It appears that every once in a while someone posts
(http://forums2.gardenweb.com/forums/load/rosesant/msg03171418618.html)
(http://forums2.gardenweb.com/forums/load/roses/msg1011062029912.html)
symptoms similar to what is described in this scientific publication. It appears that this type of infection could be caused by what is commonly called "Fire blight:

http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-03-13-0273-PDN
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A summary of possible treatments is given at:
http://www.caes.uga.edu/publications/pubDetail.cfm?pk_ID=7333

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The following link leads to a complete 2013 scientific paper titled:
"Pathogenicity and infection strategies of the fire blight pathogen Erwinia amylovora in Rosaceae: State of the art"

http://mic.sgmjournals.org/content/159/Pt_5/823.full.pdf+html
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A specific study of the effects of hydrogen peroxide reports that 3% hydrogen peroxide is a sufficient concentration to kill the Fire Blight strains.

http://www.landesmuseum.at/pdf_frei_remote/PHY_37_3_0131-0138.pdf
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It appears that 3% hydrogen peroxide treatment may be useful. I say "may" as the review concludes: " However, knowing the bacteria is not enough, as it is essential to study the plant as well."
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Since it appears that the spread from plant to plant is slow (" Disease incidence was estimated to be approximately 0.5% on rosehips over 2 years within all survey areas,"), it appears that it may not be necessary to immediately destroy the infected plant. However, the infected cane should probably be removed. A discussion of classic sprays is found in the following link:

http://www.walterreeves.com/food-gardening/notes-on-fire-blight-control-from-a-plant-pathologist/

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Until research establishes how this problem should be "best treated" in roses, you may want to consider isolating the infected plant and spraying it with one of the recommended classic sprays. If you are unwilling to move the infected bush, you may want to consider spraying the neighboring roses with a 3 % drugstore type hydrogen peroxide solution. (The hydrogen peroxide solution should stimulate the plant's defense system and the hydrogen peroxide should also attack any Fire Blight bacteria on the surface of the plants.)

Here is a link that might be useful: link to scientific abstract about fire blight in roses