* During July-August I met with another male for a couple of weeks. Activities included unprotected oral, him rimming on me, my penis rubbing in between cheeks, and a couple of protected anal one top one bottom.

* Partner tests for hiv and syphilis before every encounter (we are regular).

* I test for syphilis, HIV, g / c both throat, urethra.*Aug 11 after meeting him, 5 days after last encounter and around 3 weeks since first, I tested urethral neg, day I last met him (2w after first) neg for throat.

* I met him again for a week on early sept. Same activities. 1 day after last encounter neg again on throat (5 days since first). 4 days after last (1 week after first) positive urethral for chlamydia.

* He claims he has not been with anyone since before we met in August.

* I also have a stable female partner I trust 100% and don't want to risk, hence all the testing, I don't engage in any sexual acitivy till tests are back.

Questions:

* I was treated yesterday with 1g az single dose, no follow ups (UK recommends 500mg for 2 days more). Sexual encounters in Mexico. Will this effectively cure me? When is it safe to engage with my female partner again? I won't have access to testing for 20 days, can I go ahead safely? Do I need retest?

* Is it possible chlamydia lived on male's partner throat since before Aug and I was just lucky not to catch it earlier? If none of him or I have met anyone else (aside my female, who again, I trust 100%) how could I be positive in the Sept test? Are false positives possible? What can cause them?

* I have zero symptoms and home test for UTI revealed no leukocytes (or maybe traces? Hard to read) I have read that chlamydia would increase leukocytes count. Could this be more evidence towards false positive?

It's difficult to know when and how you acquired your chlamydial infection. My best guess would be one of the protected insertive anal events, perhaps with an unrecognized condom failure. Of course your presumed negative urethral chlamydia test after that suggests otherwise, but the tests aren't perfect. Conceivably it was from the more recent oral exposure, except that chlamyida is uncommon in the throat; when present is usually transient and also is detection of DNA only, without viable/transmissible organisms; and therefore oral to genital chlamydia transmission is quite rare. But yes, it probably is possible your partner had oral/pharyngeal chlamydia, missed on testing, since August.

One bottom line is that mysterious chlamydia test results are pretty common and in that sense your situation isn't unusual. However, the bad news -- you might agree-- is that I cannot guarantee you didn't have it during one or more of your sexual events with your female partner. Also, while I understand your confident in your female partner's sexual fidelity, you will understand that from my perspective -- decades of experience with couples in situations like yours -- the possibility she has had other partners is a consideration. (As a general principles, when one member of a couple has outside sexual desires and contacts, often the other is in a similar situation.) Just about any STD specialist would advise you to assure your partner is examined, tested and treated on account of potential exposure -- although in this case, treatment might be deferred pending her test result.

It's quite common for urethral chlamydia to cause no detectable elevation of urethral or urine WBCs. False positive test results are rare -- a lot less common than false negatives. (Urine or urethral testing routinely misses 5-10% of infections.)

Your treatment was good but perhaps not great. Evolving data the last few years reveal azithromycin is less reliable in curing chlamydia than once thought. That said, the main problem is we now know it fails to cure 5-10% of infections in women and up to 25% of rectal infections. However still pretty good (probably 95% reliable) against male urethral infection. Doxycycline for 7 days is now the preferred treatment for all infections, especially in women and for known rectal infection. The additional azithromycin doses common in the UK might reduce the risk of treatment failure, but it still would be wise for you to have another urine or urethral test to be sure you were cured.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD