[2] Less common microbes include Ureaplasma, Mycobacterium, and cytomegalovirus, or Cryptococcus
in patients with HIV infection. E. coli is more common
in boys before puberty, the
elderly and homosexual men.
Non-infectious causes are also possible. Reflux of sterile urine (urine without bacteria) through the ejaculatory ducts may cause inflammation with obstruction. In children, it may be a response following an infection with enterovirus, adenovirus or Mycoplasma pneumoniae.