Culture-Independent Quantitative PCR Detected Mobilized Colistin Resistance Genes (mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5) in Chicken Gut Contents in Bangladesh

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In sci-3178197, Asad et al reported the detection of mobilized colistin resistance genes (mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5) in chicken-gut contents in Bangladesh using quantitative PCR detected. The topic  of the manuscript is interesting and fits well the scope of the journal. The reviewer feels it need extensive amendments before it can be accepted.

(1) The writing is so-so. The authors have to seek editorial assistance to improve their presentation.

(2) Line 80: The acquisition and transferability of the plasmid-mediated mobilized col-79 istin resistance gene variant-1 (mcr-1) was first reported in Enterobacterales bacteria from animal 80 products and humans in China [20] in 2026,  It is still 2024 today. How can it be 2026?

(3) The authors should briefly review the legal status for  addition of colistin as animal feed supply？  

(4）Do the authors detect what kind of bacteria carry  colistin resistance genes?

 

 

Author Response

Please find the attachement.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This work investigated the prevalence of mobilized colistin resistance (mcr) genes in chicken gut contents in Bangladesh using real-time quantitative polymerase chain reaction (RT-qPCR). Significantly, 47.5% of the fresh poultry droppings were found to exhibit the presence of at least one mcr gene out of the five variants investigated. Although the authors fail to explore the reasons behind the different prevalence of mcr genes in various regions, this work has a complete structure, reasonable methods, precise data analysis and valuable conclusions. This manuscript could be accepted after the following problems are resolved:

(1) In lines 82-83, the authors mentioned that “ten lightly different genotype variants of the transferable mcr-1 gene (mcr-1 to mcr-10) have been reported”, please explain the reason of only detecting five mcr genes (mcr-1 to mcr-5).

(2) Please provide a detailed description of the usage of antibiotics in commercial poultry farms and household farms during the past three months, including whether using colistin.

(3)  Please analyze the cause responsible for experimental results. For example, is the higher mcr gene content in poultry droppings from commercial poultry farms related to the greater use of antibiotics?

(4) In the discussion, please advise how to suppress the transmissions of mcr genes, how to strengthen the supervision of antibiotics usage, how to promote environmentally friendly commercial poultry farms, and so on.

(5) In lines 45 and 317-318, the word “adopted” is inappropriate and could be replaced with “considered”.

(6) In line 81, “2026” should be changed to “2016”, according to the reference [20].

(7) In lines 122-123, “80 fresh poultry droppings were collected from 16 from commercial poultry farms” has a redundant word “from”.

(8) In lines 160-161, please pinpoint the usage amount of each primer as 5 μmol or 2 μL.

(9) In figure 2, please change the first several letters of the title to a format that is not bold.

Author Response

Please see the attachement.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript has been improved and appears to be acceptable.