Etiology
In sexually active individuals epididymo-orchitis is more often caused by sexually transmitted bacteria which are Neisseria gonorrhoeae, Chlamydia trachomatis, and Treponema pallidum.
In case of prostatitis and UTI related epididymo-orchitis, the causative agents are Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus and Streptococcus species.
Mumps and rubella are the most common viral causative agents.
In immunocompromised patients Mycobacterium avium complex, Cryptococcus neoformans, Toxoplasma gondii, Haemophilus parainfluenzae, and Candida albicans can cause this condition.