Review for 10.1186/s12876-018-0820-0 (2018)

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:  
 
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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?  
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Yes 
 
Does the work include the necessary controls?  
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No 
 
Are the conclusions drawn adequately supported by the data shown ? 
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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  
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