Alteration of semen characteristics and regulatory factors in human semen with bacterial infection

Effects of bacteria on male fertility: Spermatogenesis and sperm function

Bacterial infection can negatively affect different parts of the male genital tract and subsequently cause impaired spermatogenesis and male fertility. However, most of the previous studies have focused on the infected organs of the male genital tract and there are not many studies that investigated the direct effect of bacteria on sperm and their mechanism of action. Interestingly, bacteria can induce different damages on sperm cells such as DNA fragmentation, cell membrane peroxidation, and acrosome impairment. Such negative effects can be mediated by bacteria-secreted toxins and metabolites or by direct attachment of bacteria on the sperm cells and subsequent activation of signaling pathways related to oxidative stress, apoptosis, and inflammation. These bacteria-induced changes can impair semen parameters and subsequently cause infertility. Given the significant destructive effect of some bacteria on sperm function and male fertility, in this study, we reviewed the impact of male urogenital bacteria on spermatogenesis and sperm functions as well as the underlying mechanisms by which the bacteria can damage sperm.

SIGNIFICANCE OF SEMEN CULTURES FOR MEN WITH QUESTIONABLE SEMEN QUALITY

Semen cultures often yield inconclusive results probably due to bacterial contaminants. We were able to isolate enteric pathogens with greater specificity by comparing two cultures from the same individual: one obtained from the midstream urine and the other from ejaculate obtained following midstream urine collection and eliminating the bacteria present in the midstream urine. Bacterial growth was found in semen cultures from 102 (79%) of the 129 men with questionable semen quality; 31 (30%) had aerobic bacteria, 28 (27%) had anaerobic bacteria, and 43 (42%) had both. A high incidence of positive cultures in our study was probably due to stringent patient selection and our comparative culturing procedure. The presence of pathogens may indicate the need for treatment especially prior to IVF and IUI.

Bacteria trigger oxygen radical release and sperm lipid peroxidation in in vitro model of semen inflammation

OBJECTIVE

To assess the in vitro effect of five bacterial strains isolated from semen samples (Escherichia coli, Staphylococcus haemolyticus, Streptococcus oralis, Bacteroides ureolyticus, and Ureaplasma urealyticum) on reactive oxygen intermediate (ROI) release and lipid sperm membrane peroxidation in the coincubated suspensions of white blood cells (WBC) with spermatozoa.

DESIGN

An in vitro model of semen infection.

SETTING

Basic research laboratory.

PATIENT(S)

Healthy normozoospermic volunteers and healthy blood donors.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Chemiluminescent assay was used to evaluate ROI generation by WBC. Malondialdehyde (MDA) concentration was determined in sperm lysates using high-performance liquid chromatography.

RESULT(S)

Of the bacterial strains tested, B. ureolyticus, S. haemolyticus, and E. coli caused the greatest damage to sperm membrane lipids. An increase in MDA levels in sperm lysates was a natural consequence of bacteria-induced ROI generation. The WBC usually enhanced harmful activity of the infectious agent toward the cell membranes.

CONCLUSION(S)

The harmful effect of bacteria on spermatozoa depends on the type and species of microorganisms invading, colonizing, or infecting the male genital tract and is associated with the accompanying oxidative stress. The presence of leukocytes in semen appears to be the additional factor enhancing the sperm lipid membrane peroxidation, which may affect the fertility status.

Prostatitis and male infertility: evidence and links

Prostatitis and infertility are common disorders in men and many researchers have investigated a possible link between the two disorders. After almost 3 decades of research the answer to this question remains unknown, although ample evidence exists to support a relationship between male infertility and prostatitis. This paper discusses this evidence and then derives a rational treatment approach to the man with infertility and prostatitis.