Reviewer ’s report  
 
Title: Cervical microbiota in women with cervical intra -epithelial neoplasia, prior to and after 
local excisional treatment, a Norwegian cohort study.  
 
Version: 0 Date: 30 Sep 2018  
 
Reviewer: James Malone -Lee 
 
Reviewer's report:  
 
I think that this is a good paper with an important message for a developing field. Whilst I think 
that the data and experiment are sound the report is marred by an over -analysis which is too 
much for the sampling and does not add anything to the key message, which is interesting in 
itself without any embellishment s. I think that this paper should be published but would suggest 
that the analysis be simplified in order to allow a better understanding of what is being reported.  
Page 8 Line 26/27 "included" should be included  
Page 8 Lines 24 to 34  
I am not too keen of derived variables or categories, as in this case, because the involve the risk 
of additional error. They are dealing with biological continua that are not really suitable to 
categorisation and the categories are inevitably arbitrary.  
 
Page 9  
Statistical tests  
I do not think that they should be using paired t -tests for the between group analyses. I doubt that 
the data are compliant with the parametric criteria so it would be better for them to stick to non -
parametric analysis typically  Kruskall Wallis for three group comparison and Mann -Whitney U 
test for two groups and the Wilcoxon signed -rank test for paired samples.  
"We analysed if women that underwent treatment, more often aquired bacteria than lost earlier 
detected bacteria."  
This is difficult to understand.  
I think that the statistics are overdone.  
There is no point in analysing quantitative differences in species before and after because they 
are not using reliable quantitative methods. The numbers are also too small for the statistical 
analysis of the dichotomies presence or absence of individual species.  
Thus they are limited to analysing the non -lactobacilli species dispersion - How many different 
species before and after? - it is as simple as that. Then how many had lact obacilli before and 
after?  
The trouble with using these repeated statistical tests is that they run into troubles with 
multiplicity and a statistical nightmare. Simplicity is a much better option.  
They do not have the statistical power to analyse a subgr oup (Aged <46) and should probably 
limit their contribution to no apparent difference in this small sample.  
 
Results  
"The bacteria composition in the LEEP group before and after LEEP as well as in the reference 
group are described in Supplementary Table 1 " 
It would make much more sense of have a table describing the species as, number of isolates and 
% of all isolates for each assessment and for the healthy controls. There is not need for all of the 
complicated sub -group analysis and categorisation it is too  confusing.  
The comparison before and after LEEP should stick to differences in lactobacilli isolation and 
non-lactobacilli dispersion (number of different species). There is not point in going on about the 
presence of individual microbial species because  it does not have any known significance.  
"We found no difference in the detection of bacterial species or the occurrence of the constructed 
broader groups according to HPV DNA positivity after LEEP, neither when analysing all women 
at six and 12 months ( Table 3) nor just women positive for bacteria before treatment "  
Adding in these subgroup analyses was not part of the deal and the underlined bit should go. 
There was no difference between the HPV DNA group - end of story  
I think that the cone depth ana lysis goes too far into another sub group analysis:  
"We found no association between the microbiota changes after LEEP and the cone depth" Say 
no more the subgroup analysis is not statistically sound.  
"Comparisons of microbiota in women planned for treat ment versus healthy references"  
This section should also be simplified - There was a greater non -lactobacilli species dispersion in 
the patients compared to the controls. That is it and it is an important finding because it is 
commensurate with data from other groups reporting on UTI - Disease is associated with 
increased species dispersion.[1 -3] 
1. Hilt EE, McKinley K, Pearce MM, Rosenfeld AB, Zilliox MJ, Mueller ER, et al. Urine is 
not sterile: use of enhanced urine culture techniques to detect resident  bacterial flora in the 
adult female bladder. J Clin Microbiol. 2014;52(3):871 -6. Epub 2013/12/29. doi: 
10.1128/jcm.02876 -13. PubMed PMID: 24371246; PubMed Central PMCID: 
PMCPMC3957746.  
 
2. Pearce MM, Hilt EE, Rosenfeld AB, Zilliox MJ, Thomas -White K, Fok C , et al. The female 
urinary microbiome: a comparison of women with and without urgency urinary 
incontinence. mBio. 2014;5(4):e01283 -14. Epub 2014/07/10. doi: 10.1128/mBio.01283 -14. 
PubMed PMID: 25006228; PubMed Central PMCID: PMCPmc4161260.  
 
3. Price TK, Du ne T, Hilt EE, Thomas -White KJ, Kliethermes S, Brincat C, et al. The Clinical 
Urine Culture: Enhanced Techniques Improve Detection of Clinically Relevant 
Microorganisms. J Clin Microbiol. 2016;54(5):1216 -22. doi: 10.1128/JCM.00044 -16. 
PubMed PMID: 26962083 . 
Are the methods appropriate and well described?  
If not, please specify 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.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in th e 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.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Not suitable for publication unless extensively edited  
 
  
Declaration of competing interests  
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