Table 2.

Selected bacteria infecting men and their consequences on male fertility

Bacteria	Infected genital organs	Damage to genital tract organs	Causes of male infertility
Chlamydia trachomatis	• Urethra [107–109] • Prostate [110, 111] • Epididymis [108, 112] • Testis [113] • Seminal vesicles and semen [111, 114–116]	• Urethritis [107, 117] • Prostatitis [110] • Epididymo-orchitis [107] • Epididymitis [112] • Seminal vesiculitis [114] • Enlarged seminal vesicles [109]	• Controversial [118]
Escherichia coli	• Urethra [119] • Prostate [120] • Testis [121, 122] • Epididymis [108] • Seminal vesicles [123–125]	• Prostatitis [120, 126] • Urethritis and urethral discharge [119] • Epididymo-orchitis [119, 121, 122] • Testicular pain and swelling [121] • Testicular infarction [121, 122] • Scotal, testicular, seminal vesicle and prostatic abscesses [121–125]	• Controversial but association with poor sperm parameters [127, 128]
Mycobacterium tuberculosis	• Urethra [129, 130] • Prostate [131–135] • Seminal vesicles [132, 136] • Testis [131, 137, 138] • Epididymis [131, 139, 140]	• Urethral fistula [129, 130] • Urethral stricture [129, 130] • Enlarged prostate [129, 131, 133] • Prostatitis [131, 133] • Urethral, prostatic, testicular and epididymal granulomatous lesions [130, 131, 133, 137–139] • Urethral, prostatic, testicular and epididymal necrosis [130–134, 137, 138] • Enlarged seminal vesicles [136] • Prostatic, seminal vesicle and testicular calcifications [131, 136, 137] • Scrotal, prostatic and seminal vesicle abscesses [129, 132, 134, 135] • Enlarged testis [131, 132, 138] • Enlarged epididymis [131, 132, 136, 139] • Epididymitis [129, 139, 140] • Scrotal pain and swelling [137, 138, 140]	• Undefined cause [140] • Azoospermia [129, 136, 141]
Neisseria gonnorhoeae	• Urethra [108, 142] • Semen [143, 144]	• Urethritis and urethral discharge [108] • Dysuria [108] • Epididymo-orchitis [142] • Higher prostate cancer risk [145, 146]	• Controversial [106] however: • Temporary or permanent oligozoospermia to azoospermia [142]
Staphylococcus aureus	• Seminal vesicles and semen [127, 147–156] • Testis [157] • Prostate [125, 151, 158, 159]	• Seminal vesicle, prostatic and testicular abscesses [125, 150, 151, 157, 159, 160] • Epididymo-orchitis [150, 157] • Foci of prostatic and testicular necrosis [157, 160] • Enlarged and tender prostate [125, 150, 151, 158, 160] • Dysuria [125, 150, 151, 157, 158]	• Controversial [148, 152–155]
Treponema pallidum	• Semen [161, 162] • Penis [162, 163] • Testis [164–166]	• Penile and scrotal lesions [162] • Scrotal or testicular swelling [163–165, 167–169] • Testicular gummas [165, 167–170] • Atrophy/destruction of seminiferous tubules [164, 168, 170] • Destruction of testicular parenchyma [168] • Testicular obliterative vasculitis [164] • Orchitis [165, 168, 169] • Epididymo-orchitis [164, 166, 167] • Higher prostate cancer risk [146, 171]	• Not directly reported
Ureaplasma urealyticum	• Urethra [172] • Semen [173–179] • Expressed prostatic secretions [110, 180] • Epididymis [181]	• Urethritis [182] • Epididymitis [181, 183] • Chronic prostatitis [110, 179, 180] • Possible association with prostate cancer [184]	• Controversial effects on spermatozoa [173–175, 177, 178] • Elevated ROS in semen [179]

This table summarizes the organ location of eight bacteria that are known to infect the male genital tract. It also specifies the damage to these organs and the proven or possible causes of male infertility as reported in the literature

ROS reactive oxygen species