I'm quite frequently asked whether the development of antimicrobial resistance in C. pneumoniae is likely, particularly when starting with one antibiotic or when adding metronidazole intermittently. To be honest I think the emergence of antibiotic resistance is unlikely, given that the organism in not actively replicating while in the cryptic form. I've put a new page on my website which discusses this: http://www.davidwheldon.co.uk/resistance.html Do forward comments and criticisms.
(Editor's note: I've attached this post to the Handbook as-is so that readers may see Dr. Wheldon's article directly on his site through the provided link as well as the discussion here at www.cpnhelp.org . That way readers will have access to the most up-to-date version should he edit it on his site. Jim K)