Reviewer ’s report  
 
Title: Prevalence of clarithromycin resistance in Helicobacter pylori  in Santiago, Chile, 
estimated by real -time PCR directly from gastric mucosa  
 
Versi on: 1 Date: 03 Nov 2017  
 
Reviewer: Dong H. Kwon  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
attachment. Please only upload as attachments anno tated versions of manuscripts, graphs, 
supporting materials or other aspects of your report which cannot be included in a text format.  
Please overwrite this text when adding your comments to the authors.  
 
Title:  
Prevalence of dual clarithromycin and metron idazole resistance in Helicobacter pylori estimated 
by molecular methods in Santiago, Chile  
 
Summary:  
Authors extracted DNA from 191 gastric mucosa samples and detected 93 of them showing H 
pylori -positive. Among the 93 H. pylori -positive DNA, 29 of them c arried mutations on 23S 
rDNA (A2142G and/or A2143G) and assumed as clarithromycin resistant DNA. Among the 29 
clarithromycin resistant DNA, 3 of them showed rdxA -truncation/deletion mutations and 11 of 
them showed missense mutations.  
 
Comments:  
Authors pro vided DNA sequencing data that concluded 31.8 % of clarithromycin resistance and 
14.0 % of dual resistance to clarithromycin/metronidazole in Santiago, Chile. The DNA 
sequencing data for the clarithromycin resistance may not be a question. However, the DNA  
sequencing data for the metronidazole resistance will be seriously criticized by readers because 
of the 14.0% of the dual resistance. Three samples of rdxA DNA sequences (two truncations and 
one in -frame deletion) may be clear to be metronidazole resistan t DNA, but the 11 samples of 
rdxA DNA sequences (missense mutations) may or may not be metronidazole resistant DNA. 
The missense mutations do not guarantee to cause metronidazole resistance, in particular 
showing only DNA sequence data.  
Are the methods appropriate and well described?  
If not, please spe cify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown ? 
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
 
Quality of written English  
Please indicate the quality of language in the manuscript : 
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in  any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to t he content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing intere sts' 
below.  If your reply is yes to any, please give details below.  
 
NA 
 
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my name d report  
including any attachments I upload will be posted on the website along with the authors'  
responses.  I agree for my report to be made available under an Open Access Creative Commons 
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do  not wish to be included in my named report can be included as confidential comments 
to the  editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
Reviewer ’s report  
 
Title: Prevalence of clarithromycin resistance in Helicobacter pylori  in Santiago, Chile, 
estimated by real -time PCR directly from gastric mucosa  
 
Versi on: 1 Date: 03 Nov 2017  
 
Reviewer: Dong H. Kwon  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
attachment. Please only upload as attachments anno tated versions of manuscripts, graphs, 
supporting materials or other aspects of your report which cannot be included in a text format.  
Please overwrite this text when adding your comments to the authors.  
 
Title:  
Prevalence of dual clarithromycin and metron idazole resistance in Helicobacter pylori estimated 
by molecular methods in Santiago, Chile  
 
Summary:  
Authors extracted DNA from 191 gastric mucosa samples and detected 93 of them showing H 
pylori -positive. Among the 93 H. pylori -positive DNA, 29 of them c arried mutations on 23S 
rDNA (A2142G and/or A2143G) and assumed as clarithromycin resistant DNA. Among the 29 
clarithromycin resistant DNA, 3 of them showed rdxA -truncation/deletion mutations and 11 of 
them showed missense mutations.  
 
Comments:  
Authors pro vided DNA sequencing data that concluded 31.8 % of clarithromycin resistance and 
14.0 % of dual resistance to clarithromycin/metronidazole in Santiago, Chile. The DNA 
sequencing data for the clarithromycin resistance may not be a question. However, the DNA  
sequencing data for the metronidazole resistance will be seriously criticized by readers because 
of the 14.0% of the dual resistance. Three samples of rdxA DNA sequences (two truncations and 
one in -frame deletion) may be clear to be metronidazole resistan t DNA, but the 11 samples of 
rdxA DNA sequences (missense mutations) may or may not be metronidazole resistant DNA. 
The missense mutations do not guarantee to cause metronidazole resistance, in particular 
showing only DNA sequence data.  
Are the methods appropriate and well described?  
If not, please spe cify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown ? 
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
 
Quality of written English  
Please indicate the quality of language in the manuscript : 
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in  any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to t he content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing intere sts' 
below.  If your reply is yes to any, please give details below.  
 
NA 
 
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my name d report  
including any attachments I upload will be posted on the website along with the authors'  
responses.  I agree for my report to be made available under an Open Access Creative Commons 
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do  not wish to be included in my named report can be included as confidential comments 
to the  editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
Please review this paper.
user
Reviewer ’s report  
 
Title: Prevalence of clarithromycin resistance in Helicobacter pylori  in Santiago, Chile, 
estimated by real -time PCR directly from gastric mucosa  
 
Versi on: 1 Date: 03 Nov 2017  
 
Reviewer: Dong H. Kwon  
 
Reviewer's report:  
 
Please include all comments for the authors in this box rather than uploading your report as an 
attachment. Please only upload as attachments anno tated versions of manuscripts, graphs, 
supporting materials or other aspects of your report which cannot be included in a text format.  
Please overwrite this text when adding your comments to the authors.  
 
Title:  
Prevalence of dual clarithromycin and metron idazole resistance in Helicobacter pylori estimated 
by molecular methods in Santiago, Chile  
 
Summary:  
Authors extracted DNA from 191 gastric mucosa samples and detected 93 of them showing H 
pylori -positive. Among the 93 H. pylori -positive DNA, 29 of them c arried mutations on 23S 
rDNA (A2142G and/or A2143G) and assumed as clarithromycin resistant DNA. Among the 29 
clarithromycin resistant DNA, 3 of them showed rdxA -truncation/deletion mutations and 11 of 
them showed missense mutations.  
 
Comments:  
Authors pro vided DNA sequencing data that concluded 31.8 % of clarithromycin resistance and 
14.0 % of dual resistance to clarithromycin/metronidazole in Santiago, Chile. The DNA 
sequencing data for the clarithromycin resistance may not be a question. However, the DNA  
sequencing data for the metronidazole resistance will be seriously criticized by readers because 
of the 14.0% of the dual resistance. Three samples of rdxA DNA sequences (two truncations and 
one in -frame deletion) may be clear to be metronidazole resistan t DNA, but the 11 samples of 
rdxA DNA sequences (missense mutations) may or may not be metronidazole resistant DNA. 
The missense mutations do not guarantee to cause metronidazole resistance, in particular 
showing only DNA sequence data.  
Are the methods appropriate and well described?  
If not, please spe cify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
No 
 
Are the conclusions drawn adequately supported by the data shown ? 
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
 
Quality of written English  
Please indicate the quality of language in the manuscript : 
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in  any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to t he content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing intere sts' 
below.  If your reply is yes to any, please give details below.  
 
NA 
 
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepted for publication, my name d report  
including any attachments I upload will be posted on the website along with the authors'  
responses.  I agree for my report to be made available under an Open Access Creative Commons 
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do  not wish to be included in my named report can be included as confidential comments 
to the  editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
assistant