Microbiological diagnosis of chronic bacterial prostatitis

Chief of Clinical Pathology, Medical Specialist in Microbiology, Laboratorio Clínico Hematológico S.A. Medellín, Colombia. Prostatitis is one of the most frequent urological pathologies and a common reason for consultation in both men under and over 50 years of age. Chronic inflammation of the prostate may be the consequence of an unresolved acute local infection, as well as urinary tract infection, urethritis and epididymitis. Symptoms in this entity are present for at least 3 months and their spectrum is variable; sometimes they are even almost nonexistent.  Some patients report problems with erection, painful, premature or bloody ejaculation; however, most affected men manifest pelvic pain and obstructive or irritative urinary symptoms. It has been described that prostate infection is caused by bacteria in at least 20% of cases, with Escherichia coli being the main associated microorganism. Other enterobacteria such as Klebsiella spp., Proteus mirabilis, Enterococcus faecalis, etc., can also cause infection and, to a lesser extent, microorganisms such as Chlamydia trachomatis, Ureaplasma spp, Mycoplasma spp. and Corynebacterium spp. For microbiological diagnosis, it is recommended to culture several urine samples, before and after prostatic massage, as well as a sample of prostatic secretion, the results of which should be analyzed comparatively. From the point of view of the microbiology laboratory, it is concluded that it is prostatitis when:

• If in the Gram staining of post-massage urine and prostatic secretion 10 or more leukocytes per field are observed than in the pre-massage urine sample.
• If a bacterial count of 10 or more Colony Forming Units (CFU) of the same microorganism(s) is obtained in the post-massage urine culture as in the pre-massage urine cultures.

In this case it is considered that the isolated microorganism(s) are the cause of the prostatic infection.