**4. Summary and future prospects of probiotics as antimicrobial agents**

The probiotics are offering a ray of hope to solve dwindling antibiotic efficacy. Further, the number of immunocompromised persons, number of microbial infections and drug resistance, and probiotics could come in handy to solve these problems. Therefore, there is a need for detailed conclusive research on *in vitro, in vivo,* and clinical trials of probiotic microorganisms, prebiotics, and postbiotics administration including, the benefits and side effects. The choice of probiotics, methods, and experimental designs need to be emphasized. Research has demonstrated that probiotics of a particular strain may have antimicrobial activity against one pathogen and not another [9, 10, 14]. This has been attributed to the great diversity of virulence factors expressed by these pathogens. Some pathogens can produce exoenzymes, encode resistance genes, form biofilms, and induce inflammatory responses, among others [37, 101, 102]. The probiotic dosage, duration, frequency, formulation, viability, species-level, and strain, among others, should always be reported for conclusive studies. Otherwise, it would be pretty challenging to compare these experiments and draw a definite conclusion. Some particular probiotics do not show any antimicrobial activity *in vitro* but present significant activity *in vivo* and vice versa. Hence, there is a need for meticulous screening of probiotic microorganisms before the antimicrobial activity is or is not confirmed.

## **Author details**

Janet Cheruiyot Kosgey1,2,3\*, Mercy W. Mwaniki1 and Fengmin Zhang2,3

1 School of Biological and Life Sciences, Technical University of Kenya, Kenya

2 Department of Microbiology, Harbin Medical University, Harbin, China

3 WU Lien-Teh Institute, Harbin Medical University, Harbin, China

\*Address all correspondence to: jantomeli@yahoo.com; janet.kosgey@tukenya.ac.ke

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
