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Persistence of microbial contamination on transvaginal ultrasound probes despite low-level disinfection procedure
Fatima M'Zali1, Carole Bounizra1, Sandrine Leroy2
1Université Bordeaux Segalen, Microbiologie Fondamentale et Pathogénicité Unité Mixte de Recherche 5234, Bordeaux, France.
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.
Insights
Low level disinfection of ultrasound probes using impregnated wipes showed significant microbial persistence, including Human papillomavirus (HPV) and bacteria. This raises concerns about cross-contamination risks and the need for improved disinfection protocols.
Area of Science:
- Microbiology
- Infectious Diseases
- Medical Device Reprocessing
Background:
- Low Level Disinfection (LLD) is standard practice for transvaginal ultrasound probes between patient uses.
- Current LLD protocols often involve wipes impregnated with quaternary ammonium compounds and chlorhexidine.
Purpose of the Study:
- To evaluate the antimicrobial efficacy of LLD under routine conditions on various microorganisms.
- To assess the effectiveness of current disinfection methods for transvaginal ultrasound probes.
Main Methods:
- A six-month study in a French radiology center analyzed 300 disinfected transvaginal ultrasound probes.
- Samples were tested for Human papillomavirus (HPV), Chlamydia trachomatis, mycoplasmas, bacteria, and fungi using PCR and conventional methods.
- Nuclease treatment was employed to differentiate between DNA presence and viable microorganisms.
Main Results:
- Significant microbial persistence was observed: HPV DNA in 13%, viable HPV in 7%.
- Chlamydia trachomatis DNA detected in 20% (viable in 2%), Mycoplasma DNA in 8% (viable in 4%).
- Bacterial flora found on 86% of probes, including Staphylococcus aureus in 4%.
Conclusions:
- Impregnated wipes alone are insufficient for effective ultrasound probe disinfection.
- Despite disposable covers, a risk of patient cross-contamination exists.
- Current ultrasound probe disinfection procedures require review and potential enhancement.
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