The encounter you describe was a virtually no risk event.  In Germany, by law, commercial sex workers are checked regularly for STIs, making it unlikely that your partner had any STI.  Further, among penetrative sexual encounters, receipt of oral sex is amongst the lowest.  There are no proven cases of HIV acquired from receipt of oral sex and IF your partner had an oral STI (unlikely) there is little chance that her infection was transmitted to you.  The major STI transmitted by receipt of oral sex is gonorrhea and over 90% of men with gonorrhea have an obvious penile discharge with 3-5 days of exposure.  On the other hand, penile itching is not a sign of any STI although it is the sort of symptom that we see when worried persons are looking for symptoms.  In such situations, persons without infection tend to notice normal sensations as itching.  

In your situation I would have little concern.  If you are worried, at this time a urine specimen tested for gonorrhea will provide accurate results.  Many of our clients appreciate having a negative test result.  If you choose to test, I anticipate that your test will show that you are not infected.

I hope that this information is helpful.  EWH

Your self-medication with azithromycin further reduces the already virtually no risk nature of your exposure.  

I think you are worrying needlessly.  EWH

There is no evidence that you have given your wife anything

This completes this thread which will now be closed.  There should be no reason for you to return to the Forum.  EWH