ORIGINAL ARTICLE

Antibacterial finishing reduces hospital textilescontamination. An experimental study

Carlo Luca Romanò & Delia Romanò & Elena De Vecchi &Nicola Logoluso & Lorenzo Drago

Received: 4 December 2011 /Accepted: 10 July 2012 /Published online: 25 July 2012# EFORT 2012

AbstractIntroduction and methods Contaminated dressings are par-ticularly suitable for growth of microorganisms and a well-known source of bacterial spreading in the hospital environ-ment. This study evaluates the bacterial contamination ofwhite coats and surgical gowns and drapes treated with anovel antibacterial finishing technology of hospital textiles.Bacterial contamination rates of untreated white coats andsurgical gowns and drapes were compared to treated textiles.In vitro determination of antibacterial activity against refer-ence bacterial strains and clinical isolates was performedaccording to the European guideline EN ISO 20645. Efficacyof the treatment was verified in clinical setting by comparingthe amount of bacteria isolated from treated and untreatedtextiles used for clinical and surgical activities.Result and conclusion Treated textiles demonstrated in vitroactivity against most of the tested microorganisms with theexception of Pseudomonas aeruginosa. Bacterial contami-

nation was markedly lower for treated white coats after1 week of use and for surgical gowns and textiles at theend of surgery when compared to untreated dressings andtextiles used in the same conditions. The tested treatmentproved to be able to reduce bacterial contamination ofhospital textiles both in vitro and in the clinical and surgicalsettings.

Keywords Textiles . Hospital . Finishing . Infection

Introduction

An important and frequent mode of transmission of patho-gens causing hospital-acquired infections is through cross-contamination between susceptible hosts and an infected orcolonized person or an infected object such as contaminatedinstruments or dressing [1–5]. Textile products can providea particularly suitable environment for growth of microor-ganisms because of their large specific surface area andcapacity to retain moisture and may be linked with patho-genic transmission in hospital settings [1, 6].

Despite current recommendations and safety proce-dures, it has been verified that methicillin-resistant Staph-ylococcus aureus, vancomycin-resistant Enterococcusfaecium and pan-resistant Acinectobacter baumannii iso-lated on white coats have the potential to contribute to thespread of hospital-associated infections [5, 7]. Therefore,the use of antibacterial agents to prevent or delay bacterialcontamination is becoming a standard finish for textilegoods.

The aim of this study was to assess, both in vitro and invivo, the antibacterial properties of hospital dressing and tex-tiles treated with a recently developed finishing technology.7

C. L. Romanò (*) :D. Romanò :N. LogolusoCentro di Chirurgia Ricostruttiva e delle Infezioni Osteo-articolari,Gruppo Ospedaliero San Donato Foundation -IRCCS Galeazzi Institute,Via R. Galeazzi 4,Milan, Italye-mail: carlo.romano@grupposandonato.it

E. De Vecchi : L. DragoLaboratorio di Analisi Cliniche e Microbiologia, GruppoOspedaliero San Donato Foundation - IRCCS Galeazzi Institute,Milan, Italy

L. DragoLaboratorio di Analisi Cliniche e Microbiologia,Ospedale Luigi Sacco, Università degli Studi di Milano,Milan, Italy

Eur Orthop Traumatol (2012) 3:177–182DOI 10.1007/s12570-012-0114-x

Methods

Treated textiles

Dressings and drapes were treated with a finishing technol-ogy characterized by a chemical pretreatment specific foreach textile in order to achieve the required activation fol-lowed by a treatment consisting in the binding of the activesubstances (quaternary ammonium salts, aromatic and ali-phatic alcohols and isothiazolone derivates) to reach thefinal concentration of 0.4 % (SANIT®, American LinenSupply Company, ALSCO, Milan, Italy) [8, 9].

In vitro testings

Microorganisms

Determination of the antibacterial effect of textiles was per-formed according to EN ISO 20645 (2004) standard foragar diffusion plate test. S. aureus ATCC 6538 andEscherichia coli ATCC 11229 were used to ensure repro-ducible results.

One strain of methicillin-resistant S. aureus (MRSA),methicillin-resistant Staphylococcus epidermidis (MRSE),Pseudomonas aeruginosa, Streptococcus pyogenes andone of E. coli producers and not a producer of extended-spectrum beta-lactamases were used.

Agar diffusion plate test

Antibacterial textiles were placed on two-layer agar plates.The lower layer free from bacteria was prepared with 10±0.1 ml of blood agar [tryptic soy agar (TSA) with 5 % sheepblood] for S. pyogenes, TSA for S. aureus and E. coli andMuller Hinton for the remaining strains and poured into asterile Petri dish.

The upper layer was prepared by pouring 5.0±0.1 ml ofagar inoculated with 1–5×108 CFU/ml of bacterial workingculture into each Petri dish and left to congeal. Textilesmeasuring 25±5 mm were pressed onto the inoculated agarwith sterilized tweezers. Plates were incubated at 37 °C for18–24 h, except for S. pyogeneswhich was incubated at 37 °Cfor 18 h in 10%CO2-enriched atmosphere. Reproducibility ofthe method was assessed by testing five times for five con-secutive days each microorganism. Antibacterial activity andinhibition zone were determined according to EN ISO 20645instruction. In particular, an inhibition zone >0 mm with nogrowth under the specimen was considered as index of goodeffect of the antibacterial treatment, whilst a 0-mm inhibitionzone and a slight growth in the medium under the specimenindicated a limited activity. An insufficient effect was repre-sented by 0 mm inhibition zone and a moderate/heavy growthin the medium.

In vivo testings

Evaluation of contamination rate of untreated white coats

Preliminary evaluation of contamination rates of white coatswas performed before testing treated textiles. Samples weretaken from white coats on the first and seventh day of usefrom the right and left sides of chest, cuffs and pockets bypressing a 30-cm2 contact plate (Envirocheck® Contactplates, VWR International, Milan, Italy) on the selectedareas for 20 s. Contact plates contained TSA and neutral-isers (0.07 % lecithin, 0.5 % polysorbate 80, 0.05 % histi-dine and 0.05 % thiosulphate), which had been previouslytested for their ability to neutralize the specific combinationof the active antibacterial substances present on treatedwhite coats.

Comparison of microbial contamination of treatedand untreated white coats

A double-blind randomised study was conducted betweenMarch 2010 and June 2010 at our Institute. Ten physiciansand ten surgeons were enrolled into the study. Ten treatedand ten untreated reusable white coats made of 60 % cottonand 40 % polyester and labelled A and B were provided byALSCO. Untreated white gowns were used as controls. Arandomisation list created by the producer was opened at theend of the study, while during the study, both physicians andpersonnel of the laboratory were blinded as far as treatmentwas concerned.

All involved physicians were committed to perform dailyactivities in the orthopaedic ward, including medications atthe patient’s bed, clinical examinations and ambulatoryvisits. Every physician wore a treated coat for seven con-secutive days and then an untreated coat for another7 days, in accordance to the randomisation list, so that bythe end of the study all ten physicians had worn both A and Btextiles. Chest, cuffs and pockets (right and left sides) weresampled before and after 7 days of use, as previously de-scribed (Fig. 1).

Comparison of microbial contamination of treatedand untreated surgical gowns and drapes

Antimicrobial properties of treated surgical gowns anddrapes were evaluated in a double-blind randomised assayversus control textiles. Ten surgeons received two surgicalgowns (labelled A and B) to wear in two consecutive sur-geries. In addition, two sets (labelled A and B) containingfour surgical drapes were used at each surgery and placedonto three instrument tables and one on the patients’ inter-vention site (knee or hip joint replacement). Surgical textileswere made of conductive fibers and polyester trilaminate.

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Randomisation lists were prepared at the beginning of thestudy by the manufacturer and opened after its end.

After each intervention, eight samples were collectedfrom the surgical gowns: cuffs, forearms, chest and abdo-men (right and left sides) as previously described. Sampleswere taken from the drapes placed onto the patient at the

surgical site and at a distance of 20, 40 and 60 cm and fromthree instrument tables (1, 2 and 3).

Culturing technique

Contact plates were incubated aerobically at 37 °C for 48 hand at room temperatures for further 48 h. Total colony countswere performed after 48 and 96 h. Each colony, after Gram’sstaining and morphological analysis, was further isolated onthe appropriate media. Gram-positive strains were tested forcatalase and coagulase reactions. Coagulase-positive isolateswere further identified by API staph system (bioMérieuxMarcy l’Etoile, France). Gram-negative strains were isolatedand identified by API 20NE or API 20E (bioMérieux,) on thebasis of oxidase reaction.

Staphylococci isolates were assessed for susceptibility tooxacillin by using the Kirby-Bauer disc diffusion method.All media were purchased from Biolife (Milan, Italy).

Statistical methods

Statistical analysis was conducted with the Mann–WhitneyU test for nonparametric data. Statistical significance wasconsidered as P<0.05.

Results

In vitro testings

According to EN ISO 20645 test method’s evaluation,treated textiles showed a good effect against S. aureusATCC 6538 and E. coli ATCC 11229. Activity oftreated textiles was considered effective against MRSAand MRSE clinical isolates with inhibition of growth ofat least 1 mm (Fig. 2). A good effect was also obtainedagainst E. coli and S. pyogenes strains with no growthin the nutrient medium under the specimen and 0 mminhibition zone, whilst an insufficient effect was ob-served against P. aeruginosa isolate, which showed amoderate growth in the medium.

Fig. 1 Site of plating for cultural examination (green circles) of whitecoats

Fig. 2 In vitro testing ofgrowth inhibition of treatedtextile (T), compared to theuntreated control (C), of anosocomial strain of,respectively, an MRSA (left)and MRSE strain

Eur Orthop Traumatol (2012) 3:177–182 179

In vivo testings

Microbial contamination

The most frequently isolated microorganisms from routinelyused white coats are summarized in Table 1. More than90 % of bacteria were Gram positive, with a predominanceof coagulase-negative staphylococci (74 %) and S. aureus(20 %). Four percent of S. aureus isolates were methicillin-resistant. Bacillus spp. (3 %) and Sarcina spp. (2 %) wereisolated at a lower extent. Acinectobacter spp. represented0.2 % of all microorganisms isolated.

Comparison of microbial contamination of treatedand untreated white coats, surgical gowns and drapes

Bacterial contamination of finished textiles resulted statisti-cally lower in all the investigated regions, when compared tountreated textiles (Table 2). In particular, bacterial contamina-tion of treated white coats after 7 days of use was more thanfivefold lower than that of untreated textiles. The chestshowed the lowest bacterial load in both treated and untreatedwhite coats; the left side resulted in a higher average bacterialcount, although this difference was not statistically significantin either location, both in treated and untreated coats, excep-tion made for the cuff of the untreated garments (P<0.05).

Results obtained from all surgical gowns showed thattreated textiles presented a lower amount of bacteria thanuntreated textiles at all sites (Table 3). The most contami-nated area in both treated and untreated surgical gowns wasthe abdomen followed by cuffs and forearms.

Treated drapes from the patient’s intervention site andfrom the three instrument tables resulted to have a lowernumber of bacteria than untreated drapes (Table 3). On theaverage, bacterial load was higher at 60 cm from thepatient’s wound than at 20 or 40 cm.

Discussion

The main findings of this study are that hospital textiles,both in wards and in the operatory rooms, become colonized

from bacteria after their common use and that the coloniza-tion rate may be significantly reduced by a suitable antibac-terial finishing of textiles. The present study confirms thehigh prevalence of Gram-positive bacteria, particularlycoagulase-negative staphylococci, as the leading contami-nant bacteria of hospital textiles [7, 10]. Moreover, ourfindings showed the occurrence of methicillin-resistantstrains isolated from the tested dressings.

Cuffs and pockets of white coats have been shown to bethe most highly contaminated areas, as shown in otherstudies [1, 3, 5, 6]. During clinical examination, the whitecoat worn by the physician, specially the forearm and cuffregions, comes frequently into contact with the patient’sclothing and skin possibly increasing the chances of cross-contamination [1, 3, 5, 6].

The left side of the white coats was found, in this study,to be, on the average, more contaminated than the right one,even if the difference was only statistically significant at thecuff region. The difference between the left and right sidewas not observed in surgical gowns. There is no definitiveexplanation of this empirical observation. Seven physiciansout of ten were right handed, and this may be a possiblereason for the different contamination rates of the left andright side; however, comparing pooled data from left- andright-handed physicians, we did not observe a statisticaldifference in the contamination rate (data not shown). An-other possible explanation could be the presence of a pocketonly in the left upper part of the coat, in which pens andpencils are contained, and that may be associated with amore frequent hand touch and passing over.

Despite adherence to standard aseptic surgical techniquesto reduce the incidence of site infections [11, 12], our find-ings indicate that a measurable bacterial contamination wasdetected in all areas of the surgical gowns and drapes by thecompletion of the surgical procedures. Although a relativelylow amount of colonies on the sections between the chestand the surgery table was observed, the risk of transmittingpathogens to the surgical wound remains possible [11, 13].Our findings are in line with those recently reported byBible and co-workers [11] that observed a percentage ofcontaminated surgical gowns and drapes, ranging, at theend of surgery, from 6 to 48 %. Our study adds to thisprevious observation the average and range values of theobserved CFUs and also demonstrates that a certain degreeof contamination is ubiquitous in the surgical field at the endof the surgical procedure. We also proved that bacterialcontamination of the surgical textiles may be significantlyreduced with the use of the tested antimicrobial finishing.

As to concern the possible relationship of the observedcontamination rate in the surgical field and the effective riskof clinical infection, no definitive data are available; while,in fact, a limit of 50–150 CFU/m3 of air has been recom-mended in the surgical room [18], to our knowledge, no

Table 1 Microbial contaminants of untreated white gowns

Microorganisms Total counta %

Coagulase-negative staphylococci 2,758 74

Staphylococcus aureus 746 20

Bacillus spp. 141 3.8

Sarcina spp. 75 2

Acinetobacter spp. 8 0.2

a Number of CFU from all sampled regions of ten white gowns

180 Eur Orthop Traumatol (2012) 3:177–182

standard has been set, until now, as regards the minimumbacterial count on surgical textiles that can be consideredacceptable at the end of a surgical procedure. A quantitativeaerobic colony count of <5 CFU/cm2 on frequent hand touchsurfaces in hospitals has been claimed as the bacteriologicalstandard with which to assess clinical surface hygiene; how-ever, this was not referred to the surgical field that is stillsupposed to remain sterile until the end of surgery [19].

Antibacterial textile production has become increasinglyprominent for hygienic and medical applications, and dif-ferent treatments have been developed in recent years[14–16]. This is, to our knowledge, the first report on theefficacy both in vitro and in the clinical setting of a finishingantibacterial technology to reduce the contamination of hos-pital textiles; considering the ease-of-use for a large-scale

application and the reduced economical impact, this tech-nology may open a new pathway to protect healthcare work-ers and their patients, reducing bacterial spreading ofbacteria in the hospital environment.

However, the following limitations of this study shouldbe considered:

1. The present study provides no evidence as regards theimpact of a large-scale use of antibacterial finishing oftextiles on the incidence of nosocomial or surgical siteinfections in a given hospital. The clinical relevance ofthe use of antibacterial textiles should ideally better beassessed in a prospective (multicenter) study. Nonethe-less, it should be noted, in this regard, that transferringthe observation of a measurable reduction of bacterialcount to a clinical reduction of septic complications isparticularly challenging. In fact, the vast majority of theother tools and behaviors, universally accepted to pre-vent infections in hospitals, like for example surgicalhand antisepsis and scrubbing, still only rely on theobservation of bacterial count reduction and do lackany scientific evidence of reducing surgical site infec-tion rate [17].

2. The relative cost/benefit ratio of the routine implemen-tation of the finishing antibacterial technology or itsmore specialized use (e.g. for operatory rooms, inten-sive care units, septic units, etc.) remains to be assessed,and no definitive conclusions in this regard may bedrawn on the basis of the present research.

3. Antimicrobial textile finishing should be regarded as afurther measure to reduce bacterial colonization and notintended to replace existing hygiene behaviors, like, forexample, hand disinfection and/or protection withgloves or the use of single-use gown when workingclose to highly contaminated patients. Antimicrobialtextiles should also not be regarded as a reason foravoiding training and education of personnel to othermeasures of infection control.

4. This study does not provide data concerning the comfortor long-term possible adverse reactions due to the rou-tine use of the finished antibacterial textiles.

Table 2 Comparison betweentreated and untreated white coats

R right, L left, M-W U testMann–Whitney U testaStatistically significant

Site Total colony count mean CFU/30 cm2(range) P value (M–W U test)

Treated (n010) Control (n010)

Chest R 45 (5–81) 213 (40–360) 0.03a

Chest L 66 (10–130) 296 (75–400) 0.02a

Cuff R 75 (25–140) 452 (90–780) 0.01a

Cuff L 133 (61–200) 1,006 (155–1,600) 0.01a

Pocket R 132 (57–184) 596 (115–900) 0.03a

Pocket L 217 (100–400) 896 (390–1275) 0.01a

Table 3 Bacterial contamination of treated and untreated surgicaltextiles

Sites tested Treated (n010) Control (n010) P (M-W U test)Mean CFUs/30 cm2 (range)

Surgical gowns

Chest R 1 (1–5) 14 (3–26) 0.02a

Chest L 2 (1–7) 16 (3–33) 0.03a

Cuff R 3 (2–5) 20 (4–44) 0.03a

Cuff L 5 (3–8) 18 (5–36) 0.03a

Forearm R 3 (1–7) 17 (5–25) 0.02a

Forearm L 1 (0–3) 18 (2–29) 0.03a

Abdomen R 5 (1–10) 20 (8–30) 0.03a

Abdomen L 6 (1–10) 22 (7–35) 0.02a

Drapes

20 cm 8 (5–10) 15 (10–18) 0.01a

40 cm 6 (4–8) 19 (7–27) 0.02a

60 cm 12 (10–15) 27 (15–32) 0.01a

Instrument table 1 3 (2–5) 23 (3–36) 0.04a

Instrument table 2 7 (5–10) 24 (10–35) 0.01a

Instrument table 3 2 (0–6) 16 (5–25) 0.02a

R right, L left, M-W U test Mann–Whitney U testa Statistically significant

Eur Orthop Traumatol (2012) 3:177–182 181

Acknowledgments This study was partially supported by the ItalianMinistry of Health and is part of an ongoing research under the“AMICROTEX Project”, co-financed through POR FESR 2007–2013 (European funds for regional development) 13587782 cupE7I0000090007-ATP Competition 2009, by the European Union, theItalian Government and the Region of Lombardy, in accordance withCommission Regulation (EC) 1828/2006, Council Regulation (EC)1083/2006 and the rules set forth by the Region of Lombardy.

Conflict of interest The authors declare that they have no conflict ofinterest.

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