Reviewer's report 
 Quality control in colorectal cancer screening: Microbiological investigation of endoscopes in Title: 
the NORCCAP (Norwegian Colorectal Cancer Prevention) trial: a survey 
Authors: 
Dr Michael Bretthauer ( michael.bretthauer@sthf.no )
Anita Jorgensen ( anita.jorgensen@sthf.no )
Bjorn-Erik Kristiansen ( bjorn.erik.kristiansen@telelab.no )
Bjorn Hofstad ( bjorn.hofstad@ioks.uio.no )
Dr Geir Hoff ( hofg@online.no )
 1  30 Apr 2003 Version: Date: 
 Paul Rozen Reviewer: 
 A paper whose findings are important to those with closely related research Level of interest: 
interests 
 Accept after discretionary revisions Advice on publication: 
There have been many studies of bacterial contamination of endoscopes, transmission of infection 
and means of cleaning and high-level disinfection. However, there are relatively few studies of 
systematic evaluation of endoscope contamination in an ongoing colorectal cancer-screening program in an asymptomatic population. This is an important issue, which is addressed and brought to the attention of persons planning and performing a screening program. 
The manuscript needs to be improved by language editing and by providing more definitive 
statements on methodology. 
Discretionary Revisions 
1. The title should reflect that this is a Systematic microbiological evaluation of endoscopes used in 
the ... 
2. Abstract, 2nd sentence, suggest starting "Since endoscopes cannot be sterilized, the transmission 
....". 
3. Abstract, line 11. It would be useful to indicate what the percentage of endoscopies performed do the 178 samples represent. 
4. Abstract, last sentence is not clear. I assume the authors mean "Improvement of equipment 
design and cleaning procedures ...". 
COMPULSORY REVISIONS 
1. Language needs to be improved by scientific and language editing. There are incomplete 
sentences indicating an idea, but it is not fully expressed. 2. In the abstract and text it is important to indicate how many flexible sigmoidoscopy examinations 
were performed and how many instruments were used. What percentage of these examinations 
does the 178 samples represent. 
3. Page 3, line 11, "bronchoscope, not adequately designed" this is not clear. I assume that the sentence should finish" to allow adequate cleaning. 
4. Page 4, line 2 states "samples were frequently taken". This needs to be expanded upon in the 
section on Methods. Were they systematically taken or just at random? If so, on how many 
endoscopes? 
5. Page 5, lines 1-3 refer to cleaning guidelines. Even though they are published, it would be useful 
to summarize them in a table. In what way did your cleaning protocol differ as bacterial contamination was detected on the endoscopes? 6. Sampling for bacterial contamination seems adequate. On page 6, Results refers to center I and 
center II. In the Methods Section, it needs to be stated how many screening centers were there and 
in what way did they differ what is the fault of the methods used. 7. Page 6, Results, Enterobacteriaceae is incorrectly spelled. The bacterial infections detected were mainly of environmental origin and only a few represented fecal contaminations that had not been 
dealt with adequately during the cleaning and disinfection stages. This is discussed on page 7. 
8. Page 7, line 2. The word "significant" does not seem appropriate, as we don't really know if this is a statistically significant finding. 9. Page 7, paragraph 1, last sentence, add reference 9. 
10. Page 7, paragraph 2, line 5, suggest using the word "we improved the cleaning process ...". It 
would be useful for the readers if the authors explained why the enzyme solution and rinsing with 
alcohol improved the cleaning process. 
11. Page 7, describe your current cleaning and disinfection protocol and in what way does it differ 
from ref. 2. This could probably be placed in a table comparing the two protocols. 
12. Page 8, line 4 refers to "Continuous microbiological ..." probably the word "systematic" is more appropriate. However, at what cost, will it significantly affect the screening program? 13. Page 8, last sentence refers to "disposable sheaths". Add a reference and briefly describe the 
advantages of the sheath and in what way can the standard instruments be improved so as to 
facilitate cleaning. 
Competing interests: 
None declared. 
Reviewer's report 
 Quality control in colorectal cancer screening: Microbiological investigation of endoscopes in Title: 
the NORCCAP (Norwegian Colorectal Cancer Prevention) trial: a survey 
Authors: 
Dr Michael Bretthauer ( michael.bretthauer@sthf.no )
Anita Jorgensen ( anita.jorgensen@sthf.no )
Bjorn-Erik Kristiansen ( bjorn.erik.kristiansen@telelab.no )
Bjorn Hofstad ( bjorn.hofstad@ioks.uio.no )
Dr Geir Hoff ( hofg@online.no )
 1  30 Apr 2003 Version: Date: 
 Paul Rozen Reviewer: 
 A paper whose findings are important to those with closely related research Level of interest: 
interests 
 Accept after discretionary revisions Advice on publication: 
There have been many studies of bacterial contamination of endoscopes, transmission of infection 
and means of cleaning and high-level disinfection. However, there are relatively few studies of 
systematic evaluation of endoscope contamination in an ongoing colorectal cancer-screening program in an asymptomatic population. This is an important issue, which is addressed and brought to the attention of persons planning and performing a screening program. 
The manuscript needs to be improved by language editing and by providing more definitive 
statements on methodology. 
Discretionary Revisions 
1. The title should reflect that this is a Systematic microbiological evaluation of endoscopes used in 
the ... 
2. Abstract, 2nd sentence, suggest starting "Since endoscopes cannot be sterilized, the transmission 
....". 
3. Abstract, line 11. It would be useful to indicate what the percentage of endoscopies performed do the 178 samples represent. 
4. Abstract, last sentence is not clear. I assume the authors mean "Improvement of equipment 
design and cleaning procedures ...". 
COMPULSORY REVISIONS 
1. Language needs to be improved by scientific and language editing. There are incomplete 
sentences indicating an idea, but it is not fully expressed. 2. In the abstract and text it is important to indicate how many flexible sigmoidoscopy examinations 
were performed and how many instruments were used. What percentage of these examinations 
does the 178 samples represent. 
3. Page 3, line 11, "bronchoscope, not adequately designed" this is not clear. I assume that the sentence should finish" to allow adequate cleaning. 
4. Page 4, line 2 states "samples were frequently taken". This needs to be expanded upon in the 
section on Methods. Were they systematically taken or just at random? If so, on how many 
endoscopes? 
5. Page 5, lines 1-3 refer to cleaning guidelines. Even though they are published, it would be useful 
to summarize them in a table. In what way did your cleaning protocol differ as bacterial contamination was detected on the endoscopes? 6. Sampling for bacterial contamination seems adequate. On page 6, Results refers to center I and 
center II. In the Methods Section, it needs to be stated how many screening centers were there and 
in what way did they differ what is the fault of the methods used. 7. Page 6, Results, Enterobacteriaceae is incorrectly spelled. The bacterial infections detected were mainly of environmental origin and only a few represented fecal contaminations that had not been 
dealt with adequately during the cleaning and disinfection stages. This is discussed on page 7. 
8. Page 7, line 2. The word "significant" does not seem appropriate, as we don't really know if this is a statistically significant finding. 9. Page 7, paragraph 1, last sentence, add reference 9. 
10. Page 7, paragraph 2, line 5, suggest using the word "we improved the cleaning process ...". It 
would be useful for the readers if the authors explained why the enzyme solution and rinsing with 
alcohol improved the cleaning process. 
11. Page 7, describe your current cleaning and disinfection protocol and in what way does it differ 
from ref. 2. This could probably be placed in a table comparing the two protocols. 
12. Page 8, line 4 refers to "Continuous microbiological ..." probably the word "systematic" is more appropriate. However, at what cost, will it significantly affect the screening program? 13. Page 8, last sentence refers to "disposable sheaths". Add a reference and briefly describe the 
advantages of the sheath and in what way can the standard instruments be improved so as to 
facilitate cleaning. 
Competing interests: 
None declared. 
Please review this paper.
user
Reviewer's report 
 Quality control in colorectal cancer screening: Microbiological investigation of endoscopes in Title: 
the NORCCAP (Norwegian Colorectal Cancer Prevention) trial: a survey 
Authors: 
Dr Michael Bretthauer ( michael.bretthauer@sthf.no )
Anita Jorgensen ( anita.jorgensen@sthf.no )
Bjorn-Erik Kristiansen ( bjorn.erik.kristiansen@telelab.no )
Bjorn Hofstad ( bjorn.hofstad@ioks.uio.no )
Dr Geir Hoff ( hofg@online.no )
 1  30 Apr 2003 Version: Date: 
 Paul Rozen Reviewer: 
 A paper whose findings are important to those with closely related research Level of interest: 
interests 
 Accept after discretionary revisions Advice on publication: 
There have been many studies of bacterial contamination of endoscopes, transmission of infection 
and means of cleaning and high-level disinfection. However, there are relatively few studies of 
systematic evaluation of endoscope contamination in an ongoing colorectal cancer-screening program in an asymptomatic population. This is an important issue, which is addressed and brought to the attention of persons planning and performing a screening program. 
The manuscript needs to be improved by language editing and by providing more definitive 
statements on methodology. 
Discretionary Revisions 
1. The title should reflect that this is a Systematic microbiological evaluation of endoscopes used in 
the ... 
2. Abstract, 2nd sentence, suggest starting "Since endoscopes cannot be sterilized, the transmission 
....". 
3. Abstract, line 11. It would be useful to indicate what the percentage of endoscopies performed do the 178 samples represent. 
4. Abstract, last sentence is not clear. I assume the authors mean "Improvement of equipment 
design and cleaning procedures ...". 
COMPULSORY REVISIONS 
1. Language needs to be improved by scientific and language editing. There are incomplete 
sentences indicating an idea, but it is not fully expressed. 2. In the abstract and text it is important to indicate how many flexible sigmoidoscopy examinations 
were performed and how many instruments were used. What percentage of these examinations 
does the 178 samples represent. 
3. Page 3, line 11, "bronchoscope, not adequately designed" this is not clear. I assume that the sentence should finish" to allow adequate cleaning. 
4. Page 4, line 2 states "samples were frequently taken". This needs to be expanded upon in the 
section on Methods. Were they systematically taken or just at random? If so, on how many 
endoscopes? 
5. Page 5, lines 1-3 refer to cleaning guidelines. Even though they are published, it would be useful 
to summarize them in a table. In what way did your cleaning protocol differ as bacterial contamination was detected on the endoscopes? 6. Sampling for bacterial contamination seems adequate. On page 6, Results refers to center I and 
center II. In the Methods Section, it needs to be stated how many screening centers were there and 
in what way did they differ what is the fault of the methods used. 7. Page 6, Results, Enterobacteriaceae is incorrectly spelled. The bacterial infections detected were mainly of environmental origin and only a few represented fecal contaminations that had not been 
dealt with adequately during the cleaning and disinfection stages. This is discussed on page 7. 
8. Page 7, line 2. The word "significant" does not seem appropriate, as we don't really know if this is a statistically significant finding. 9. Page 7, paragraph 1, last sentence, add reference 9. 
10. Page 7, paragraph 2, line 5, suggest using the word "we improved the cleaning process ...". It 
would be useful for the readers if the authors explained why the enzyme solution and rinsing with 
alcohol improved the cleaning process. 
11. Page 7, describe your current cleaning and disinfection protocol and in what way does it differ 
from ref. 2. This could probably be placed in a table comparing the two protocols. 
12. Page 8, line 4 refers to "Continuous microbiological ..." probably the word "systematic" is more appropriate. However, at what cost, will it significantly affect the screening program? 13. Page 8, last sentence refers to "disposable sheaths". Add a reference and briefly describe the 
advantages of the sheath and in what way can the standard instruments be improved so as to 
facilitate cleaning. 
Competing interests: 
None declared. 
assistant