Welcome back to the forum. Thanks for your continuing confidence in our servcies. I will be answering your question this time.
Mycoplasma hominis is an entirely normal bacteria, present in almost everyone's genital tract at least some of the time. It is shared by sex partners, and in that sex can be considered sexually transmitted. However, it is harmless. STD clinics and true STD experts never test for M. hominis; and when a test is positive, it does not need treatment. M. hominis therefoere is not a likely cause of your contiuing symptoms. Some clinics or doctors test for it, but it really isn't necessary. Whether positive or negative should make no difference in patients' diagnosis or treatment.
As for how you caught trichomonas, there's nothing mysterious there. It's an STD; in fact, by some estimates the most common of all STDs. Probably you were infected during the sexual exposure you asked about on the forum acouple of months ago. (It appears to be a good lession in the possibility of STD from ejaculation near but not in the vagina, as Dr. Hook described to you. Also, trich testing is usually not done in men, so it's common for men to carry it even when they believe themselves to be free of STDs.
in the past few years there has been laboratory reserch suggesting that Trichomonas vaginalis and Mycoplasma hominis can interact with one another: In lab experiments, MH seems to make TV grow more vigorously. I'm wondering whether your nurse is aware of that research and has taken its conclusion too far. This interaction has NOT been shown to have any effect in patients' symptoms due to either bacteria and probably does not make trichomonas harder to treat.
As for your other tests, all were highly reliable; you can be sure you don't have chlamydia or gonorrhea. However, the oral fluids HIV test is only fair at 5 weeks: for 100% assurance about HIV, have a lab based test, not a home test, (preferably a "4th generation" or "antigen-antibody" test) at least 6 weeks or more after your last sexual exposure. Also you don't mention a syphilis blood test. You should also have that, any time 6+ weeks after the last exposure. You definitely can expect negative results for both syphilis and HIV.
How was your trichomonas treated? If you received only a single dose of metronidazole (Flagyl), that treatment is about 90% relialble. For complete reassurance, ask your nurse or doctor about getting treated for 5 days. That will take care of it for sure, and also will prevent the infection from going dormant and reappearing at a later time.
As for why trich has had less publicity and is less well known than other STDs is a complex issue: even we experts don't fully understand it. But part of the reason is that complications are rare. Aside from an unpleasant vaginal dsicharge, trich rarely cuases serious problems. This is very different than gonorrhea, chlamydia, or syphilis, all of which commonly can become very serious or even life threatening. Also, until recent years, accurate testing was not readily available, and some doctors offices still do old fashioned tests that miss many infections. If and when women are tested for trich, they should insist on the nucleic acid amplification test, or NAAT (also called the DNA test), which is very accurate.
The final issue is your emotional reaction to trichomonas. I'm not sure where that comes from -- you're a better judge than I am -- perhaps just the mystery of it? If so, I hope the information above has helped. But I also have to wonder whether you're still being emotionally impacted by a sexual decision you seem to regret. If such feelings are part of the picture and don't clear up promptly, professional counseling might be a good idea. I suggest it from compassion, not criticism.
Anyway, I hope these comments are helpful. Let me know if anything isn't clear.