Bacteriocins

Bacteriocins are relatively small antimicrobial peptides synthesized by the ribosomes of most known bacteria (e.g., Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria)
Lopetuso et al. 2019 Int J Mol Sci. 20: 183

Although the influence of bacteriocins on animal intestinal microorganisms is well understood, bacteriocins have not yet been used in human medicine; hence the specific effects of bacteriocins on the human gut microbiota remain unknown.
Pu et al. 2022a Front. Nutr. 9: 877948

The previous studies had mostly used in vitro fermentation systems where feces and bacteriocins were co-fermented to investigate the effects of bacteriocins on gut microbiota in vitro.
Pu et al. 2022a Front. Nutr. 9: 877948

Bacteriocins are proteinaceous or peptidic toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strain(s)

see also:
Antimicrobial peptides (AMPs) & Mode of Action (MoA)
Defense Systems / Defense Mechanisms
Lactobacillales / Lactic acid bacteria (LAB)
Microbial products
Pathogens / Pathobionts / Pathogenic Bacteria & Probiotics (living agents)
Pyocins