Review for 10.1186/s12876-020-01200-7 (2020)

Reviewer’s report
Title: Infection Control in ERCP using a Duodenoscope with a Disposable Cap (ICECAP):
Rationale for and Design of a Randomized Controlled Trial
Version: 0 Date: 25 Nov 2019
Reviewer: Philippe Saliou
Reviewer's report:
This study protocol deals with an important question regarding the persistent bacterial contamination of
duodenoscopes after reprocessing. Gastroenterological endoscopes are associated with outbreaks and
this risk has increased with the spread of highly resistant bacteria.
The  novel  design  of  duodenoscope  that  employs  a  disposable  cap  theoretically  limits  bacterial
contamination but no study has been published to demonstrate it.
1. Will the study design adequately test the hypothesis? 
Yes the study design will adequately test the hypothesis. The study population and the eligibility
criteria are correct. Patients  are randomized and the study outcomes will allow answering to the
objectives.
However it is a monocentric study.  
 
2. Are sufficient details provided to allow replication of the work or comparison with related analyses:
if not, what is missing? 
Some clarifications must be made:
Will all duodenoscopes used in the study be new? Rates of contaminations are linked to the age of
endoscopes  and  it  has  previously been  proven  that  the  risk of  persistent  bacterial  contamination
increased with the use of endoscopes. Damaged endoscopes can be difficult to disinfect. How many
duodenoscopes will be used for the study and will their use be comparable?
Will all the duodenoscopes be reprocessed by the same type of automated endoscope reprocessor? Will
they all be stored in the same type of cabinet?
Concerning microbiological analysis:
the study protocol is adapted from the Duodenoscope Surveillance Sampling and Culturing Protocols
and can be replicate in every center. The procedure of sampling is well described and can be repeated at
every center. The presence of any post-reprocessing bacterial population will be assessed after 72 hours
of culture as recommended by the protocol, however time of incubation can influence results and we
recommend incubating plates for 5 days. Indeed, growth of bacteria has already been described after
more than a week of incubation.
Persistent bacterial contamination will be defined as growth of any identifiable microorganism at ≥20
CFU.  Will  the  presence  of  microorganisms  such  as  enterobacteriae,  Staphylococus  aureus  or
Pseudomonas sp will be accepted even under 20CFU? 
What will happen if microbiological testing failed to comply with the target level? Will duodenoscopes
be subject to a new reprocessing and retested? Will they be sent to the manufacturer for maintenance?  
3. Is the planned statistical analysis appropriate? 
Yes.
The PBC rate of over 20% after standard duodenoscope disinfection is correct. A relative risk reduction
of 75% is ambitious but not impossible to reach. The number of patients to include is correct for
primary outcome 1 and primary outcome 2.
4. Is the writing acceptable?
Yes the writing is acceptable but some details should be added concerning microbiological analysis.
All in all, this is a good study of major interest. This RCT may yield important answers concerning the
interest of novel duodenoscopes making use of disposable elevator cap.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
No
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 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.
I am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
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