A Critical Review on the Potential of Inactivated Bacteria in Counteracting Human Pathogens

Bacterial infections are a major global public health challenge, especially with increasing antibiotic resistance. Postbiotics, bioactive compounds produced by probiotics, have been proposed as a novel strategy to inhibit the growth of pathogenic bacteria and address antibiotic resistance. Similar to probiotics and certain food ingredients, postbiotics can also modulate beneficial microbial communities and ultimately contribute to host health. Postbiotics derived from probiotics may affect the physical and chemical conditions of the intestinal environment, and by enhancing the host's immune system, directly interfere with the metabolic pathways and signaling of pathogenic bacteria. Postbiotics inhibit biofilm formation, reduce the expression of antibiotic resistance genes, and enhance the efficacy of antibiotic therapies. They are effective against resistant bacteria such as Escherichia coli and Clostridium difficile and reduce the risk of dental infections caused by Streptococcus mutans. Some postbiotics, such as lactic acid and antimicrobial peptides derived from Lactobacillus and Bifidobacterium genus, help the immune system dealing resistant bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, and Helicobacter pylori. The review investigates the mechanisms of action and applications of postbiotics in the control of pathogenic bacteria and their role as a complement to existing treatments.