Decontamination of transvaginal ultrasound probes: review of national practice and need for national guidelines

The use of ultraviolet light generated from light-emitting diodes for the disinfection of transvaginal ultrasound probes

Transvaginal ultrasound probes (TVUS) are used for several gynecological procedures. These need to be disinfected between patient use. In the current study we examine whether UVC delivered using light emitting diodes for 90 seconds can provide sufficient disinfection efficacy. A new UVC device that delivers UVC radiation at 265nm-275nm for 90 seconds was used. TVUS probes were swabbed before and after use in an in vitro fertilization clinic. Microbes on the swabs were cultured and identified. In addition, the ability of the UVC device to provided repeated high-level disinfection was analysed by deliberately contaminating probes with spores of Bacillus subtilis and then performing the UVC disinfection and bacterial culture. 50% of probes were contaminated with bacteria, most commonly Bacillus sp., directly after in vivo use. Whereas 97% were sterile after UVC disinfection for 90 seconds. The UVC treatment resulted in no growth of B. subtilis spores after each of five repeated contaminations with 5-9 x 107 spores on the probes. This study has found that UVC delivered via light emitting diodes for only 90 seconds can produce high level disinfection of transvaginal probes.

Endocavity Ultrasound Transducers: Why High-Level Disinfection Is Necessary

As a medical imaging modality, ultrasound is used by a wide cross-section of practitioners including radiologists, obstetricians, gynecologists, gastroenterologists, urologists and cardiologists. The increasing popularity of ultrasound as a diagnostic tool is due not only to the ease of use and portability of systems, but also to the perceived safety aspect of the examination. This latter point needs to be examined. As with any reusable medical device, the ultrasound transducer, also known as a probe, could potentially be a vector for the transmission of pathogenic viruses and fungi between patients if not correctly disinfected after each use. This transmission risk is magnified for an endocavity transducer that has come in contact with the vagina, anal canal or oral cavity, as it could be contaminated with organisms transmitted by blood or mucosal, genital or rectal secretions. Based on the Spaulding system, transducers that come in contact with mucous membranes are classified as semi-critical devices that require high-level disinfection (HLD) after each patient procedure. This HLD process should eliminate all microorganisms except high numbers of bacterial endospores. Only a small number of countries worldwide have implemented transducer reprocessing guidelines that adhere to the Spaulding classification and recommend HLD for endocavity transducers. Overall, there is a lack of conformity among global health agencies regarding the use of HLD for endocavity transducers. This is primarily due to the perception that the infection transmission risk is negligible and that if an endocavity transducer has been covered with a single-use sheath for the procedure, then low-level disinfection provides sufficient protection against pathogen transmission. The objective of this study was to review the published risk of infection transmission from endocavity transducers. By highlighting the outbreaks and case reports that implicate pathogen transmission from transducers, we posit that HLD should be a global standard of practice for the reprocessing of endocavity transducers. It requires substantial time for national health administrations to develop and legislate new recommendations, and for practice changes to be accepted and implemented by healthcare providers. We recommend that Joint Commission International (JCI) and other equivalent organizations enforce the use of HLD of endocavity ultrasound transducers during their accreditation reviews.

Health Care-Associated Infections and the Radiology Department

Health care-associated infections (HCAIs) are a significant concern for both health care workers (HCWs) and patients. They are a major contributing factor of disease in industrialized countries, and are responsible for significant morbidity, mortality, and a direct annual financial loss of $6-7 billion in North America alone. They are an increasingly challenging health issue due to multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci among others, along with an increasing number of susceptible patients. Over the last three decades, the risk of HCAIs has increased in the radiology department (RD) in part because of an increased number of patients visiting the department and an increase in the utilization of imaging modalities. In this review, we will discuss how patients and staff can be exposed to HCAIs in the RD, including contaminated inanimate surfaces, radiology equipment, and associated medical devices. As the role of medical imaging has extended from primarily diagnosis to include more interventions, the implementation and development of standardized infection minimization protocols and infection control procedures are vital in the RD, particularly in interventional radiology. With globalisation and the rapid movement of people regionally, nationally, and globally, there is greater risk of exposure to contagious diseases such as Ebola, especially if infected patients are undiagnosed when they travel. For effective infection control, advanced training and education of HCWs in the RD is essential. The purpose of this article is to provide an overview of HCAIs as related to activities of the RD. We will discuss the following major topics including the variety of HCAIs commonly encountered, the role of the RD in HCAIs, transmission of infections to patients and HCWs in the RD, standard infection prevention measures, and the management of susceptible/infected patients in the RD. We shall also examine the role of, and the preparedness of, HCWs, including RD technologists and interventional radiologists, who may be exposed to undiagnosed, yet infected patients. We shall conclude with a brief discussion of the role of further research related to HCAIs. Learning Objectives After the completion of this review article, the readers will • Understand the exposure and role of radiology department in health care-associated infections, • Know the causes/modes/transmission of infections in radiology department, • Be conscious of standard disinfection protocols, • Be aware of current and future strategies required for the effective control of health care-associated infection in the radiology department. This is a CME article and provides the equivalent of 2 hours of continuing education that may be applied to your professional development credit system. A 10-question multiple-choice quiz follows this reading. Please note that no formalized credit (category A) is available from CAMRT.

Transvaginal ultrasound probes are human papillomavirus-free following low-level disinfection: cross-sectional multicenter survey

OBJECTIVES

To assess the frequency of detection of high-risk human papillomavirus (hrHPV) on transvaginal ultrasound (TVS) probes and keyboards and evaluate operator compliance with national recommendations for prevention of cross-infection during TVS.

METHODS

This was a multicenter observational survey involving 46 public and private centers, in the Paris region of France, in which at least five consecutive TVS examinations were performed per day. We audited 676 TVS procedures. We recorded preventive hygiene actions undertaken by the operator at three stages: (1) during TVS; (2) during probe disinfection; and (3) during preparation of the probe for the next TVS. After probe disinfection, we collected one sample from the bare probe and one from the ultrasound keyboard; following probe preparation for the next examination, an additional sample was obtained from the covered probe. The samples were tested for presence of hrHPV DNA using the Cobas® 4800 System.

RESULTS

We did not detect hrHPV DNA in samples collected from uncovered or covered probes (0%; 95% CI, 0.00-0.55%). Keyboard samples were positive for hrHPV in two cases (0.3%; 95% CI, 0.04-1.07%). During TVS, the operator avoided touching the keyboard with a hand that had touched the patient's vulva in 86% of cases and held the probe with a gloved hand in 68%. Before probe disinfection, the operator wore new gloves, or performed hand disinfection in 8% of cases. The probe disinfection technique used was adequate in 87% of cases, not performed at all in 12% and insufficient in 1%. Before preparing the probe for the next scan, the operators disinfected their hands or used new gloves in 81% of cases. The probe cover and the coupling gel used complied with recommendations in 98% and 46% of cases, respectively. Of the seven preventive hygiene actions recommended in national guidelines, all were performed in 2%, three to six in 95% and two in 3% of observations. In four (9%) centers, disinfection was not performed in over half the observations.

CONCLUSIONS

No evidence of hrHPV DNA was found on TVS probes and probe covers following low-level disinfection, despite suboptimal compliance with hygiene guidelines. Routine TVS practice could be made easier and safer with a global approach to probe disinfection and hand hygiene. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Guidance for the decontamination of intracavity medical devices: the report of a working group of the Healthcare Infection Society

BACKGROUND

Intracavity medical devices (ICMDs) are used in a wide variety of healthcare settings. The approach to their decontamination and the resources available also differ widely. Their potential for infection transmission is considerable.

AIM

To produce a comprehensive risk assessment-based approach to the decontamination of ICMDs, accompanied by an adaptable audit tool.

KEY RECOMMENDATIONS

Guidelines for Cleaning Transvaginal Ultrasound Transducers Between Patients

The purpose of this article is to provide guidance regarding the cleaning and disinfection of transvaginal ultrasound probes. These recommendations are also applicable to transrectal probes.

Advancing infection control in Australasian medical ultrasound practice

INTRODUCTION/AIMS

Australasia is witnessing a rapidly increasing use of diagnostic medical ultrasound in clinical practice with industry statistics giving a conservative estimate of ten million scans performed annually in Australia and New Zealand. Ultrasound practice has broadened from its traditional use in radiology, obstetrics and gynaecology, vascular and cardiology specialties to embrace emergency medicine, rheumatology, midwifery, physiotherapy, paramedics and other point of care practice. With this expansion of practice comes an increase in the potential risk for ultrasound transmitted bacterial or viral infection due to suboptimal cleaning habits of transducers, cords and keyboards.

RESULTS/CONCLUSION

This study describes results of an Australasian survey on the disinfection and hygiene practice in medical ultrasound. Results highlighted a significant need for updated guidelines and education on infection prevention and control in medical ultrasound.

The ultrasound unit and infection control - Are we on the right track?

Best practice guidelines for the disinfection of ultrasound transducers and infection prevention in ultrasound departments are generally recommended by either government health groups or the ultrasound societies of individual countries. The literature shows a wide variance in not only transducer cleaning methods but basic hygiene practices in the ultrasound workplace. This paper describes results from a UK survey of disinfection of ultrasound transducers and hygiene practice in the workplace. The survey revealed that some ultrasound practitioners did not follow current guidelines with regard to the correct disinfection method of transducers, cords or ultrasound machine keyboards. Furthermore, the survey exposed the lack of training from the product manufacturers on how to use the disinfection product appropriately. These inconsistencies may be responsible for compliance issues and highlight the need for an awareness campaign and a unified approach to infection control by ultrasound practitioners.

Infection prevention and ultrasound probe decontamination practices in Europe: a survey of the European Society of Radiology

OBJECTIVES

Although ultrasound (US) is considered one of the safest imaging modalities, concerns have been raised regarding potential infection transmission risks through US procedures. A survey was undertaken by the European Society of Radiology (ESR) to establish infection prevention and control measures in US and to highlight the importance of good medical practice.

METHODS

An online survey was sent to all 22,000 full ESR members.

RESULTS

The response rate of completed surveys was 4.3 % (946 practitioners, 97 % of which were radiologists, mostly working in larger hospital settings). Among respondents, 29 %, 11 % and 6 % did not disinfect the US probe after every patient when performing standard surface US, endo-cavity US and interventional procedures, respectively. Eleven percent did not always use probe covers for endo-cavity US; for interventional procedures, the proportion was 23 %. A minority used sterile gel sachets in direct patient contact for endo-cavity scans (30 %), and 77.5 % used sterile gel for interventional procedures.

CONCLUSIONS

The survey results highlight a wide range of practices throughout Europe and the need to raise awareness amongst practitioners regarding the importance of infection prevention and control measures. The development of European recommendations encompassing all US examinations, together with education is a priority.

MAIN MESSAGES

• Transmission of infection through ultrasound procedures is possible. • There is a wide range of ultrasound probe decontamination practices in Europe. • Not all practitioners use probe covers for endo-cavity or interventional ultrasound. • Not all practitioners use sterile gel for internal and invasive procedures. • Currently there are no European recommendations encompassing all US examinations.

Transvaginal sonographic features of perineal masses in the female lower urogenital tract: a retrospective study of 71 patients

OBJECTIVES

To assess the transvaginal ultrasonographic features of perineal masses in the lower urogenital tract in a cohort of 71 women.

METHODS

Seventy-one women with perineal masses were referred consecutively for transvaginal ultrasonography. Two-dimensional (2D) ultrasound was used to scan the pelvic floor, including the urethra, vagina and rectum, and identify any possible areas of interest. A static three-dimensional (3D) sonographic reconstruction of the pelvic anatomy was created to further delineate the relation of the lesions with their neighboring structures. Ultrasound results were compared retrospectively with surgical pathology outcome when possible.

RESULTS

Seventy-nine cystic, cystic-solid or solid masses were detected on transvaginal 2D ultrasonography in the 71 women: in 44 patients, 47 anechoic cystic masses were identified and diagnosed as vaginal wall cysts; in 19 patients, 23 hyperechoic cystic masses were diagnosed as vaginal epidermoid cysts; in each of two patients, a hypoechoic cystic-solid mass showing blood-flow signals on color Doppler imaging was diagnosed as urogenital angiomyofibroblastoma; in each of three patients, a hypoechoic cyst was diagnosed as urethral diverticulum; and in three patients with a known history of gynecological malignancy, solid heterogeneous masses with blood flow signals on color Doppler imaging were diagnosed as metastatic cancer. In all patients, 3D ultrasonography delineated the anatomical relationship of these masses to the vagina, urethra and rectum.

CONCLUSIONS

Transvaginal 2D and 3D ultrasonography is an accurate, non-invasive, cost-effective diagnostic modality for the delineation of congenital, septic and neoplastic lower urogenital tract perineal masses in women.

Persistence of microbial contamination on transvaginal ultrasound probes despite low-level disinfection procedure

AIM OF THE STUDY

In many countries, Low Level Disinfection (LLD) of covered transvaginal ultrasound probes is recommended between patients' examinations. The aim of this study was to evaluate the antimicrobial efficacy of LLD under routine conditions on a range of microorganisms.

MATERIALS AND METHODS

Samples were taken over a six month period in a private French Radiology Center. 300 specimens derived from endovaginal ultrasound probes were analyzed after disinfection of the probe with wipes impregnated with a quaternary ammonium compound and chlorhexidine. Human papillomavirus (HPV) was sought in the first set of s100 samples, Chlamydia trachomatis and mycoplasmas were searched in the second set of 100 samples, bacteria and fungi in the third 100 set samples. HPV, C. trachomatis and mycoplasmas were detected by PCR amplification. PCR positive samples were subjected to a nuclease treatment before an additional PCR assay to assess the likely viable microorganisms. Bacteria and fungi were investigated by conventional methods.

RESULTS

A substantial persistence of microorganisms was observed on the disinfected probes: HPV DNA was found on 13% of the samples and 7% in nuclease-resistant form. C. trachomatis DNA was detected on 20% of the probes by primary PCR but only 2% after nuclease treatment, while mycoplasma DNA was amplified in 8% and 4%, respectively. Commensal and/or environmental bacterial flora was present on 86% of the probes, occasionally in mixed culture, and at various levels (10->3000 CFU/probe); Staphylococcus aureus was cultured from 4% of the probes (10-560 CFU/probe). No fungi were isolated.

CONCLUSION

Our findings raise concerns about the efficacy of impregnated towels as a sole mean for disinfection of ultrasound probes. Although the ultrasound probes are used with disposable covers, our results highlight the potential risk of cross contamination between patients during ultrasound examination and emphasize the need for reviewing the disinfection procedure.

Green synthesis of silver nanoparticles by Chrysanthemum morifolium Ramat. extract and their application in clinical ultrasound gel

Eco-friendly green synthesis with plant extracts plays a very important role in nanotechnology, without any harmful chemicals. In this report, the synthesis of water-soluble silver nanoparticles was developed by treating silver ions with Chrysanthemum morifolium Ramat. extract at room temperature. The effect of the extract on the formation of silver nanoparticles was characterized by ultraviolet and visible absorption spectroscopy, X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The ultraviolet and visible absorption spectroscopy results show a strong resonance centered on the surface of silver nanoparticles (AgNP) at 430 nm. The Fourier transform infrared spectroscopy spectral study demonstrates Chrysanthemum morifolium Ramat. extract acted as the reducing and stabilizing agent during the synthesis. The X-ray diffraction analysis confirmed that the synthesized AgNP are single crystallines, corresponding with the result of transmission electron microscopy. Water-soluble AgNP, with an approximate size of 20 nm–50 nm were also observed in the transmission electron microscopy image. The bactericidal properties of the synthesized AgNP were investigated using the agar-dilution method and the growth-inhibition test. The results show the AgNP had potent bactericidal activity on Staphylococcus aureus and Escherichia coli, as well as a strong antibacterial activity against gram-negative bacteria, as compared to gram-positive bacteria with a dose-dependent effect, thus providing a clinical ultrasound gel with bactericidal property for prevention of cross infections.