The use of antimicrobial-impregnated fabrics in health services: an integrative review

Objective: to analyze evidence concerning the feasibility of antimicrobial-impregnated fabrics in preventing and controlling microbial transmission in health services. Method: an integrative review using the following databases: MEDLINE (via PubMed), Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Scopus, and Latin American and Caribbean Health Sciences Literature (LILACS), regardless of language and date of publication. Seven studies were included in the analysis to verify the types of fabrics and substances used to impregnate the fabrics, applicability in health services, and decrease in microbial load. Results: silver nanoparticles and copper oxide are the main antimicrobial substances used to impregnate the fabrics. The patients’ use of these fabrics, such as in bed and bath linens and clothing, was more effective in reducing antimicrobial load than in health workers’ uniforms. Conclusion: the use of these antimicrobial-impregnated textiles, especially by patients, is a viable alternative to prevent and control microbial transmission in health services. Implementing these fabrics in health workers’ uniforms requires further studies, however, to verify its effectiveness in decreasing microbial load in clinical practice.


Introduction
Healthcare-Associated Infections (HAIs) account for increased morbidity and mortality, lengthier hospitalizations, increased healthcare costs, and favor the selection and dissemination of multi-drug resistant microorganisms (1) . In this sense, it is essential to pay attention to the various fabrics used in healthcare settings, considering that both fabrics worn by workers, such as in coats and uniforms, and those used by patients like in bed and bath linens and gowns play an essential role in microbial contamination and transmission (2) .
Coats are widely worn at all healthcare levels as a barrier to protect workers against exposure to body fluids and infectious agents; their protective role against microbial contamination is often overestimated though (3)(4) .
Hence, attention should be paid to the possibility of coats and clothing being contaminated, especially when hand hygiene is neglected, considering that hand hygiene is vital to break the chain of microbial transmission (5)(6) .
Another aspect to be considered refers to how frequently coats are washed. Results reported by a systematic review show that from 5% to 65% of the health workers wash their coats only once every two weeks. This situation is even more critical among health care students, who report washing coats every three weeks and a half (7) . This fact is of concern because the low frequency at which coats are sanitized may promote microbial proliferation and transmission. Thus, unwashed coats worn in health services are more likely to take part in the chain of infection.
In addition to coats, the fabrics used by patients in health services represent an important threat as a source of microbial cross-contamination and transmission (2) . This motivates industries to invest in technology to implement alternative resources and options with antimicrobial properties (8)(9) .
Fabrics with enhanced functionality are currently available for a wide range of applications. They are of great interest in the healthcare field due to their ability to prevent or inhibit the growth of microorganisms, inhibit the formation of biofilms, or impede microbial propagation, thus removing sources of infection (10)(11) .
Note, however, that there is a gap between scientific knowledge concerning the use of these different fabrics in healthcare services, their potential or ineffectiveness to decrease microbial contamination, and their association with potential applicability.  (12) . This virus can spread through respiratory droplets (13) that contaminate surfaces, including fabrics.
The viability of the SARS-CoV-2 varies according to the characteristics of surfaces, while viral loads are undetectable on the second day of contact with textile surfaces (14) . Therefore, patients' gowns and health workers' uniforms are vehicles that transmit SARS-CoV-2 (15) , even if for a relatively short period.
The United States of America, the current epicenter of the COVID-19 pandemic, has recorded 120,467 cases of infection among health workers (16) , despite recommendations to expand diagnostic tests (17) .
Even though we cannot assume the real factors leading to these epidemiological data, the use of textiles impregnated with antimicrobial substances in healthcare services can turn SARS-CoV-2 ineffective, and consequently, promote the biological protection necessary for workers and patients.
Given the previous discussion, this study's objective was to analyze evidence concerning the viability of fabrics impregnated with antimicrobial substances in preventing and controlling microbial transmission in health services.

Method
This is an integrative review, characterized by the ability to group and synthesize relevant scientific evidence regarding a specific topic or guiding question, contributing to understanding knowledge deeper and better by providing a portray of the literature at a given time (18) .
This study was conducted in five stages, namely: the establishment of a clear and objective question based on the identification of a problem; search for primary scientific studies; assessment of studies according to previously established inclusion and exclusion criteria; critical analysis; characterization of the studies selected to compose the review; and presentation (18) .
Hence, the following question was established: Therefore, two researchers with expertise in the field selected the studies to compose this review's final sample.
The studies were assessed in two stages: assessment of titles and abstracts and assessment of the full texts. Each researcher independently conducted both stages. After the researchers finished the assessments, they met to discuss and reach a consensus regarding the inclusion and exclusion criteria used to select the studies. A third researcher would mediate potential disagreements, but this was not necessary.
In total, 120 duplicated studies were excluded, and the titles and abstracts of 165 studies were analyzed, regardless of language or date of publication, to verify whether they answered the guiding question. In this stage, the sample was reduced to 76 studies. Another 69 studies were excluded after the full texts were read either because they did not address health services; that is, fabrics impregnated with antimicrobial substances were not used by patients or health workers, or the authors did not specify whether the enhanced fabrics were designated to health services. Hence, the final sample included seven studies.
To avoid methodological biases, two researchers analyzed and characterized the selected studies. Hence, the studies were carefully read, and data considered relevant to answer the guiding question were extracted.
A form was specifically developed to guide this process and addressed: identification (reference), method, types of impregnated fabrics, types of substances used, specific applicability/use of the fabrics in health services, main results, limitations, and quality of evidence.
The quality of evidence reported by the studies included in this review was classified into high, moderate, low, or very low, according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) (20) .

Results
The search in the scientific literature for conclusive answers to the question regarding the feasibility of using    (21) Seven-month crossover, doubleblind, controlled intervention (two three-month periods separated by one month for washout period) with chronic patients dependent on mechanical ventilation hospitalized in two wards of a long-stay care hospital. In the 1 st period, one ward received the copper oxideimpregnated fabrics while the other ward received the control fabrics. In the 2 nd period, the ward that first received the impregnated fabrics received the control fabrics and vice-versa. The results were analyzed by comparing the periods, fever days, the beginning of the antibiotics treatment, and daily dose. -Polyester.
-Copper oxide at 1%. -Textile used by patients: towels and clothing.
The study shows that the use of copper oxideimpregnated textiles used in long-stay hospitals decreased HAI s* indicators (by 55.5% on days the patients had a fever, 29.3% at the beginning of the antibiotics treatment, 23% on days of treatment, and 27.5% on daily dose) when compared to the period when control fabrics were used.
-Study conducted in only two wards of a single facility; -It was not possible to determine the effect of the intervention on specific HAI s* . Moderate.
(2017) (22) In vitro controlled study, in which a coating, composed of silver nanoparticles embedded in a silica matrix, was deposited by radiofrequency co-sputtering on cotton-fabric designated for surgical gowns. The antimicrobial properties of the samples of coated fabrics and control fabrics (uncoated) were assessed using the inhibition halo test against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria and against yeast (Candida albicans). Additionally, the treated fabric was characterized in terms of its physical properties and functional performance. -Cotton.
-Silver nanoparticles embedded in silica matrix.
-Surgical scrubs.  (24) Controlled in vitro study comparing antimicrobial activity in cotton fabrics impregnated with silver and untreated cotton fabrics (control) 2, 4, and 24 hours after the fabrics had been exposed to the following microorganisms: Controlled, quasi-experimental intervention study, conducted during the replacement of an old clinical wing by a new one in an acute care hospital. The study lasted 25.5 months, divided into baseline (before the old wing was replaced with a duration of 12 months) and assessment (after the old wing was replaced with a duration of 10 months).
There was an interval between the two periods to implement the surfaces and fabrics impregnated with copper oxide in the new hospital wing wards. During the assessment period, the patients hospitalized in an unmodified hospital wing and the new hospital wing were assessed. The incidence of HAIs * was compared between both periods.
-The type of textile used is not described.
-  (27) Intervention study conducted with an ambulance staff for four weeks. During the 1 st and 3 rd weeks, employees wore conventional uniforms, and in the 2 nd and 4 th weeks, they wore silver impregnated-uniforms. The uniforms were washed before the beginning of each assessment week. Samples of jackets and pants were collected before the first shifts and on the 3 rd and 7 th days after the uniforms were removed, to assess the bacterial load.
-The textile used was not described. -Silver.
-Uniforms worn by emergency care workers: jacket and pants The bacterial load verified in the silver-impregnated jackets was 3.8 and 2.3 times higher on the 3 rd and 7 th days, respectively, compared to the regular jackets. Additionally, the bacterial load found in the silver impregnated-pants almost doubled on the 3 rd days, though it was lower on the 7 th days, compared to the regular pants. That is, the silver-impregnated uniforms did not decrease the bacterial load. Three of the studies selected (A1, A5, and A6) report that copper oxide-impregnated fabrics, mainly bed linens and clothing worn by patients, are efficient in decreasing the microbial load, contributing to a decreased occurrence of HAIs (21,(25)(26) . The potential mechanisms of the copper oxide's antimicrobial activity include oxidative  reporting that the intervention with fabrics impregnated with antimicrobial agents, especially copper oxide, was responsible for decreased HAIs (21,(25)(26) , with potential to influence changes in clinical practice. This type of intervention may be responsible for decreasing microbial contamination; however, one cannot affirm that it was responsible for decreasing HAIs, considering that there are other variables directly or indirectly linked to the development of infections (29)(30) .
Silver nanoparticles, in turn, are widely used in the manufacturing of textiles with antimicrobial properties.
According to the results reported by one in vitro study using different bacterial strains, the silver nanoparticles' antimicrobial action occurs through oxidative stress, which causes damage to the microorganism DNA (31) .
Among the studies included in this integrative review, four (A2, A3, A4, A7) addressed the impregnation of textiles with silver nanoparticles (22)(23)(24)27) while the efficacy of the antimicrobial agents (22,24) was only reported in the two in vitro analyses (A2, A4). The two remaining studies (A3, A7), in which silver-impregnated textiles were used in the uniforms of health workers during care delivery, report no differences regarding decreased microbial contamination in comparison to conventional fabrics (23,27) .
Note, however, that the sample size of one of these studies (A7) was small and may not be representative for final analysis (27) . Therefore, only one study (A3) reported the antimicrobial ineffectiveness of textiles impregnated with silver nanoparticles used in health services (23) , suggesting the need for further studies to support conclusions.
The contextualization of these findings to the context of the COVID-19 pandemic needs to consider that the transmission of the SARS-CoV-2 mainly occurs via direct contact (between contaminated hands and mucosa) and via droplets released by contaminated individuals when speaking, coughing, or sneezing (13) . Droplets, and also aerosols (32)(33) , can contaminate surfaces and fomites so that the clothing of health workers is an essential tool to promote biosafety and the quality of health care delivery (34)(35) .
Nonetheless, the risk of contamination and infection is enhanced when inappropriately dressing and removing the PPE. This is of concern, considering that a study verified, through a clinical simulation of COVID-19-related cases, mistakes of health workers when dressing and removing the PPE (36) .  (37) .
In this sense, as reported by the study using polycotton fabric (composed of polyester and cotton) impregnated with silver nanoparticles, positive results were obtained in only two minutes 99% of the times when SARS-CoV-2 was reapplied to the textile surface (38) .
Thus, the use of fabrics impregnated with antimicrobial substances may be an alternative to prevent infection by this virus when present on textile surfaces used by health workers and patients to minimize infection, contamination, and finally control its outbreak.
Furthermore, given the current COVID-19 pandemic, health workers need to wear PPEs for prolonged periods when providing care, especially among patients infected by SARS-CoV-2. PPEs can lead to adverse skin reactions due to increased heat and sweat. One of the studies reported dry skin, itching, rash, and hives (39) . Therefore, in addition to inhibiting the propagation of the SARS-CoV-2, textiles impregnated with silver nanoparticles are promising as they do not favor the occurrence of adverse reactions, photosensitization, or photo-irritation on the skin (38) .
We acknowledge that certain substances with antimicrobial properties, which are used to impregnate textiles, may cause side effects in the short or long term, due to direct contact with skin, for instance: allergies, changes in the microbiota, and toxicity (40)(41) . Thus, this study's findings include the implications of using potentially toxic substances to impregnate textiles, as there is a possibility that these be harmful to health when in contact with the skin. This analysis is necessary to determine risk-benefits, especially in the long term, considering the implementation of these textiles in health services.
Another aspect that should be taken into account is that technological resources intended to prevent microbial and SARS-CoV-2 contamination depend on health workers being aware of and implementing undoubtedly effective strategies that promote biosafety in health care settings.
These include hand hygiene (5)(6) , surface disinfection, proper handling of materials and equipment used in health care delivery, and PPEs, among other asepsis and antisepsis measures (29)(30) .
As for the applicability of textiles impregnated with antimicrobial agents, there is great versatility, considering Rev. Latino-Am. Enfermagem 2021;29:e3416.
that these fabrics can be used in clothing/uniforms, bed and bath linens, and even in the packaging of surgical materials.
Nonetheless, there is still a need to consider that there are no studies addressing fabrics impregnated with antimicrobial agents designated to manufacture coats.
One of the in vitro studies confirms the need for further studies addressing this topic, in which the authors report that coats manufactured with polyester do not present a physical barrier against fluids and bacteria (42) . These results are of concern, considering that this piece of PPE is widely used at all levels of health care delivery, although it does not seem to provide proper protection to workers.
This study presents important methodological

Conclusion
The use of fabrics impregnated with antimicrobial substances, especially by patients, is a viable alternative to prevent and control microbial transmission in health services. The use of these fabrics in the manufacturing of health workers' uniforms, however, requires further investigation to verify their effectiveness in decreasing the microbial load in clinical practice.