Prostatitis: PCR Detection of Bacteria

Bacteria gene sequencing is revolutionizing the detection of pathogens. Highly conserved gene sequences for plymerase chain reactions (PCR) make it possible to detect bacteria from all known genera in one assay. Such PCR analyses of clinical specimens have led to estimates that as few as 5% of pathogens have ever been detected by clinical laboratory culture systems.

Techniques to detect bacterial genes in semen specimens were developed by Bedford Research Foundation scientists. Assay sensitivity was set to detect only abundant organisms, greater than 20,000 per ml of semen. A study conducted to measure the incidence of abundant organisms in semen specimens form men undergoing fertility assessment revealed:

    • 60% of men had positive specimens
    • Elevations in semen leukocytes did not always correlate with bacteria.
    • Eschericia coli was not detected
    • Streptococcus mitis, Lactobacillus crispatus, and Staphylococcus species were identified organisms.
    • Many of the semen bacteria were not listed in GenBank; in agreement with prostate biopsy studies from other laboratories, the unidentified bacteria were most closely related either to gram positive anaerobic cocci, such as Peptostreptococcus species, or to Corynbacteria species.

Ongoing studies of semen specimens from men with prostatitis indicate this will be a useful test to determine if they have bacterial, or non-bacterial, prostatitis.

Leukocyte Immunostain

In the past, distinguishing leukocytes from immature sperm forms in semen was limited to the detection of leukocyte peroxidases. These tests are technically difficult and do not detect lymphocytes and monocytes.

The patented method developed at Bedford Research Foundation preserves semen cells in suspension, allowing cytologic assessments not possible with specimens that aren’t preserved. Monoclonal antibodies used routinely by pathology laboratories to distinguish leukocytes and their subtypes tag the same cells in the €xed semen specimens red-brown. (Fig. 1) This approach makes it possible to distinguish leukocyte subtypes such as lymphocytes and granulocytes from immature sperm.

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