Nisin A, a Class I lantibiotic commonly used as a food preservative, has been studied for its ability to kill pathogens. Yet, its effects on the beneficial bacteria in the human gut, known as commensal bacteria, still need to be better understood.
The gut has a delicate balance of microbes, and commensal bacteria are crucial for breaking down nutrients, producing helpful substances, and protecting against harmful bacteria. If antimicrobial food preservatives, like nisin A, kill too many commensal bacteria, harmful bacteria could replace them, leading to potential health issues similar to eating contaminated food.
A new study by scientists from the University of Chicago found that one of the most common classes of lantibiotics has potent effects against pathogens and the commensal gut bacteria that keep us healthy.
Nisin, a widely used lantibiotic found in various products like beer, sausage, cheese, and sauces, is produced by bacteria in cow mammary glands. Interestingly, microbes in the human gut also produce similar lantibiotics. Zhenrun “Jerry” Zhang, PhD, a postdoctoral scholar at the University of Chicago, aimed to investigate how naturally-produced lantibiotics, like those in the gut, affect the beneficial bacteria in the gut.
Researchers explored a public database of human gut bacteria genomes, discovering genes responsible for producing six gut-derived lantibiotics closely resembling nisin, including four new ones.
Collaborating with Wilfred A. van der Donk, Ph.D., at the University of Illinois Urbana-Champaign, they synthesized these lantibiotics to test their impact on both pathogens and commensal gut bacteria. The findings revealed that, although the lantibiotics had diverse effects, they effectively killed pathogens.
Zhang said, “This study is one of the first to show that gut commensals are susceptible to lantibiotics, and are sometimes more sensitive than pathogens. With the levels of lantibiotics currently present in food, it’s very probable that they might impact our gut health as well.”
Zhang and his team delved into the peptide structure of lantibiotics, aiming to enhance their understanding of their antimicrobial activity for potential beneficial applications. In a separate study, the Pamer lab demonstrated that a group of four microbes, including a lantibiotic producer, played a protective role against antibiotic-resistant Enterococcus infections in mice. Additionally, they are investigating the prevalence of lantibiotic-resistant genes among various populations to grasp how such bacteria colonize the gut under different conditions and diets.
Zhang said, “It seems that lantibiotics and lantibiotic-producing bacteria are not always good for health, so we are looking for ways to counter the potential bad influence while taking advantage of their more beneficial antimicrobial properties.”
Journal Reference
- Zhenrun Zhang et al. Activity of Gut-Derived Nisin-like Lantibiotics against Human Gut Pathogens and Commensals. ACS Chemical Biology DOI: 10.1021/acschembio.3c00577