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Introduction
Infertility affects relatively a large number of couples of about 186 million globally.1 Many reports have indicated that the fertilizing potential of semen in healthy men is declining over a period.2- 4 Epidemiological studies also show that the sperm concentration in United States declines by 1.5% per year and by 3% in Australia and Europe.5 Significant declines in sperm count, motility, and morphology have also been reported in Denmark,6 Sweden,7 France,8 Austria9 and Finland.10 Similarly, mean concentration of spermatozoa in Italy has also fallen down.11
At present, semen analysis performed based on the WHO laboratory manual for the examination and processing of human semen is considered to be the standard method for semen examination, where the semen parameters such as semen volume, pH, sperm concentration, motility, morphology, etc. are evaluated.12 Modern life-style changes, high stress levels, smoking, alcohol consumption, lack of exercise, exposure to radiations could be the possible causes of decline in the seminal parameters.13 Apart from all these factors, the genital tract infection plays a vital role in declining the seminal parameters and has a direct impact on male infertility.14 A number of studies report that 8-32% of male infertility cases are associated with infections and inflammation of the male genitourinary tract by microorganisms such as bacteria, virus, fungi, and protozoa.15-17 Infection with these microorganisms lead to infertility problems such as sperm damage, pyospermia, asthenospermia, teratospermia, etc by adversely affecting the spermatogenesis, causing inflammatory disorder, anatomical obstruction, scaring and initiating leukocyte response with its concomitant oxidative stress.18
Bacteriospermia, the infection with bacteria is one of the major and significant factors in male infertility that result in abnormal semen parameters and even lead to impairment of sperm functions and seminal tract obstruction.19, 20 However, in most of the occasions, this bacteriospermic condition among men does not considered as one of the obstacles in fertility treatment when compared to all other investigative factors such as hormone levels and irregularities in menstruation cycles among women. Even though numerous studies independently report the effect of bacteriospermia on seminal parameters, only a few studies highlighted the importance in sperm DNA fragmentation and Reactive Oxygen Intermediates (ROI). This review discusses on various...