Decontamination of stainless-steel bowls with 80% (w/v) alcohol for 30 s and 60 s: randomized experimental study

Objective: to compare the efficacy of 80% (w/v) alcohol, rubbed for 30 and 60 seconds, in the manual processing of stainless-steel wash bowls, after cleaning with running water and neutral detergent. Method: experimental study conducted in a hospital in the state of São Paulo, Brazil, on 50 bowls randomly divided into two groups of 25 bowls each for interventions of 30 and 60 seconds of rubbing with 80% (w/v) alcohol. Results: based on the microbiological analyses collected, before and after the interventions for both groups, partial efficacy of the disinfectant was observed even when extending rubbing time. In both groups, there was a higher prevalence of survival of Pseudomonas aeruginosa, with 14 strains that were resistant to carbapenems, being, specifically, 11 to imipenem and three to meropenem. Conclusion: stainless-steel bed wash bowls decontaminated for reuse by 80% (w/v) alcohol, after cleaning with running water and neutral detergent, showed to be reservoirs of hospital pathogens. The use of bed wash bowls for patients with intact skin would not have worrying consequences, but considering those with non-intact skin and the contamination of professionals’ hands, the results in this study justify the search for other decontamination methods or the adoption of disposable bed baths.


Introduction
Stainless-steel bowls are processable health products (HPs) used in health care services for, among other purposes, the hygiene of bedridden patients. Although automated cleaning and disinfection of these items, using flushing thermal washer-disinfectors is not only more practical, but safer from the point of view of cross-and occupational contamination (1)(2) , manual decontamination by cleaning with running water and neutral detergent, followed by rubbing with 70% (w/v) alcohol disinfectant, for 30 seconds (30 s), is still a frequent method in our country (3) .
Such manual decontamination procedure is based on the bactericidal efficacy of alcohol in various concentrations, and it is concluded that the 30-second exposure time at a concentration of 70% (w/v) is sufficient to eliminate microorganisms (4) . Furthermore, wash bowls are considered non-critical items, according to the contamination potential classification (5) , which, a priori, considers them to be HPs that come into indirect contact with patients' skin, thus justifying that the usual practice of cleaning and disinfecting them manually with 70% (w/v) alcohol for 30 s is an acceptable procedure as an alternative to automated cleaning and thermal disinfection methods (6) .
However, in hospitals, these bowls are commonly used to assist patients of high care complexity, with unhealthy skin and/or colonized intact mucous membranes, which would theoretically have an indication of more stringent procedures than those recommended for non-critical HPs, that is, cleaning followed by lowlevel disinfection (6) , justified by their reclassification as semi-critical HPs.
Among the chemical disinfectants currently available, ethyl or isopropyl alcohol is widely used in Brazil and in the world, due to its favorable characteristics, such as low cost and quick and easy access, being, therefore, recommended for procedures for disinfecting inanimate surfaces. One of the pioneering publications recommends the use of alcohol in concentrations of 70 to 90% (w/v) in an exposure time ≥ 60 s (4) . These concentration and time parameters -critical points for disinfectionare not consensual in publications, and the minimum concentration of 60% (w/v) (7) and contact time from 30 s to 90 s are also indicated (7)(8) .
A systematic review on the disinfection of semicritical products using 70% (w/v) alcohol, or in approximate concentrations, points out that such a disinfectant cannot be recommended unrestrictedly for all HPs. However, according to the type of semi-critical material, disinfection can be achieved with and without prior cleaning (8) . Although this review did not include an assessment for HPs classified as non-critical, it deductively applies to bowls used in the hygiene care of bedridden patients, as it is less critical.
This investigation is justified considering that, to this date, there is not a single and definitive answer about the safety of alcohol use in the manual decontamination of bowls used in bedridden patients' body hygiene. Additionally, there is nurses' technical responsibility to control patients' cross-contamination by HPs, especially the dissemination of drug-resistant or multidrug-resistant microorganisms. It is noteworthy that bowls are often used for the hygiene of bedridden patients with broken skin as well as for elderly patients who are highly dependent on nursing care to meet their basic human needs, many of whom have undergone or are undergoing invasive procedures (surgeries, catheters) and/or have wounds and infectious processes.
That said, we ask: How efficacious is manual decontamination in the reuse of stainless-steel bowls for bathing bedridden patients by rubbing 80% (w/v) alcohol for 30 s, having previously cleaned them with running water and neutral detergent? Is there a difference in the efficacy of decontamination in increased contact time of 60 s? As a hypothesis, it was assumed that doubling the 80% (w/v) alcohol contact time would increase the efficacy of the decontamination procedure on these bowls.
In order to answer our questions and test the hypothesis, the following objectives were outlined: • General: to compare the efficacy of manual decontamination in the reuse of stainless-steel wash bowls by rubbing them with 80% (w/v) alcohol for 30 s and 60 s, after cleaning with running water and neutral detergent; • Specific: if results indicate the survival of microorganisms, to identify the hospital bacteria isolated after the bowl decontamination procedure, as well as their susceptibility to antimicrobials, compared to previous contamination before decontamination.

Method Design
Randomized experimental single-blinded study, with a before-after design (9) , conducted in a single center, according to the Standards for QUality Improvement Reporting Excellence -SQUIRE 2.0 (10) .

Site and sample
The study was conducted in a large public hospital with 417 operational beds in the state of São Paulo, from 01/02 to 05/31/2018, on stainless-steel wash bowls used in an inpatient internal-medicine clinic with From these data, a sample with 80% power and 95% reliability was designed, consisting of 50 bowls randomly distributed equally in two groups, as shown in Figure 1, using a paired-proportion test (two moments) and microbiological tests before and after the proposed interventions for each group.

Criteria for inclusion, allocation and sample follow-up and analysis
Six bowls used for bed baths at the hospitalization unit were followed-up. All of them were made of stainless steel and had no visible damages, such as dents or grooves.
The bowls were identified alphanumerically, using the initials of the hospitalization unit and the utensil number, for example: CM-1, CM-2, ..., CM-6. Afterwards, they were cleaned with running water and neutral detergent, which was followed by disinfection and storage, according to the procedure used at the institution, that is, the bowls were entirely rubbed with 80% (w/v) for 30 s, according to the protocol for inclusion, allocation and sample follow-up and analysis ( Figure 1).
Before beginning data collection, a pilot test was carried out on two bowls, one from each follow-up group, which showed no need for readjustment of the procedural steps of the protocol, including those related to laboratory analyses. Thus, those bowls were included in the sample and designated in the results as "sample 1" (Figure 3) and "sample 2" (Figure 4).
One of the researchers conducted all the datacollection phases, from the randomization process to sample collection before and after cleaning, followed by disinfection, counting on an assistant for support during collections and always in the presence of an observant referee, who followed and strictly verified compliance with all the steps provided for by the protocol in hand, using a form.
The random selection of bowls, that of the patients who would be bathed as well as that of the allocation groups for the 30-s and 60-s procedures were carried out daily, using card draw techniques, in which the cards were duly identified in three brown-paper envelopes, named as follows: the first, "beds", with the number of beds of bedridden patients with a prescribed bath; the second, "bowls", with six cards numbered from 1 to 6; the third, related to the "allocation group", with two cards, one for the time of 30 s and the other for 60 s.
An individual who was unrelated to the study drew the cards from the respective envelopes: "bowl", "bed" and "allocation group" in the follow-up. If the bowl was not available for reuse, or if the bed was empty, a new card was drawn, and the data collection protocol was followed, as described: (1) researcher -distribute the drawn bowls to the nursing technicians responsible for providing the bed bath to the respective patient, instructing them, to hand the bowls over to the researcher after the procedure is finished, still containing the bath water, to dispose of it in the utility room and, subsequently, collect the first sample for microbiological culture; (2) researcher -proceed to hand washing and put on sterile gloves to receive the bowl; Rev. Latino-Am. Enfermagem 2021;29:e3475. for 24 to 48 h, in order to isolate and identify hospital microorganisms.
Colonies from different culture media were identified by conventional phenotypic tests (11) .
The Antimicrobial Susceptibility Test (AST) by agar disc-diffusion (12) was used to evaluate the profile of bacteria isolated from wash bowls, and the reading was

Results
The analyses showed homogeneity in the random allocation of stainless-steel wash bowls in the followup strata, 30-s and 60-s groups, as they did not show statistically significant differences between the variables related to the clinical characteristics of bowl users and, consequently, to their classification, according to the degree of risk for infection after use (5) .       microorganisms, time and temperature of exposure, concentration and potency, as well as chemical and physical factors, organic and inorganic matter and biofim (7) and, certainly, these factors justify the divergent results in studies and in the clinic practice involving alcohol.
The results in this study show scientific evidence that stainless-steel wash bowls are playing a role as fomites in the spread of strains of hospital microorganism strains that are resistant to antimicrobials, when processed with 80% (w/v) ethyl alcohol, even when it is rubbed according to recommended concentrations and periods of time (4) .
Ethyl or isopropyl alcohol has been indicated for intermediate and low-level disinfections, on smooth and hard surfaces, with a minimum exposure time of 60 s (4,7) , in concentrations between 70 and 90% (4) , the minimum concentration found in the literature being 60% (w/v) (7) .
In Brazil, bed-bath bowls are stainless and reused, and they usually undergo a decontamination procedure of 30-s rubbing with 70% (w/v) ethyl alcohol, after previous cleaning with running water and neutral detergent, followed by drying (3) . Such time of exposure to ethyl alcohol is based on experimental research on suspended microorganisms, published in the 1980s (4) and ratified by several studies.
The universal recommendation to clean one's hands with 70% (w/v) alcohol also testifies to the belief in the efficient microbicidal action of alcohol in this concentration (18)(19) . transmission is cross-linked and non-environmental (20) (14) .
Regarding biofilm, the fact is that these microorganisms have great capacity to form it. A study on 45 bacterium strains isolated from cockroaches captured in hospitals showed the capacity of biofilm formation by all strains, on which the bactericidal effect of alcohol decreased to 60% in the case of adherent bacteria, when compared to 100% effect on free cells (15) . Additionally, from the literature review, it was assumed that the residual action of alcohol disinfection itself contributes to increase the formation of biofilm produced by P. aeruginosa, more specifically on Psl and Pel synthesis, considered to be exopolysaccharides from such bacterium (16)(17) . This may explain the fact that the bacterium appeared only in the microbiological analysis performed after the disinfection procedure, in the hypothesis that the bowls analyzed had biofilm. ( Figures 3 and 4). This finding reinforces the importance of using standard precautionary principles by those who will perform decontamination. It is known that, in some service routines, this responsibility is delegated to workers without health care training, such as those who work in the hospital cleaning service.
The efficacy of a chemical disinfectant is multifactorial, involving determining factors for microbicidal action, such as: number, location and innate resistance of Rev. Latino-Am. Enfermagem 2021;29:e3475.
with unhealthy skin or with invasive devices, such as catheters and probes and, therefore, requiring high-level disinfection. A relatively simple and practical measure is the replacement of the conventional bed-bathing technique for disposable methods (3) , in this case weighting issues regarding costs and environmental sustainability.
As a limitation to this study, the fact that a control group was not created, so as to compare with disinfection efficacy by thermal disinfectors, was considered.
Finally, the authors understand that one of the contributions from this study is the fact that alcohol efficacy as a disinfectant cannot be considered in an uncritical way.

Conclusion
There was not total elimination of vegetative bacteria from the bed-bath wash bowls decontaminated by cleaning with running water and neutral detergent, followed by rubbing with 80% (w/v) alcohol for 30 s and 60 s, with predominant recovery of Pseudomonas aeruginosa, including those resistant to antimicrobials, which refuted the initial hypothesis in the study.