jun;30(6):785-8. https://www.ncbi.nlm.nih.gov/pubmed/21632992
- Health Protection Scotland (HPS), NHS National Services Scotland (2017). NHS Scotland Risk Based Recommendations for the Decontamination of SemiInvasive Ultrasound Probes: Risk of infection following semi-invasive ultrasound procedures in Scotland, 2010 to 2016. Version 1.0.
- Leroy S. Infectious risk of endovaginal and transrectal ultrasonography: systematic review and meta-analysis. The Journal of hospital infection. 2013;83(2):99-106. NAN0046.
- Ferhi K, Roupret M, Mozer P, Ploussard G, Haertig A, de La Taille A. Hepatitis C transmission after prostate biopsy. Case Rep Urol. 2013;2013:797248.
- Maxime Pichon, Karine Lebail-Carval, Geneviève Billaud, Bruno Lina, Pascal Gaucherand and Yahia Mekki (2019) Decontamination of Intravaginal Probes Infected by Human Papillomavirus (HPV) Using UV-C Decontamination System. J. Clin. Med, 8, 1776; doi:10.3390/jcm8111776.
- Leroy, S., et al. (2014). “Impact of vaginal-rectal ultrasound examinations with covered and low-level disinfected transducers on infectious transmissions in France.” Infect Control Hosp Epidemiol 35(12): 1497-1504.
- Casalegno and et al. High Risk HPV Contamination of Endocavity Vaginal Ultrasound Probes: An Underestimated Route of Nosocomial Infection? PLOS ONE | 2012
- Medicines and Healthcare products Regulatory Agency (UK), Medical Device Alert Ref: MDA/2012/037.