Prevalence and Associated Factors of optrA-Positive-Enterococcus faecalis in Different Reservoirs around Farms in Vietnam

Round 1

Reviewer 1 Report

An et al. have done a nice piece of work related to AMR gene dissemination in one health context. However, the study needs a minor revision before accepting it.

Introduction

Line 74-75: Rearrange the sentence to “In Enterococcus faecalis, LZD resistance is often related to the presence of otrA gene.”

Lie 126-127: rephrase it as the current version did not give a clear idea

Line 127-129: give a valid reference

What are the approved antibiotics that can be used for the veterinary purpose in Vietnam?

What is the reported prevalence of MDR enterococci in Vietnam and regional countries?

Materials and Methods

Kindly mention the ethics details of the study somewhere in lines 394-401

How many different types of flies did the researchers consider for the study?

What are the reference strains used in the study? Please state it in line 422

Line 433-434: On what ground did the researchers consider intermediate susceptibility as resistant? Kindly provide acceptable references and justification.

Discussion

What could be the possible reasons for the four E. faecalis isolates were phenotypically resistant but optrA negative as mentioned in Line 167?

What are the limitations of the current study?

What will be the future direction of the current study findings?

Explain the importance of tackling the AMR burden according to the One-Health perspective.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The study was aimed at assessing prevalence of a gene responsible for linezolid resistance in Enterococcus faecalis and determining the factors associated with it. The manuscript is generally of high quality and I noticed no major issues in any of its parts.

However, the quality of the illustrations is suboptimal and has to be improved. I recommend that Figures 1A and 1B should have their own numbers, since there are already independent captions in place. Use black font and uniform style of the backgrounds. Label vertical axes. Figure 2 should be improved so that it does not contain distorted symbols. The caption is normally given as a text, not as a part of an image.

Minor points:

Check the use of capital letters and italics in gene names.

Line 77. Check small and capital letters in OPEFs.

Line 84. Check spelling of otrpA.

Line 85. PFGE pulse types —> PFGE types.

Line 104. Write vanA, vanB without the spaces (PMID: 9041416; PMID: 21396533).

Line 127. “The lack of facilities”. Please clarify. Apparently, something like lavatories/latrines/wastewater/(poor) hygienic practices is mentioned here. A specific citation supporting the statement is desirable.

Line 214. All E. faecalis isolates were susceptible to penicillin and ampicillin, but almost all were multidrug resistant. Is it your original result? Why another source is cited?

Line 261. Genes have no ability to infect somebody or something by their own.

Line 269. Portugal.

Line 385. Singular-plural mismatch.

Line 429. Provide a reference to specific CLSI protocol, not only to performance standards. If changes were made, describe them.

Please place Conclusion before the Materials and Methods.

I think, data availability statement section can be removed, since the study did not generate special data needing deposition.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The authors declared, “Carriage of OptrA positive Enterococcus faecalis in humans,animals, and environment on farms in Vietnam and associated factors   ”. Despite the importance of the study, the article lacks a good presentation. It has many grammar and language mistakes.

The order of event writing should be the same either in the abstract, introduction, material, ……….so on.

The title of the study needs to be more appropriate

An expert in the English language should revise it before publishing. The following major points must be taken into consideration:

Abstract:

-Line 75 gene name is wrong

- Keywors should be arranged in alphapetic and modified

- The authors may improve the abstract and make it concise

Introduction:

-The introduction needs to be more informative. The introduction should be improved(illustrating the aim of the work,importance of enterococcus):

·        Line 97 and should be added to fluoroquinolone

·        Line 119 protect change to protects

·        Line 120 linezolid resistant change to linezolid-resistant

·        Line 134 community change to communities

·        The objective of this study needs to be rewritten

Results

-  Line 157 mean change to a mean

-Line 171 add and in wastewater

-Line 212 were change to was

-Line 282 figures change to figure

- Line 244 was change to were

-Please illustrate MDR and its percentage and for which number of classes as authors focused on MDR in the introduction and not mentioned in results

Discussion and conclusion

-Authors need to improve discussion and explore the significance of the study compared to other studies.

-Line 261 infected change to were infected

-Line 276 please add and to eduction

-Line 371 preventing to prevent

-Line 388 remove about

- Line 389 expanding change to expand

Methods

-Line 415 supplement changed to a supplement

- Samples which did not find out E. faecalis, Explain why , authors must consider negative as a total not OPEfs negative

- Line 418 were change to was

- Please add classes of used antibiotics

-Bacteria must be written in italic

-Statistical analysis should be added and explain the program 

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

In the manuscript titled “Carriage of OptrA positive Enterococcus faecalis in humans, animals, and environment on farms in Vietnam and associated factors.” The authors planned to investigate the prevalence of optrA-positive E. faecalis in humans, chickens, pigs, dogs (feces), wastewater and flies on farms and 2) identify the association between the presence of this bacteria and the genetic relationships of optrA-positive E. faecalis isolates in livestock settings.

The study design is not clear. The authors aimed to determine the prevalence of optrA-positive E. faecalis in different sample types. However, they did not identify the sample size and how they performed the randomization for sample collection.

Please reduce the abbreviations in the abstract section.

L75: “otrA presence” typo

L99: “antibiotic resistant infections” Please rephrase it.

L107: Please add references to support this information.

L145: Although the authors studied the associated epidemiology factors of optrA-positive E. faecalis in different sample types, they did not include this part in the aim of their study. Also, they did not include this part in the introduction section.

L407: What does the author mean by wastewater? What is the volume per sample? How they processed it for bacteriological examination?

L406: “The feces of animals were collected by investigators.” More details are required, did fecal samples collected from individual animals, or in some circumstances, like in chicken farms, were pooled samples collected?

L407-409: The authors collected the flies using a glue board, then aseptically and individually transferred them into 1.5 ml Eppendorf tubes. Did the authors examine them bacteriologically as individual samples or pool them for each farm?

L159: Table 1 presents the characteristics of investigated population and farms; what about the dog population? The authors examined the feces of 51 dogs from 51 farms. Is there only one dog on each farm?

L214: “almost all were multidrug-resistant isolates” How did the authors determine the MDR?

L214-215: Table 3 does not present the results of linezolid. It is not clear how many isolates were phenotypically resistant and how many of them carried the optrA gene.

The authors did not list any limitations of their study.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The Authors profoundly revised the MS and provided satisfactory replies to the comments and suggestions. However, the text did not receive a thorough final check. Particularly, I have the following requests.

Line 85. Farm livestock unit. Actually, I find this phrase to be very vague. If you perform a search with the quotes on https://scholar.google.com/, so that a key phrase looks like "farm livestock unit", there will be very limited number of matches. There may be a need to revise the name of this important factor in the whole manuscript.

Line 222. antimicrobials did not include —> antimicrobials were not included.

Table 2. Check mean positive values in the sections Flies (N=109) and Wastewater (N = 67).

In the first round, I recommended that Figure 2 should be improved so that it does not contain distorted symbols. In the amended version of the MS, nothing changed in this regard. The current name of the illustration is Figure 3.

Lines 569-579. I understand your adherence to the template, but please check if the following statement is more suitable: The data presented in this study are available in article (https://www.mdpi.com/2079-6382/12/5/825). I do find the current form inadequate.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Thanks for great efforts in improving the manuscript 

Author Response

Thank you for your acceptance. We checked across the manuscript again and corrected remaining mistakes on English language and style.

Reviewer 4 Report

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf