Protocol for the Evaluation of Bactericidal Activity of Hard, Non-porous Copper/Copper Alloy Surfaces
(2/03/15 Version)
Sehulster Review and Commentary on Comments Submitted to EPA Under Separate Cover by Other Entities
                                       
I will address the comments made by other entities in chronological order from earliest to most recent.  Unless I am mistaken, it appears that the comments file had duplicate comments for two entities/persons:  Dr. Mary Bruch and Mr. Diego Ugarte.
Re: Comments from Ms. Rhonda Jones (no date of submission)
Ms. Jones is commenting on the version of the potency test method released on 09/19/14.  Her first major point of concern is the duration and details (or lack thereof) of the method to evaluate the effects of abrasive action and chemicals.  She raised good questions, asking for clarification and background information.  The revised EPA test protocol of 02/03/15 addresses these questions.  The majority of Ms. Jones' comments are questions about specific details of the method in which she asks for explanations and additional steps to better eliminate process variations among labs.
 Her level of scrutiny is typical for a person who has extensive experience reviewing lab methods for microbial inactivation for registration purposes, and her questions are reasonable.  As for the task presented to me as part of the Letter Review of the revised lab method dated 02/03/15, my sense was that EPA wanted me to respond to general questions about the revision.  Had the agency's instructions for the Letter Review indicated that EPA wanted a step-by-step critique of the revised method, I would have done that.  My comments and questions would have aligned with those of Ms. Jones on the details.  However, I made a mental note that the agency appeared to be moving away from exquisitely detailed protocols, thereby allowing some room for process variation.  The lab technician, however, would have to make note of all the details done in some of the steps for EPA review and documentation.
Re: Comments from Dr. Mary Bruch (no date of submission)
Dr. Bruch is commenting on the version of the potency test method released on 09/19/14.  Her comments to the agency are similar to those of Ms. Jones, concentrating on detailed information needed for various steps in the protocol, with some editorial comments.  Dr. Bruch also has extensive experience in providing method reviews that are highly detailed and specific.  She raises an interesting point of discussion about "surface products" or "product surfaces."  The EPA revised method of 02/03/15 does not appear to comment on this question.
My statement that the 02/06/15 method appears to be reasonable is made with the awareness that several of the steps in the revised method could be more detailed, but my sense is that the agency is allowing some lab variation on some of the steps so long as the lab provides the agency with the details about said variations.  If my assumption is wrong, then yes  -  the method details as pointed out by these two reviewers should be addressed by the agency.
Re: Comments from Mr. Alastair Monk
Mr. Monk discusses a few major items in his comments.  The first point is the number and identity of the challenge microorganisms (he recommends only two, these being Staphylococcus aureus and Pseudomonas aeruginosa).  In my opinion, I view the agency's recommended challenge microorganisms of S. aureus, P. aeruginosa, and Enterobacter aerogenes to be appropriate selections for this reason  -  these bacteria are representative of bacteria commonly found on skin (S. aureus), bacteria found in water (P. aeruginosa), and bacteria found in fecal matter (E. aerogenes).  This selection covers the three main sources of contaminated reservoirs we would most likely encounter in settings where copper- and copper alloy fixtures and surfaces would be used for infection prevention.  Mr. Monk does make two good points about the abrasive test, saying that there should be a dry version and a wet version of the test, and a representative quaternary ammonium compound should be used in place of EDTA-phosphoric acid as one of the chemicals.  In concept, I would support these suggestions, but other reviewers have commented that in their opinion the abrasive testing phase of the overall test protocol is both labor- and time-burdensome.  With regards to contact time, Mr. Monk supports the two-hour exposure period, so he doesn't appear to comment on the notion of continuous potency.          
 Re: Comments from Mr. Andrew Kireta (CDA)
Mr. Kireta's two major points of discussion are the following: 1) the need to demonstrate continuous inactivation of microbes by copper and copper alloys; and 2) the need for the agency to gear up for validation testing of the protocol via intra-lab studies and inter-lab comparative studies.  My previous submission of comments to EPA centered on these two points as well.  Knowing the EPA laboratory professionals, I'm confident that the agency will pursue validation studies on this or any testing method they promote for regulatory purposes.  With regards to the issue of continuous potency, I have not seen any earlier version of the protocol in which this topic may have been considered, but a test does need to be developed to support any claim for continuous potency.  
Re: Comments from Mr. Diego Ugarte
Mr. Ugarte joins the other commenters in his questions about the abrasive test.  He basically asks about the rationale for the agency's selection of chemicals and experimental design points, and what happens from a registration viewpoint when a test lab misses the requisite number of test runs.  If EPA produces another revision to this method, responses to Mr. Ugarte's questions would be very helpful not only to him but to all the laboratorians who will be thinking of offering this testing to their clients for product registration.
Re: Comments from Mr. Kon John (Olin Brass)
Mr. John basically wants to keep the status quo.
Re: Comments from Mr. Joseph Green (CDA)
Mr. Green corroborates the earlier comment from his colleague Mr. Kireta regarding the issue of demonstrating continuous potency.  As I mentioned in my comments on the protocol and repeated elsewhere in this document, a validated lab method must be developed (if one doesn't already exist) in order to generate those data in support of a continual inactivation claim.  The lab test protocol dated 02/03/15 does not achieve this objective, as it clearly indicates a contact of two hours.  
     
