Manual Friction with Ethyl Alcohol at 70% (w/v) to Disinfect Three-Way Stopcocks
, Adriano Menis Ferreira 1,4, Paula Regina de Souza Hermann 1,5, Denise de Andrade 1 and Evandro Watanabe 1,3,*Round 1
Reviewer 1 Report
Dear Authors,
Your paper entitled "Manual friction with ethyl alcohol at 70% (w/v) to disinfect three-way stopcocks" addresses an important topic in medical care. The results would be interesting and useful, yet I have some observations to make.
In Abstract section:
-line 19- please consider replacing "solution" with "alcohol"
In Introduction section:
-some of the information presented in the Discussion section about the microorganisms that can produce contamination of such devices should be moved to this section, to justify why those used in the present study were chosen
-the null hypothesis is not correctly formulated. It should consider the presence/absence of differences between the use and not use of alcoholic solution.
In Materials and Methods section:
-the phrase between lines 76 and 80 needs reformulation as it is grammatically incorrect
-a clearer presentation of the study groups is necessary
In Results section:
-as resulted from Table 1, in the control group the same results were obtained as in the group with the alcoholic solution, which means that alcoholic solution is useless
-the same reason makes the results have no clinical significance
-a post-hoc test would be necessary to show between which groups the statistically significant differences appeared
-the final paragraph of this section - lines 185-187: the values discussed cannot be found in the two tables. Please correct this
In Discussion section:
-lines 196-197: the null hypothesis was rejected, by the results, but the same results were obtained with the control group. The question is asked: why was a control group used, if the results were not compared with it?
-lines 202-203: please reformulate the phrase "All external surfaces, 40% of lumens, and 86.7% of dressing presented bacterial growth", as it gives the impression that these results are obtained from the present study
-comments should be added on the fact that similar results were obtained in the study group with alcohol and the control group
-study limitations are not presented - please add
Author Response
Comments and Suggestions for Authors
Author's Reply to the Review Report (Reviewer 1)
Dear Authors,
Your paper entitled "Manual friction with ethyl alcohol at 70% (w/v) to disinfect three-way stopcocks" addresses an important topic in medical care. The results would be interesting and useful, yet I have some observations to make.
In Abstract section:
Point 1: line 19 - please consider replacing "solution" with "alcohol".
Response 1: The authors of the manuscript agree with the reviewer's consideration and the "solution" was replaced by "alcohol".
In Introduction section:
Point 2: some of the information presented in the Discussion section about the microorganisms that can produce contamination of such devices should be moved to this section, to justify why those used in the present study were chosen.
Response 2: The authors of the manuscript agree with the reviewer's consideration and information about bacteria was moved from the discussion to the introduction in order to justify their use in the present study.
Point 3: the null hypothesis is not correctly formulated. It should consider the presence/absence of differences between the use and not use of alcoholic solution.
Response 3: The authors of the manuscript agree with the reviewer's consideration and the null hypothesis was changed to:
“The null hypothesis tested was that the ethyl alcohol at 70% (w/v) would not have any antibacterial activity and dispersion into the 3-WS lumens when compared to the control group without alcohol.”.
In Materials and Methods section:
Point 4: the phrase between lines 76 and 80 needs reformulation as it is grammatically incorrect.
Response 4: The authors of the manuscript agree with the reviewer's consideration and the sentence was reformulated to:
“A total of 108 3-WS Luer Slip model from Solidor® (Osasco, Sāo Paulo, BR) was intentionally and separately contaminated with Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853) to simulate a real patient healthcare situation with an external bacterial contamination resulting from a failure in the basic principles of asepsis and/or improper manipulation of the device.”.
Point 5: a clearer presentation of the study groups is necessary.
Response 5: The authors of the manuscript agree with the reviewer's consideration and the presentation of the study groups was modified and made clearer to:
“It is worth noting that in this study three experimental groups were created for microbiological analysis:
I) Intervention group: the manual friction of the Female Luer extremity of the 3-WS samples was performed through two steady, unidirectional 360° movements lasting between 5 and 15s with sachets moistened with ethyl alcohol at 70% (w/v) - (Rialcool®, São José do Rio Preto, SP, BR);
II) Control group A: the manual friction of the Female Luer extremity of the 3-WS samples was performed through two steady, unidirectional 360° movements lasting between 5 and 15s with sachets moistened with saline solution at 0.85% (w/v) [sodium chloride (Dinâmica®, Indaiatuba, SP, BR) diluted in type II purified water] with no disinfectant activity;
III) Control group B: the bacterial contamination around the outside of Female Luer extremity of the 3-WS was not submitted to manual friction with ethyl alcohol at 70% (w/v) or saline solution at 0.85% (w/v). This control group aimed to evaluate the experimental asepsis of sample collection to ensure the reliability of the microbiological analysis results.”.
In Results section:
Point 6: as resulted from Table 1, in the control group the same results were obtained as in the group with the alcoholic solution, which means that alcoholic solution is useless.
Point 7: the same reason makes the results have no clinical significance.
Responses 6 and 7: According to the presentation of the study groups:
III) Control group B: the bacterial contamination around the outside of Female Luer extremity of the 3-WS was not submitted to manual friction with ethyl alcohol at 70% (w/v) or saline solution at 0.85% (w/v). This control group aimed to evaluate the experimental asepsis of sample collection to ensure the reliability of the microbiological analysis results.”.
Thus, the results of this control group (Control group B) are similar to the intervention group (manual friction of the 3-WS samples with ethyl alcohol at 70%) because there was no microbial contamination during the experimental microbiological processing of the samples. In addition, the study has showed clinical relevance because the intervention group was better than the control group A (manual friction of the 3-WS samples with saline solution at 0.85% with no disinfectant activity).
Point 8: a post-hoc test would be necessary to show between which groups the statistically significant differences appeared.
Response 8: To make the results clearer, the control group B (the 3-WS were not submitted to manual friction with ethyl alcohol at 70% or saline solution at 0.85%) was excluded from the Table 1. Thus, the statistical comparison was performed only between the intervention group (the 3-WS were submitted to manual friction with ethyl alcohol at 70%) and control group A (the 3-WS were submitted to manual friction with saline solution at 0.85%).
Point 9: the final paragraph of this section - lines 185-187: the values discussed cannot be found in the two tables. Please correct this.
Response 9: The authors of the manuscript agree with the reviewer's consideration and the data of the results was added in the Table 2.
In Discussion section:
Point 10: lines 196-197: the null hypothesis was rejected, by the results, but the same results were obtained with the control group. The question is asked: why was a control group used, if the results were not compared with it?
Response 10: According to the presentation of the study groups:
III) Control group B: the bacterial contamination around the outside of Female Luer extremity of the 3-WS was not submitted to manual friction with ethyl alcohol at 70% (w/v) or saline solution at 0.85% (w/v). This control group aimed to evaluate the experimental asepsis of sample collection to ensure the reliability of the microbiological analysis results.”.
Point 11: lines 202-203: please reformulate the phrase "All external surfaces, 40% of lumens, and 86.7% of dressing presented bacterial growth", as it gives the impression that these results are obtained from the present study.
Response 11: The authors of the manuscript agree with the reviewer's consideration and the sentence was modified and made clearer to:
“According to Rossini et al. (2017), all external surfaces, 40% of lumens, and 86.7% of dressing presented bacterial growth…”.
Point 12: comments should be added on the fact that similar results were obtained in the study group with alcohol and the control group.
Response 12: The authors of the manuscript agree with the reviewer's consideration and this information was added in the manuscript:
“Control group B showed no bacterial contamination, which confirmed the experimental asepsis during sample collection and, consequently, the reliability of the microbiological analysis results.”.
Point 13: study limitations are not presented - please add
Response 13: The authors of the manuscript agree with the reviewer's consideration and the study limitations were included in the manuscript:
“The limitations of this study are due to the use of only two types of bacteria within a huge microbial variety related to the hospital environment contamination and healthcare-associated infections. In addition, bacteria were used in the planktonic state and the disinfection process was not evaluated against bacteria in the biofilm state, which are more tolerant to chemical and physical agents.”.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear Authors, please address the following questions/concerns and include in the context of the article:
It is not mentioned if this practice is local, universal, etc?
What are the other methods of des-infections are there that is safer and more efficient, compare to what addressed in this article?
At what circumstances and what is the probability of the dis-infection to be a risk to human?
Any recommendation for revising the dis-infection procedure, method, etc?
Has this research done in biosafety cabinet?
Has a sensitivity analysis been done for the data?
Author Response
Comments and Suggestions for Authors
Author's Reply to the Review Report (Reviewer 2)
Dear Authors, please address the following questions/concerns and include in the context of the article:
Point 1: It is not mentioned if this practice is local, universal, etc?
Response 1: This practice can be considered universal, but developing countries may perform it more frequently, because developed countries make more frequent use of antimicrobial caps.
Point 2: What are the other methods of des-infections are there that is safer and more efficient, compare to what addressed in this article?
Response 2: Perhaps the use of antimicrobial caps reported by manufacturers. However, more studies are needed to assess their degree of efficiency.
Point 3: At what circumstances and what is the probability of the dis-infection to be a risk to human?
Response 3: The risk to human health may be associated with the disinfectant (inadequate concentration of the active ingredient) and/or the technique (inadequately performed) used in the disinfection process.
Point 4: Any recommendation for revising the dis-infection procedure, method, etc?
Response 4: According to the conclusion of this study:
“The manual friction with ethyl alcohol at 70% (w/v) of the three-way stopcocks (3-WS) demonstrated antibacterial efficacy, but it refers to reflections on the risk of solution diffusion into the venous network and the inherent challenges of non-controlled clinical practice situations regarding patient safety.”.
Point 5: Has this research done in biosafety cabinet?
Response 5: Yes, all microbiological tests were carried out inside the biological safety cabinet, allowing the asepsis of all technical procedures performed. This information is in the second paragraph of the Material and Methods (“The microbiological step was performed in a Class II Type A1 Biological Safety Cabinet…”).
Point 6: Has a sensitivity analysis been done for the data?
Response 6: A sensitivity analysis was not performed in this study.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Dear Authors,
Thank you for responding to my observations and considering my recommendations in the revised version of your manuscript entitled "Manual friction with ethyl alcohol at 70% (w/v) to disinfect three-way stopcocks".
