Following several potentially high risk exposures over the years, I had a course of co-amxiclav, containing 125mg amoxicillin prescribed last November, 3x daily for I think 4 days, could possibly have been 5. I am not sure whether or not this course was completed. 

My questions are:

1) had I acquired syphilis prior to this and it were in the secondary or latent phase - would a negative Total Antibody Treponemal EIA/CIA taken 8 months later this June have been categorical proof that I either was never infected or the infection had been cured? 

2) from why I have read, once the infection is at the secondary phase or later, even if treated, the treponemal tests will remain positive for life and seroreversion occurs only when very early primary cases are treated? 

3) could the co-amoxiclav in any way have partly treated the infection to the point of diminishing antibodies to a rate where they read as level, however not fully cured it and therefore become a problem in the future?

 

Many thanks for all your help once again. 

Question 3 ought to have asked if there was any possibility that the co-amoxiclav had partially treated latent or late syphilis to a point where the treponemal screening test would have read negative 7 or 8 months later, but not actually fully cured? 

For reference - my reason for testing in the first place was being informed a previous partner from several years ago was positive - unknown duration. 

You needn't worry at all. Since you don't describe the nature of your sexual exposures that might have risked syphilis nor do you mention any symptoms, I cannot judge the likelihood you actually were exposed. However, for sure you do not have it now and probably never did. The antibiotics you took are very active against Treponema pallidum -- the bacteria that causes syphilis -- so in theory if you had been exposed in the 2-3 weeks preceding that treatment, an incubating case could have been aborted or a very early case treated. It was not the recommended treatment either in terms of the particular drugs or the duration you took them, but even brief exposure to such very active antibiotics likely would abort an incubating case and might even cure an early established case. In any case, your subsequent negative test result prove you do not have syphilis now and there is no possibility of a relapse, i.e. no future syphilis is possible from your various sexual experiences over the years. 

Those comments pretty well address your specific questions, but to assure clarity:

1. Your negative tests are proof you do not have syphilis, and almost certainly never had it.

2. It seems you understand:  the screening tests (e.g. RPR, VDRL) routinely become negative after treating syphilis, but seroreversion of confirmatory tests happens only when the infection is treated within a few weeks of acquiring it.

3. Your negative tests prove you don't have syphilis now. If you had inadequately treated latent syphilis, your blood tests would be positive.

As for a long-ago exposure to a partner with positive test of unknown duration, most such persons are no longer infectious to partners. Syphilis generally is not transmissible after a year, i.e. even infected people almost never pass the infection on to their partners.

So all is well. No need for further testing for syphilis:  you don't have it! I hope these comments have been helpful. Let me know if anything isn't clear.

HHH, MD

For context, any potential exposure I had was 2 or 3 years previous to my taking co-amoxiclav and therefore more than 2 or 3 years prior to testing. It was with a male who himself was diagnosed with latent/late stage. 

Just to finish up, and I promise this will be it -

1) does this change anything in your thinking - I understand the 3/4 days of co-amoxiclav would probably be insufficient in treating what would be a latent or late case of syphilis, so would there be a chance of it partially curing the disease to the point a treponemal test would not detect, however not fully treating?

2) I have read in the past that you said you believed false negative treponemal tests to be virtually nonexistent - is the same true of treponemal tests missing very low levels of antibodies in late/partially treated infection? 

Thank you again for your help. 

2) More overthinking. The treponemal tests ALWAYS are positive for life unless syphilis is treated within the first few weeks of infection. Anybody levels have nothing to do with it, as far as known.

Accept that you do not have syphilis and stop searching the web on it. Like many anxious people, you're being misled by information you don't understand and concluding that somehow you're the exception to a solid, long time rule. It isn't worth it!