What are these particles?

This specimen is voided urine sample of 38-year-old woman, and stained by PAP using liquid based preparation method.  I found many of these particles dispersed all over the slides and sometimes loosely aggregated each other.

This specimen contains lots of vaginal squamous cells, so there is also a possibility of vaginal contents. I suspected Trichomonas vaginalis at first look on the low power magnification. However, on a closer look, it looked like some kind of particles or microorganisms. Any comments are welcome!