Are probe sheaths and low level decontamination enough to prevent microbial contamination of ultrasound probe during transvaginal ultrasound?
Date First Published:
January 21, 2015
Last Updated:
January 28, 2015
Report by:
Mireille Paradis, PGY-4 Emergency Medicine (Laval University)
Search checked by:
Marc Charles Parent, Laval University
Three-Part Question:
When [transvaginal ultrasound is performed in the emergency department] do [current practices of low-level decontamination and use of probe sheaths] prevent [microbial contamination] ?
Clinical Scenario:
A 25 years old woman presents to the ER with a chief complaint of first trimester vaginal bleeding. Her vitals are unremarkable. You perform a transvaginal ultrasonography using a condom on the probe and confirm the presence of an intrauterine pregnancy. Once the exam is completed, you clean the probe. You wonder if probe sheaths and low level decontamination were studied regarding microbial contamination.
Search Strategy:
Bestbets
Cochrane
Medline via pubmed (French and English)
Embase
References were reviewed
Cochrane
Medline via pubmed (French and English)
Embase
References were reviewed
Search Details:
No best bets found
No Cochrane review found
Medline: 1960/01/01 to 2015/01t/01 via pubmed,
-tFilters : French and English
1.tEndosonography {MeSH}: 9086
2.tUltrasonography, prenatal {MeSH} : 25696
3.tUltrasonography {MeSH} : 252514
4.tEmergency service, Hospital {MeSH} : 50527
5.tCross infection {MeSH} : 47394
6.tEquipment contamination {MeSH} : 9989
7.tCondom {MeSH} : 7084 no filters
8.tTransvaginal ultrasonography : 5849
9.tEndovaginal ultrasound: 471
10.tEndovaginal ultrasonography: 413
11.tTransvaginal ultrasound: 7094
12.tTransvaginal ultrasonography : 5849
13.tEmergency Medical Service {MeSH} : 97119
14.tEndocavitary ultrasound probe contamination : 1
15.tEndocavitary ultrasound probe infection : 5
16.tVaginal probe cover : 10
17.t1 + 4 : 8
18.t1+13 : 12
19.t1+5 : 2
20.t1+6: 5
21.t1+7 : 2
22.t1+4+5: 0
23.t1+13+5 : 0
24.t1+13 + 5: 0
25.t1+4+6: 0
26.t1+4+5: 0
27.t1+4+6: 0
28.t2+4 : 38
29.t2+4+5 : 0
30.t2+4+6 : 0
31.t3+5 : 115
32.t3+6 : 85
33.t3+4 : 775
34.t3+4+5 : 5
35.t3+4+6: 7
36.t3+6+7 : 2
37.t4+5+8 : 1
38.t8+7 : 1
39.t8+6: 4
40.t8+7 : 5
41.t9+5: 2
42.t9+6 : 4
43.t9+7 : 1
44.t10+5: 2
45.t10+6:4
46.t10 + 7 : 1
47.t11+5 : 1
48.t11+ 6: 4
49.t11+7:5
50.t12+5 : 1
51.t12+6 : 4
52.t12+7 : 5
53.t7+9 : 1
54.t1+7 : 2
55.t1+6+7 : 0
-tEmbase : < 1966 to 2015
-tFilters :
1.tEndosonography: 19157
2.tTransvaginal AND ultrasound: 9 049
3.tTransvaginal AND ultrasonography : 3 667
4.tEndovaginal ANDN ultrasonography: 196
5.tEndovaginal ultrasound: 457
6.tEmergency department: 1 807
7.tContamination: 183 619
8.tCross AND infection: 83 517
9.tNosocomial AND infection: 27 434
10.tCondom: 20 148
11.tEndocavitary ultrasound probe infection : 5
12.tEndocavitary probe contamination: 1
13.tEndocavitary probe hygiene : 2
14.tVaginal probe cover : 11
15.t1+6+7: 0
16.t1+7 : 60
17.t1+6+8 :0
18.t1+6+9: 0
19.t2+6+7: 2
20.t2+7: 27
21.t2+10: 10
22.t2+11: 10
23.t2+6+8:0
24.t2+6+9:0
25.t3+6+7 : 1
26.t3+7 : 8
27.t3+6+8:0
28.t3+6+9:0
29.t3+10: 4
30.t4+6+7: 1
31.t4+6+8:0
32.t4+6+9:0
33.t4+10: 0
No Cochrane review found
Medline: 1960/01/01 to 2015/01t/01 via pubmed,
-tFilters : French and English
1.tEndosonography {MeSH}: 9086
2.tUltrasonography, prenatal {MeSH} : 25696
3.tUltrasonography {MeSH} : 252514
4.tEmergency service, Hospital {MeSH} : 50527
5.tCross infection {MeSH} : 47394
6.tEquipment contamination {MeSH} : 9989
7.tCondom {MeSH} : 7084 no filters
8.tTransvaginal ultrasonography : 5849
9.tEndovaginal ultrasound: 471
10.tEndovaginal ultrasonography: 413
11.tTransvaginal ultrasound: 7094
12.tTransvaginal ultrasonography : 5849
13.tEmergency Medical Service {MeSH} : 97119
14.tEndocavitary ultrasound probe contamination : 1
15.tEndocavitary ultrasound probe infection : 5
16.tVaginal probe cover : 10
17.t1 + 4 : 8
18.t1+13 : 12
19.t1+5 : 2
20.t1+6: 5
21.t1+7 : 2
22.t1+4+5: 0
23.t1+13+5 : 0
24.t1+13 + 5: 0
25.t1+4+6: 0
26.t1+4+5: 0
27.t1+4+6: 0
28.t2+4 : 38
29.t2+4+5 : 0
30.t2+4+6 : 0
31.t3+5 : 115
32.t3+6 : 85
33.t3+4 : 775
34.t3+4+5 : 5
35.t3+4+6: 7
36.t3+6+7 : 2
37.t4+5+8 : 1
38.t8+7 : 1
39.t8+6: 4
40.t8+7 : 5
41.t9+5: 2
42.t9+6 : 4
43.t9+7 : 1
44.t10+5: 2
45.t10+6:4
46.t10 + 7 : 1
47.t11+5 : 1
48.t11+ 6: 4
49.t11+7:5
50.t12+5 : 1
51.t12+6 : 4
52.t12+7 : 5
53.t7+9 : 1
54.t1+7 : 2
55.t1+6+7 : 0
-tEmbase : < 1966 to 2015
-tFilters :
1.tEndosonography: 19157
2.tTransvaginal AND ultrasound: 9 049
3.tTransvaginal AND ultrasonography : 3 667
4.tEndovaginal ANDN ultrasonography: 196
5.tEndovaginal ultrasound: 457
6.tEmergency department: 1 807
7.tContamination: 183 619
8.tCross AND infection: 83 517
9.tNosocomial AND infection: 27 434
10.tCondom: 20 148
11.tEndocavitary ultrasound probe infection : 5
12.tEndocavitary probe contamination: 1
13.tEndocavitary probe hygiene : 2
14.tVaginal probe cover : 11
15.t1+6+7: 0
16.t1+7 : 60
17.t1+6+8 :0
18.t1+6+9: 0
19.t2+6+7: 2
20.t2+7: 27
21.t2+10: 10
22.t2+11: 10
23.t2+6+8:0
24.t2+6+9:0
25.t3+6+7 : 1
26.t3+7 : 8
27.t3+6+8:0
28.t3+6+9:0
29.t3+10: 4
30.t4+6+7: 1
31.t4+6+8:0
32.t4+6+9:0
33.t4+10: 0
Outcome:
Eight relevant papers were selected out of twenty-two after reading the articles.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Transvaginal ultrasound probe contamination by the human papillomavirus in the emergency department, Ma S.T.C., Yeung A.C., Chan PKS, Graham C.A 2013 China | 1) Surveillance n = 120 2) Serial samples n=76 18 years Less than 12 weeks pregnant Chief complaint of bleeding or abdominal pain |
Two independent cross-sectional studies ED conducted |
Contamination rates from twice daily swabs for 60 days PCR for DNA detection of HPV | HPV detection (n = 120) 7,5% CI not specified Contamination higher in days 1-20 (20%) | Not blinded Little sample size Coupling gel not analysed No testing for viral load Dry cotton wool swabs stored in normal saline (loss in sensitivity) 3 consecutive swabs on probe might increase contamination by operator manipulations |
| Contamination rates (disinfection procedure : condoms removal, dry wipe then T-spray application) PCR for DNA detection of HPV | HPV detection before disinfection : 1 (1,2% CI not specified) HPV detection after disinfection in HPV positive patients on high vaginal swab (n=14): 3 | ||||
| Persistence of Microbial Contamination on Transvaginal Ultrasound Probes despite Low-Level Disinfection Procedure M’Zali F, Bounizra C, Leroy S, Mekki Y, Quentin-Noury C, et al. 2014 France | 300 Consecutive swabs of vaginal ultrasound probes | Prospective 1 private radiology center |
Contamination rate after removal of CE disposable sheaths, sterile dry wipe and disinfection with Prodene wipes PCR DNA detection | HPV (n=100): 13% (95% CI 6-20) Chlamydia trachomatis (n=100) 20% (95% CI 12-28) Mycoplasma 8% (95% CI 3-13) Commensal and/or environmental bacterial flora 86% (95% CI 79-93%) S. coagulase-Negative 73% S aureus 4% Streptococcus viridans 2% | Consecutive samples but not all three analysis performed in every sample Financial support by Germitec |
| Second PCR amplification after DNase treatment in positive sample (identification of infectious viral or bacterial particles) | HPV 7% (95% CI: 2– 12) Mycoplasmas 4% (95% CI: 0–8) C. trachomatis 2% (95% CIX-X) | ||||
| Ultrasound gel | Analysis 1/week: no significant microbial contamination | ||||
| High Risk HPV Contamination of Endocavity Vaginal Ultrasound Probes: An Underestimated Route of Nosocomial Infection Casalegno J-S, Le Bail Carval K, Eibach D, Valdeyron M-L, Lamblin G, Jacquemoud H, Mellier G, Lina B, Gaucherand P, Mathevet P, Mekki Y, 2012 France | Probe swab samples 1) After probe disinfection (n=200) 2) Before scan n=217 |
Prospective 2 studies Gynecology ward CE disposable probe cover Disinfection of probe by nurse under technician supervision |
HPV after disinfection with Sani-Cloth active PCR for DNA detection of HPV | HPV (n=198): 3,5% Sampling order : 4 subsequent samples positive for the same HPV type. | Not blinded Dry swabs : loss in sensitivity No testing for viral load Funded by Germitec |
| HPV before probe use PCR for DNA detection of HPV | HPV (n=216) : 2,8% | ||||
| Ineffectiveness of latex condoms in preventing contamination of the transvaginal ultrasound transducer head Storment JM 1997 United States | 173 women Diagnosis of threatened spontaneous abortion (n=118) possible ectopic pregnancy (n=30) pelvic pain (n=20) and pelvic mass (n=5) |
Prospective Obstetrics and gynecology residents performing transvaginal ultrasound in the ED |
Contamination inside condom | Blood or vaginal fluid visualized on probe : 3 (2%) Contamination of probe (hydrogen peroxide poured into condom, bubbling when in contact with secretions or blood) : 8 (5%) | Blood or vaginal fluid visualized on probe : 3 (2%) Contamination of probe (hydrogen peroxide poured into condom, bubbling when in contact with secretions or blood) : 8 (5%) |
| Risk of Human Immunodeficiency Virus and Hepatitis C Virus Infection Related to Endocavitary Ultrasound Probe Exposure in France Bénet T, Ritter J, Vanhems P 2014 France | Patients tested for HIV : 50 244 (Prevalence seropositivity : 1,4 %) Tested for HCV : 105 995 (Prevalence seropositivity : 3%) |
Prospective cohort of all patients tested for HIV and HCV Single center (Lyon Hospital) Endovaginal, transrectal and transoesophageal exposures |
Multivariate logistic regression adjusted for sex, age and time period | HIV prevalence not associated with previous endocavitary probe exposure (p=0,18) | Endocavitary exposure 12 months prior to testing Type of probe cover and methods of disinfection at Lyon’s Hospital not specified Ultrasounds performed in the emergency department included ? Confounder not taken into account: iv drug use, blood products transfusion |
| One or more endovaginal probe exposure prevalence and adjusted odds ratio | HIV prevalence 0,5% HCV prevalence: 1,3% HIV aOR : 1,1 (95% CI 0,4-2,6) HCV aOR : 0,8 (95% CI 0,5-1,3) | ||||
| Relative risk of seroconversion HCV in patient previously exposed to endocavitary probe | RR 0,7 (95% CI 0,1-4,8, p=0,69) | ||||
| Assessment of Condoms as Probe Covers for Transvaginal Sonography Amis S, Ruddy M, Kibbler C.C, Economides D.L., MacLean A.B. 2000 United Kingdom | 214 scans of women referred to Ovarian Cancer Screening Clinic | Prospective | Contamination of probe by routine bacterias and HSV-1 HSV-2 Transducer uncovered and wiped with a dry tissue | Bacterial swabs n =24 Viral sample n=11 1 positive for Acinetobacter sp | Swabs samples not taken systematically Criteria for sampling not specified. Not blinded |
| Contamination by routine bacterias and HSV-1 HSV-2 Transducer uncovered and wiped with dry tissue then 70% v/v isopropyl alcohol wipe | Bacterial swabs n=22 Viral swabs n=15 No bacterial /viral growth | ||||
| Condoms perforation | N=214 2 noted upon visual inspection 204 tested with hydrogen peroxide : no perforation | ||||
| Sonographic coupling gel | N=25 No growth | ||||
| Infectious risk of endovaginal and transrectal ultrasonography: systematic review and meta-analysis Leroy S 2013 France | - | Systematic review Meta-analysis |
Pooled estimate of probe contamination for transvaginal ultrasound after low level disinfection of probe (dry towel then towel combined to a disinfectant) | Prevalence of bacterial contamination (N=596) Pooled prevalence 12,9% (95% CI 1,7-24,3) Bacterias: Enterobacter sp, Acinetobacter sp, P aeruginosa, C cepacia, E Coli, S aureu Viral contamination (N=408) 1% (95% CI 0-10) HSV, CMV, HPV | Quality evaluation (eg PRISMA) of studies not presented Pooled prevalence not weighted for sample size Physician performing the ultrasound not specified |
| Evaluation of Ultraviolet C for Disinfection of Endocavitary Ultrasound Transducers Persistently Contaminated despite Probe Covers Kac G, Podglajen I, Si-Mohamed A, Rodi A, Grataloup C, Meyer G 2010 France | Bacterial analysis n =122 Viral analysis n = 336 |
Prospective 3 radiology wards |
Rate of bacterial contamination | Positive bacterial cultures after transvaginal examination (n=122) 3 2,5% (95%CI 0,5-7,3%)(Pseudomonas sp, Klebsiella pneumoniae) | No testing for viral load No explanation for difference in sample size between viral and bacterial contamination Bacterial load after UVC light disinfection not mentioned 2 types of probe covers (condoms n=267 and probe sheaths n=173) Ultrasound gel not analysed Swabs taken after probe cover removal but before cleaning with a towel impregnated with a disinfectant spray Financial support by Germitec |
| Rate of viral contamination EBV, CMV, HPV | Viral analysis (transvaginal = 90 ; transrectal n= 336) before probe removal Presence of at least 1 virus: 56 (16,7% 95%CI 13,1-21%) HPV 28 (8,3% CI not specified) Presence of viral genome in 5 (8,9% 95% CI 3,5-19,7%) of the 56 virally contaminated After removal of probe cover 1 EBV (transvaginal) | ||||
| Evaluate efficacy of disinfection combined to UVC light | No viral genome detected |
Author Commentary:
Endocavitary ultrasound is used in multiple fields in medicine (urology, gynecology, cardiology, radiology and emergency medicine). Most studies on transvaginal probe contamination were conducted on obstetrics, genecology and radiology wards. Sample sizes remain small. Various probe covers and disinfecting products were used. Ultrasound coupling gel can be contaminated, therefore, it must be analysed as a potential confounder. Three studies received financial support from Germitec, a company selling a UVC light disinfectant machine for endocavitary ultrasound probes. It is worth mentioning that presence of viral DNA differs from viral load with regards to infection propagation. Finally, dry swabs may lead to lower sensitivity in microbial detection. Studies were not blinded, consequently it may have strengthened the compliance to disinfection procedures.
Bottom Line:
Transvaginal ultrasound is a useful adjunct in evaluation of first semester vaginal bleeding in the emergency department. Use of a probe sheath is paramount but not sufficient, as condoms perforations were reported. Best evidence regarding probe contamination (M’Kazil et al, 2014) reported contamination with HPV, Mycoplasma and Chlamydia trachomatis. However, it is unkown whether this can lead to nosocomial infection. Also, it is possible that physician manipulations and environment contamination contribute to microbial propagation. Hence, in the emergency room, as in any other specialty performing endocavitary ultrasound exams, special attention with probe disinfection is needed. Specific studies regarding disinfecting procedures efficacy and surveillance for potential infection propagation are warranted.
References:
- Ma S.T.C., Yeung A.C., Chan PKS, Graham C.A . Transvaginal ultrasound probe contamination by the human papillomavirus in the emergency department,
- M’Zali F, Bounizra C, Leroy S, Mekki Y, Quentin-Noury C, et al.. Persistence of Microbial Contamination on Transvaginal Ultrasound Probes despite Low-Level Disinfection Procedure
- Casalegno J-S, Le Bail Carval K, Eibach D, Valdeyron M-L, Lamblin G, Jacquemoud H, Mellier G, Lina B, Gaucherand P, Mathevet P, Mekki Y, . High Risk HPV Contamination of Endocavity Vaginal Ultrasound Probes: An Underestimated Route of Nosocomial Infection
- Storment JM. Ineffectiveness of latex condoms in preventing contamination of the transvaginal ultrasound transducer head
- Bénet T, Ritter J, Vanhems P. Risk of Human Immunodeficiency Virus and Hepatitis C Virus Infection Related to Endocavitary Ultrasound Probe Exposure in France
- Amis S, Ruddy M, Kibbler C.C, Economides D.L., MacLean A.B. . Assessment of Condoms as Probe Covers for Transvaginal Sonography
- Leroy S. Infectious risk of endovaginal and transrectal ultrasonography: systematic review and meta-analysis
- Kac G, Podglajen I, Si-Mohamed A, Rodi A, Grataloup C, Meyer G . Evaluation of Ultraviolet C for Disinfection of Endocavitary Ultrasound Transducers Persistently Contaminated despite Probe Covers