J

Et

K

a

2b

Ac

d

R

2

d

1

h

ournal of Infection and Public Health (2014) 7, 153—160

valuation of an automated high-level disinfectionechnology for ultrasound transducers

aren Vickerya,∗, Vivian Zaiya Gorgisb, Jon Burdachc, Dipika Pateld

Surgical Infection Research Group, Australian School of Advanced Medicine, Macquarie University, NSW109, AustraliaSydney Medicine School, Department of Infectious Disease, University of Sydney, Sydney, NSW 2006,ustraliaIceclam Pty. Ltd., PO Box 366, French’s Forest, NSW 1640, AustraliaNanosonics Ltd., Unit 24, 566 Gardeners Road, Alexandria, NSW 2015, Australia

eceived 22 May 2013; received in revised form 5 September 2013; accepted 30 September 2013

KEYWORDSUltrasound;Reprocessing;High-level disinfection;Trophon;HLD

SummaryBackground: Ultrasound transducer reprocessing is required to prevent the transmis-sion of infections between patients. In some regions, reprocessing practices are notsufficient to achieve high-level disinfection (HLD), which can result in contaminatedprobes. Furthermore, current manual HLD methods use toxic chemicals and areprone to operator error/variability. The development of automated, non-toxic HLDdisinfection devices may reduce the risk of transmission and reduce safety risks foroperators and patients. This study investigated the disinfection efficacy of a hydro-gen peroxide-based, automated HLD device, the Trophon® EPR, against a range ofinternational standards.Methods: Disinfection efficacy was assessed in carrier and simulated use tests against21 different species of bacteria, fungi and viruses. Carrier tests were performedby placing carriers throughout the disinfection chamber and measuring the logreduction in viable organisms following disinfection. These tests were performedaccording to Association of Analytical Communities International Official Meth-

ods and European and ASTM International Standards for bactericidal, fungicidal,mycobactericidal, sporicidal and virucidal disinfection. Simulated use tests involv-ing the disinfection of six widely used ultrasound probe models were conductedaccording to ASTM-E1837-96 using Mycobacterium terrae as a test organism.Results: The device satisfied criteria for HLD and sporicidal disinfection efficacyunder all standards tested.

∗ Corresponding author at: Australian School of Advanced Medicine, Macquarie University, 2 Technology Place, North Ryde, NSW109, Australia. Tel.: +61 2 9812 3550.

E-mail addresses: karen.vickery@mq.edu.au (K. Vickery), vgorgis@yahoo.com (V.Z. Gorgis), jburdach@gmail.com (J. Burdach),ipika patel@nanosonics.com.au (D. Patel).

876-0341/$ — see front matter © 2013 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

ttp://dx.doi.org/10.1016/j.jiph.2013.09.008

154 K. Vickery et al.

Conclusions: Automated, hydrogen peroxide-based disinfection devices offer an alter-native to manual ultrasound probe disinfection technologies. Such devices reduce the

nd can improve patient and operator safety by preventingicals. The adoption of next-generation disinfection devicesfection risk and improve patient safety.dulaziz University for Health Sciences. Published by Elsevier

aauw[rlcrttiaftw

wa(patTraidppltrtitp

trdevice evaluated in this paper uses a nebulizedmist of 35% hydrogen peroxide to disinfect ultra-

risks of operator error aexposure to toxic chemmay help to decrease in© 2013 King Saud Bin AbLtd. All rights reserved.

Introduction

Ultrasound transducers are reusable medicaldevices that require appropriate reprocessingbetween patients to prevent the transmission ofinfectious disease. Medical devices can be catego-rized based on the infection risk associated withtheir intended use according to the Spaulding classi-fication system [1,2]. Under this system, ultrasoundtransducers that contact broken skin or mucousmembranes are classified as semi-critical devicesand are required to undergo a minimum of high-level disinfection (HLD) between patients. HLD isgenerally defined as a complete elimination of allmicroorganisms although small numbers of bacte-rial spores may remain. HLD is therefore requiredfor a range of common ultrasound proceduresincluding, among others, intracavity ultrasound,such as transvaginal and transrectal ultrasonogra-phy, and surface ultrasound on broken skin (ulcersand wounds).

There are two main approaches to preventingthe transmission of infection between patientsundergoing such procedures. The first involves cov-ering the ultrasound transducer with a disposablephysical barrier (an ultrasound transducer coveror condom). The second method involves manualcleaning of the transducer followed by chemicaltreatment to disinfect the device. Dependingon local regulations, some combination of thesetwo methods is used to reprocess ultrasoundtransducers. However, recent studies have shownthat current approaches are not always adequate.A number of studies have examined transducercover or condom perforation and have found thatperforation is common (0.9—9%), resulting in asignificant risk of transmission [3—7]. As a result, itis mandated in the USA, Canada and Australia thatintracavity ultrasound transducers be subjectedto HLD reprocessing in addition to the use ofultrasound transducer covers. Practices in otherregions are much more variable. A recent UK study

examined transvaginal ultrasound probe (TVUSP)reprocessing practices in 68 healthcare institutionsand found that none met standards for HLD andthat reprocessing techniques were inconsistent

s(ha

cross clinics [8]. In addition, studies in Hong Kongnd France, among other places, have shown thatltrasound transducers may still be contaminatedith infectious agents following reprocessing

9—11]. This carryover is largely attributable toeprocessing techniques that are only capable ofow-level disinfection, highlighting the need forlear guidelines for transducer reprocessing. Aecent meta-analysis of the infection risk posed byransvaginal and transrectal ultrasonography foundhat across multiple studies, TVUSPs were contam-nated with pathogenic bacteria and viruses with

pooled prevalence of 12.9% and 1%, respectively,ollowing reprocessing. For patients undergoingransrectal ultrasound and guided biopsy, thereas a pooled infection rate of 3.1% [10].The resistance to adopting HLD in those regions

here it is not mandated has been attributed to number of problems, including increased toxicityresidual chemical exposure for patients and work-lace risks for reprocessing staff), time-intensivend costly disinfection procedures and the poten-ial to shorten the life of the transducer [11].hese problems arise from the manual nature ofeprocessing and the use of toxic chemicals thatre required due to the sensitive materials usedn ultrasound transducer construction. Commonisinfectants include glutaraldehyde, aldehydes,eracetic acid and quaternary ammonium com-ounds. Typically, such disinfectants require aengthy reprocessing time involving soaking theransducer for 10—20 min followed by washing toemove the disinfectants before re-use. Due to theoxicity of many chemicals used for HLD, reprocess-ng is often conducted in a separate room, addingo the time and cost demands of implementing suchrocesses in the clinic.

To address these challenges to adopting rou-ine and effective HLD procedures, new automatedeprocessing systems are becoming available. The

ound transducers in an automated 7 min cycleFig. 1). The disinfection process results in theydrogen peroxide being broken down into oxygennd water, minimizing toxicity and environmental

Evaluation of an automated high-level disinfection technology for ultrasound transducers 155

F estep ated

ibedmwrvi

M

TccdssonueaN

A

TeAiwitt

sbuwo(ITiG

C

Btaa[vwMttoacOg

mcp

igure 1 The ultrasound transducer disinfection device teroxide to disinfect ultrasound transducers in an autom

mpact with the added benefit that the device cane installed at the point of care. The efficacy ofxisting manual HLD reprocessing techniques is wellocumented [12,13]. However, the efficacy of auto-ated devices that use hydrogen peroxide is lessell established. We set out to evaluate the bacte-

icidal, mycobactericidal, sporicidal, fungicidal andirucidal efficacy of the device against a range ofnternational standards for HLD.

aterials and methods

o assess the disinfection efficacy of the device, aomprehensive range of microbiological tests wasonducted in accordance with international stan-ards for HLD. The range of organisms tested waselected based on their use as previously well-tudied indicators for disinfection efficacy and/orn their clinical significance. Appropriate sampleumbers were determined depending on the partic-lar standard tested. The standards against whichfficacy was tested represent the most widelyccepted standards for disinfection efficacy inorth America, Europe and internationally.

utomated HLD reprocessing device

he ultrasound transducer reprocessing devicevaluated was the Trophon® EPR (Nanosonics Ltd.,ustralia) (Fig. 1). The device was operated accord-

ng to the manufacturer’s instructions, and testing

as carried out using both inoculated carriers and

noculated ultrasound transducers (simulated useests). Carrier tests were conducted using a cus-omized carrier stand that placed carriers at various

otfw

d in this study (Trophon® EPR). This device uses hydrogen cycle.

patially representative points within the cham-er. All carrier and simulated use tests were runsing a standard processing cycle. Efficacy testingas conducted at four testing centers: AMS Lab-ratories, Australia (AMS); Nanosonics, AustraliaNAN); Biotech Germande, France (BG); and thenstitute of Medical Microbiology and Hygiene,übingen University, Germany (TU). The device

s currently available in the USA, UK, France,ermany, Australia and New Zealand.

arrier tests — AOAC Official Methods

actericidal carrier tests were conducted accordingo AOAC Official Methods 991.47, 991.48 and 991.49gainst Salmonella choleraesuis, Staphylococcusureus and Pseudomonas aeruginosa, respectively14—16]. Methicillin-resistant S. aureus (MRSA) andancomycin-resistant Enterococcus (VRE) strainsere tested using AOAC Official Method 991.47.ycobactericidal tests were carried out according

o AOAC Official Method 965.12 against Mycobac-erium terrae [17]. Fungicidal tests were carriedut according to AOAC Official Method 955.17gainst Trichophyton mentagrophytes, and spori-idal tests were carried out according to AOACfficial Method 966.04 against Clostridium sporo-enes and Bacillus subtilis [18,19].

Inocula were prepared according to the afore-entioned AOAC Official Methods. The organic

hallenge was initiated by 5% horse serum. Glassenicylinders, porcelain penicylinders, suture loops

r glass slide carriers were inoculated as perhe AOAC methods, and test carriers were trans-erred onto a customized stand (Fig. 2A) for testingithin the device. A standard disinfection cycle was

156 K. Vickery et al.

Figure 2 Carrier stage setups used to test the disinfection efficacy of the ultrasound transducer reprocessing device. peni

ApV1pfwa1utsalti

S

Aioihsfwiotwaacw

(A) Carrier stage used for AOAC tests loaded with a glassa plastic carrier.

run, and the carriers were recovered. Sporicidaltests were subjected to an extended 20 min dis-infectant contact time according to AOAC 966.04.Post-processing, carriers were transferred to theappropriate broth supplemented with 125 IU/mLof catalase to neutralize any residual hydrogenperoxide activity. Samples were then cultured asper the AOAC methods, with results reported asgrowth or no growth. Control samples were alsorun in accordance with the AOAC Official Methodsto establish viable counts for the initial inoc-ula.

Carrier tests — EN and ASTM standards

Bactericidal and sporicidal tests were carriedout according to the European standard EN14561against S. aureus, P. aeruginosa, Enterococcushirae, MRSA, VRE, Geobacillus stearothermophilusand Clostridium difficile [20]. Fungicidal testswere carried out in accordance with EN14562against Candida albicans and Aspergillus niger [21].Mycobactericidal tests were carried out accordingto EN14563 against Mycobacterium avium and M.terrae [22].

Inocula were prepared according to the afore-mentioned European standards. The organic chal-lenge substituted 5% horse serum for 5% BSA.Carriers were hard polymer plastic and were30 mm × 20 mm × 2 mm in dimension. Inocula werespread onto a marked surface of 20 × 20 mm andallowed to dry before being loaded onto the cus-tomized carrier stand (Fig. 2B) for transfer tothe device. Carriers were subjected to a stan-dard disinfection cycle and were transferred to theappropriate broth supplemented with 125 IU/mL ofcatalase to neutralize any residual hydrogen perox-

ide activity. The carriers were cultured as per therelevant standard, and the results are expressed asthe mean log reduction in viable organism countversus the control.

wtwp

cylinder. (B) Carrier stage used for EN tests loaded with

Virucidal tests were carried out according toSTM-E1053 against poliovirus (Type 1), herpes sim-lex virus (Type 1) and hepatitis A virus [23].iral suspensions were prepared as per ASTM-053 and were used to inoculate 60 mm circularlastic carriers. Carriers were dried and then trans-erred to the customized carrier stand. The carriersere subjected to a standard disinfection cyclend recovered with fetal bovine serum containing25 IU/mL catalase solution to neutralize any resid-al hydrogen peroxide activity before being appliedo Vero cells to detect residual infectivity. Testamples were compared with controls to achieve

mean log reduction in infection-competent viraload. Cytotoxicity controls were also run to ensurehat any cell death could be attributed to viralnfection alone.

imulated use tests

ll simulated use tests were carried out accord-ng to ASTM-E1837-96 using M. terrae as the testrganism [24]. Ultrasound transducers were dis-nfected before inoculation by soaking in 7.5%ydrogen peroxide solution for 10 min followed byoaking in a sterile solution of catalase (125 IU/mL)or 10 min and finally soaking in sterile deionizedater for 10 min. Inocula were prepared accord-

ng to ASTM-E1837-96 using 5% horse serum as therganic challenge. Four 20 mm × 30 mm regions onhe transducer handle, body (one on each side) andindow were inoculated with organism and werellowed to dry. Following drying, the inoculatedrea on the handle was swabbed to establish theontrol count prior to disinfection. The transduceras then transferred to the disinfection device and

as subjected to a standard reprocessing cycle. The

ransducer was recovered, and the remaining areasere swabbed and transferred to 7H9 broth sup-lemented with 125 IU/mL catalase to inactivate

Evaluation of an automated high-level disinfection technology for ultrasound transducers 157

Table 1 Carrier tests based on AOAC Official Methods.

Standard Testing centera n (carriers) Growth Pass/failb

Bactericidal — Glass penicylindersS. aureus ATCC 6538 AOAC 991.48 NAN 60 1 PassP. aeruginosa ATCC 15442 AOAC 991.49 NAN 60 0 PassS. choleraesuis ATCC 10708 AOAC 991.47 NAN 60 1 PassMRSA ATCC 43300 AOAC 991.47 NAN 10 0 PassMRSA ATCC 29247 AOAC 991.47 NAN 10 0 PassMRSA clinical isolate AOAC 991.47 AMS 10 0 PassVRE ATCC 51299 AOAC 991.47 NAN 10 0 PassVRE clinical isolate AOAC 991.47 AMS 10 0 Pass

Mycobactericidal — Porcelain PenicylindersM. terrae ATCC 15775 AOAC 965.12 NAN 40 0 Pass

Sporicidal — Porcelain PenicylindersC. sporogenes ATCC 3584 AOAC 966.04 AMS 180 0 PassC. sporogenes ATCC 3584 AOAC 966.04 NAN 180 0 PassB. subtilis ATCC 19659 AOAC 966.04 NAN 180 0 Pass

Sporicidal — Suture LoopsC. sporogenes ATCC 3584 AOAC 966.04 AMS 180 0 PassC. sporogenes ATCC 3584 AOAC 966.04 NAN 180 0 PassB. subtilis ATCC 19659 AOAC 966.04 AMS 120 0 PassB. subtilis ATCC 19659 AOAC 966.04 NAN 180 0 Pass

Fungicidal — Glass SlideT. mentagrophytes ATCC 9533 AOAC 955.17 NAN 10 0 Pass

omycralia.

atrvt

R

C

Tasrcoioff

C

Tfd

lmtaTc

S

TtTatttu

D

T

MRSA = Methicillin resistant Staphylococcus aureus; VRE = Vanca AMS = ams Laboratories, Australia; NAN = Nanosonics, Austb Based on AOAC criteria.

ny residual hydrogen peroxide. The solutions werehen cultured according to ASTM-E1837-96, and theesults are reported as the mean log reduction iniable organism count over the control across thehree inoculation sites.

esults

arrier tests — AOAC Official Methods

he carrier test results of the tests performedccording to the AOAC Official Methods are pre-ented in Table 1. All controls were within normalanges, and all samples tested passed the efficacyut-offs set by the relevant AOAC Official Meth-ds for HLD. Based on these results, the devices capable of HLD under the AOAC Official Meth-ds. Additionally, the device satisfies the criteriaor sporicidal claims with an extended 20 min disin-ectant contact time.

arrier tests — EN and ASTM standards

able 2 shows the results of the carrier tests per-ormed according to the European and ASTM stan-ards. The mean log reduction in viable organism

tudu

in resistant Enterococcus.

oad after disinfection and the standard error of theean (SEM) were calculated for each of the carrier

est cycles. All controls were within normal ranges,nd all samples tested passed the efficacy cut-offs.hese data indicate that the device satisfies theriteria for HLD under both EN and ASTM standards.

imulated use tests

he results of tests simulating worst-case condi-ions under ASTM-E1837-96 are shown in Table 3.he mean log reduction in viable organism countnd the SEM were calculated for each simulated useest. The mycobacterial load was reduced by morehan 6 log in all cases. These results indicate thathe device is capable of HLD under the simulatedse conditions.

iscussion

he efficacy results showed that the device consis-

ently achieved HLD in both carrier and simulatedse tests using typical intracavity ultrasound trans-ucers. Aspects of the testing methodologiessed were more challenging than would likely be

158 K. Vickery et al.

Table 2 Carrier tests based on EN and ASTM standards.

Standard Testingcentera

n(cycles)

Mean logreduction

SEM Pass/failb

BactericidalS. aureus ATCC 6538 EN14561 AMS 12 6.92 0.09 PassS. aureus ATCC 6538 EN14561 NAN 6 7.40 0.00 PassS. aureus ATCC 6538 EN14561 TU 5 6.68 0.12 PassS. aureus CIP 4.83 EN14561 BG 3 6.40 0.06 PassP. aeruginosa ATCC 15442 EN14561 AMS 6 6.10 0.04 PassP. aeruginosa ATCC 15442 EN14561 NAN 6 6.25 0.02 PassP. aeruginosa ATCC 15442 EN14561 TU 5 6.79 0.02 PassE. hirae ATCC 10541 EN14561 AMS 6 6.67 0.28 PassE. hirae ATCC 10541 EN14561 NAN 6 7.00 0.22 PassE. hirae ATCC 10541 EN14561 TU 5 6.63 0.10 PassMRSA ATCC 43300 EN14561 NAN 3 6.97 0.00 PassMRSA ATCC 29247 EN14561 NAN 3 6.80 0.00 PassVRE ATCC 51299 EN14561 NAN 3 6.15 0.00 Pass

MycobactericidalM. avium ATCC 15769 EN14563 AMS 6 7.25 0.02 PassM. avium ATCC 15769 EN14563 NAN 6 6.85 0.02 PassM. avium ATCC 15769 EN14563 TU 5 6.52 0.00 PassM. terrae ATCC 15775 EN14563 AMS 12 7.13 0.01 PassM. terrae ATCC 15775 EN14563 NAN 6 6.55 0.02 PassM. terrae ATCC 15775 EN14563 TU 5 6.02 0.28 PassM. terrae CIP 104321 EN14563 BG 3 6.07 0.03 Pass

SporicidalG. stearothermophilus ATCC 7953 EN14561 AMS 6 6.75 0.34 PassG. stearothermophilus ATCC 7953 EN14561 NAN 6 6.10 0.04 PassG. stearothermophilus ATCC 7953 EN14561 BG 3 6.23 0.07 PassC. difficile ATCC 43593 EN14561 NAN 3 6.23 0.05 Pass

FungicidalC. albicans ATCC 10231 EN14562 AMS 6 5.48 0.22 PassC. albicans ATCC 10231 EN14562 NAN 6 5.38 0.15 PassA. niger ATCC 16404 EN14562 AMS 6 5.47 0.22 PassA. niger ATCC 16404 EN14562 NAN 6 6.28 0.24 PassA. niger IP 1431.83 EN14562 BG 3 5.93 0.03 Pass

VirucidalPolio Virus Type 1 (ATCC VR-192) ASTM E 1053-11 AMS 7 4.29 0.20 PassPolio Virus Type 1 (ATCC VR-192) ASTM E 1053-11 NAN 10 4.18 0.05 PassPolio Virus Type 1 (ATCC VR-192) ASTM E 1053-11 BG 4 4.28 0.05 PassHerpes Simplex Virus Type 1 ATCC VR-733 ASTM E 1053-11 AMS 6 3.85 0.29 Passc

Herpes Simplex Virus Type 1 ATCC VR-733 ASTM E 1053-11 NAN 4 4.00 0.00 PassHepatitis A Virus ATCC CRL-1688 ASTM E 1053-11 AMS 2 4.35 0.15 Pass

MRSA = Methicillin-resistant Staphylococcus aureus; VRE = Vancomycin-resistant Enterococcus; SEM = Standard error of the mean.a AMS = ams Laboratories, Australia; NAN = Nanosonics, Australia; BG = Biotech Germande, France; TU = Tübingen University,

Germany.

atut

b Based on EN or ASTM criteria.c Cytotoxicity >2; >3 log reduction required for pass.

encountered in real-world disinfection practices.All penicylinder tests incorporated the presence ofmated surfaces where the penicylinders contactedthe carrier stand. Such contact points are diffi-

cult to disinfect and are the likely cause of thelow levels of breakthrough growth of S. aureus andS. choleraesuis (however, the results still met the

brB

cceptance criteria for HLD) (Table 1). To increasehe realism of the tests, appropriate materials weresed where possible. All tests performed accordingo EN standards used plastic carriers (acrylonitrile

utadiene styrene) that are typical of those mate-ials used in ultrasound transducer construction.ased on the broad efficacy observed under the

Evaluation of an automated high-level disinfection technology for ultrasound transducers 159

Table 3 Simulated use tests on a range of widely used transvaginal ultrasound transducers.

Manufacturer Ultrasound transducermodel

Testingcentera

n (transducers) Mean logreduction

SEM Pass/failb

ATL Linear Array L11-5 AMS 4 7.14 0.12 PassATL Linear Array L11-5 NAN 2 6.99 0.21 PassGE 3.5C NAN 1 7.13 N/A PassAcuson C3 AMS 2 7.35 0.05 PassGE 618E, Model: 2197484 AMS 2 7.20 0.10 PassATL Curved Array C9-5 ICT AMS 2 6.80 0.20 PassMedison L3 probe AMS 2 6.91 0.04 Pass

SEM = Standard error of the mean.a AMS = ams Laboratories, Australia; NAN = Nanosonics, Australia.b Based on ASTM-E1837-96 criteria.

rns

ptearcwmiftTpoaeamcattCvmwbmri

lsit

cwej

hogtavsbuuaw

D

Dnwfi

R

Nwati

ange of tests conducted, the device offers an alter-ative to users of traditional manual disinfectionolutions.

The testing of large numbers of replicate sam-les across multiple testing centers allowed forhe analysis of the consistency of the disinfectionfficacy. The SEM for both AOAC Official Methodsnd simulated use tests was low (less than 0.4 logeductions in viable count across all samples), indi-ating that the device tested is able to achieve HLDith a low degree of variability. Such consistencyay offer advantages over manual HLD reprocess-

ng methods, which may provide more opportunitiesor operator error or variation. During a study onhe human papilloma virus (HPV) contamination ofVUSPs in Hong Kong, researchers noted that theroportion of HPV-positive transducers dropped offver the course of the study [9]. Importantly, theuthors attributed this improvement in disinfectionfficacy to the staff becoming aware of the studynd therefore changing their behavior and beingore stringent in performing the disinfection pro-

edure. Such human variation is not unexpected,nd some regulatory agencies have set guidelineshat give preference to reprocessing techniqueshat are performed in an automated fashion. Theommission for Hospital Hygiene and Infection Pre-ention in Germany recommends that automatedethods for reprocessing medical devices be usedhere possible [25]. Similarly, UK guidelines set outy the Department of Health recommend that theanual reprocessing of medical devices should be

estricted to those items that cannot be processedn an automated manner [26].

The experiments presented herein all involvedab-based testing with heavy inocula and organic

oiling in an effort to represent worst-case scenar-os in clinical practice. Although these lab-basedests are widely accepted as evidence of efficacy,

E

N

linical studies that examine performance in a real-orld setting would be desirable to fully investigatefficacy. Such clinical investigations will be the sub-ect of future work.

In conclusion, automated devices that utilizeydrogen peroxide-based disinfection technologyffer advantages to users and patients. Hydro-en peroxide offers a less toxic alternativeo glutaraldehyde-based disinfection technologies,nd automation reduces the chance of operatorariability in reprocessing. The results from thistudy show that automated, hydrogen peroxide-ased reprocessing devices can achieve HLD ofltrasound probes in both carrier and simulated-se tests. Given the safety benefits to operatorsnd patients, such devices will likely become moreidely used in the future.

isclosure statement

P is an employee of Nanosonics Ltd. JB is an exter-al consultant to Nanosonics Ltd. The manuscriptas written by the authors, and approval of thenal manuscript by Nanosonics was not required.

ole of the funding source

anosonics Ltd. provided funding for this study andas involved in the study design, data analysisnd writing of the manuscript. Some experimentalesting was carried out at Nanosonics’ facilities asndicated in the data tables.

thical approval

ot required.

[

[

[

[

[

[

[

[

[

[

[

160

References

[1] Spaulding EH. Chemical disinfection and antisepsis in thehospital. J Hosp Res 1957;9:5—31.

[2] Rutala WA, Weber DJ. Infection control: the role ofdisinfection and sterilization. J Hosp Infect 1999;(43Suppl.):S43—55.

[3] Storment JM, Monga M, Blanco JD. Ineffectivenessof latex condoms in preventing contamination of thetransvaginal ultrasound transducer head. South Med J1997;90(2):206—8.

[4] Masood J, Voulgaris S, Awogu O, Younis C, Ball AJ, Carr TW.Condom perforation during transrectal ultrasound guided(TRUS) prostate biopsies: a potential infection risk. Int UrolNephrol 2007;39(4):1121—4.

[5] Milki AA, Fisch JD. Vaginal ultrasound probe coverleakage: implications for patient care. Fertil Steril1998;69(3):409—11.

[6] Rooks VJ, Yancey MK, Elg SA, Brueske L. Comparison ofprobe sheaths for endovaginal sonography. Obstet Gynecol1996;87(1):27—9.

[7] Amis S, Ruddy M, Kibbler CC, Economides DL, MacLeanAB. Assessment of condoms as probe covers fortransvaginal sonography. J Clin Ultrasound 2000;28(6):295—8.

[8] Gray RA, Williams PL, Dubbins PA, Jenks PJ. Decontamina-tion of transvaginal ultrasound probes: review of nationalpractice and need for national guidelines. Clin Radiol2012;67(11):1069—77.

[9] Ma ST, Yeung AC, Chan PK, Graham CA. Transvaginalultra-sound probe contamination by the human papillo-mavirus in the emergency department. Emerg Med J Jun2013;30(6):472—5.

[10] Leroy S. Infectious risk of endovaginal and transrectal ultra-sonography: systematic review and meta-analysis. J HospInfect Feb 2013;83(2):99—106.

[11] Casalegno JS, Le Bail Carval K, Eibach D, Valdeyron ML,Lamblin G, Jacquemoud H, et al. High risk HPV con-tamination of endocavity vaginal ultrasound probes: anunderestimated route of nosocomial infection? PLoS One2012;7(10):e48137.

[12] Hernandez A, Carrasco M, Ausina V. Mycobactericidal activ-ity of chlorine dioxide wipes in a modified prEN 14563 test.J Hosp Infect 2008;69(4):384—8.

[13] Stevens AB. Aldehyde disinfectants and health in endoscopyunits. Gut 1994;35(5):717.

[14] AOAC International. AOAC Official Method 991.47 TestingDisinfectants against Salmonella choleraesuis Hard SurfaceCarrier Test Method. Official Methods of Analysis of AOACInternational; 2006.

[

Available online at www

ScienceD

K. Vickery et al.

15] AOAC International. AOAC Official Method 991.49 TestingDisinfectants against Pseaudomonas aeruginosa Hard Sur-face Carrier Test Method. Official Methods of Analysis ofAOAC International; 2006.

16] AOAC International. AOAC Official Method 991.48 TestingDisinfectants against Staphylococcus aureus Hard SurfaceCarrier Test Method. Official Methods of Analysis of AOACInternational; 2006.

17] AOAC International. AOAC Official Method 965.12 Tubercu-locidal Activity of Disinfectants. Official Methods of Analysisof AOAC International; 2008.

18] AOAC International. AOAC Official Method 955.17 FungicidalActivity of Disinfectants Using Trichophyton mentagro-phytes. Official Methods of Analysis of AOAC International;2006.

19] AOAC International. AOAC Official Method 966.04 Sporici-dal Activity of Disinfectants Method I. Official Methods ofAnalysis of AOAC International; 2006.

20] Comite Europeen de Normalisation. EN14561:2008 Chemi-cal Disinfectants and Antiseptics — Quantitative Carrier Testfor the Evaluation of Bactericidal Activity for Instrumentsused in the Medical Area — Test Method and Requirements.Comite Europeen de Normalisation; 2008.

21] Comite Europeen de Normalisation. EN14562:2008 Chemi-cal Disinfectants and Antiseptics — Quantitative Carrier Testfor the Evaluation of Fungicidal or Yeasticidal Activity forInstruments used in the Medical Area — Test Method andRequirements. Comite Europeen de Normalisation; 2008.

22] Comite Europeen de Normalisation. EN14563:2009 Chemi-cal disinfectants and antiseptics — Quantitative Carrier Testfor the Evaluation of Mycobactericidal or TuberculocidalActivity of Chemical Disinfectants used for Instruments inthe Medical Area — Test Method and Requirements; 2009.

23] ASTM International. A.S.T.M E1053 — 11 Standard TestMethod to Assess Virucidal Activity of Chemicals Intendedfor Disinfection of Inanimate, Nonporous EnvironmentalSurfaces; 2011.

24] ASTM International. ASTM E1837 — 96(2007) Standard TestMethod to Determine Efficacy of Disinfection Processes forReusable Medical Devices (Simulated Use Test); 2007.

25] Commission for Hospital Hygiene and Infection Prevention(Robert Koch Institute). Anforderungen an die Hygiene beider Aufbereitung von Medizinprodukten (Hygiene Require-ments for Reprocessing Medical Devices — Recommendationof the Commission for Hospital Hygiene and Infection Pre-vention at the Robert Koch Institute (RKI).), Section 2.2.1Preparation of Reprocessing, Cleaning/Disinfection, Rinsing

and Drying; 2010.

26] Department of Health (UK). HTM 01-01: Decontaminationof reusable medical devices: Part A, Paragraph 2.2; 2007.

.sciencedirect.com

irect