Microbiota; A basic approach in terms of its effects on male fertility/ infertiliy status and sperm quality

Aim

The aim of this review is to reveal the relationship between

microbiota and male fertility/infertility.

Method

In the review writing, search engines such as ScienceDirect,

PubMed, Google Scholar were used in terms of literature

service. Studies between 1961-2022 were utilized with the help

of keywords such as "microbiota, semen, infertility".

Literature Information

Studying and researching diverse microbial communities offers

the opportunity to better understand both our own physiology

and environmental factors and systems. Analysis methods such

as metagenomics, sequencing technology and bioinformatics

contribute in this sense. Microbiota is clusters of physiological

and pathogenic microorganisms and they are found on the inner

and outer surfaces of all multicellular organisms from plants to

animals. Microbiota; while it contributes to the development of

the immune system, has also important roles on skin, urinary

system, respiratory system, digestion and absorption of

nutrients, production of vitamins, development and functions

of the gastrointestinal immune system. Besides, the living

body provides a rich nutrient environment for the survival of

microorganisms. Environmental factors such as mode of birth,

diet, use of antibiotics and drugs, geography and lifestyle also

affect the microbiota. Microbiota includes bacteria, archaea,

protists, fungi and viruses. From this perspective, microbiota

may be responsible in the pathogenesis of diseases, especially

in the development of idiopathic diseases. On the other hand,

microbial infections of genital tract that can cause inflammation

of tissues, obstruction of genital tract, epididymitis and

orchitis may lead to infertility. Pathogenic and apathogenic

microorganisms such as bacteria, viruses and fungi in semen

are seen that there are negative effects on spermatological

parameters. Infection and inflammation of the male genital tract

may negatively affect on sperm quality such as morphological

changes, acrosome exocytosis, sperm agglutination, decreased

sperm motility and membrane integrity. Approximately 15% of

male infertility is caused by genital tract infection. However, no

causative agent was determined in 30% of male infertile cases,

and when the semen microbiota of the patients in this group is

compared with the semen microbiota of healthy men, there are

some changes in the profile of microorganisms. A significant

decrease was found in the Lactobacillus ratio, especially in

the microbiota of infertile cases. This change may impair

sperm quality. The most common microorganism in semen

is bacteria and they are in the beneficial and harmful classes.

Bacteriospermia causes infertility in males, besides decrease

in pregnancy rate and early embryonic death in females. The

main transmission site of infectious agents in semen of animals

is the preputium. Other sources of contamination; feces,

inflammatory foci in the genital tract, semen collection and

processing equipment, animal caretakers, laboratory personnel

and semen extenders. Semen contaminated with bacteria

such as Enterobacteriaceae can adversely affect the quality of

semen used in methods such as artificial insemination and in

vitro fertilization, and also play an important role as hygiene

indicator. Even though most of the bacteria in semen are

non-pathogenic, they can adversely affect sperm quality and

longevity if present in high concentrations. Bacteriospermia

is a frequently encountered situation in applications such as

artificial insemination. Therefore, some antibiotics are added to

the extenders while preparing the semen. On the other hand,

considering the application of probiotics in connection with

the treatment process, the fact that oxidative stress triggers

sperm damage and that probiotics have antioxidant activity

has led to the idea that they can be used in treatment.

Conclusion

Many microorganisms play a role in causing infertility in

humans and animals. Although there have been studies

explaining the role of microbiota in the organism in recent

years, it is important to create optimum health conditions of

the body by understanding the molecular mechanisms and the

immune response potential of the host in more detail.