Diverse Bacteriocins Produced by Strains From the Human Milk Microbiota

Abstract

Microbial colonization of the infant gut is a convoluted process dependent on numerous contributing factors, including age, mode of delivery and diet among others that has lifelong implication for human health. Breast milk also contains a microbiome which acts as a source of colonizing bacteria for the infant. Here, we demonstrate that human milk harbors a wide diversity of bacteriocin-producing strains with the potential to compete among the developing gut microbiota of the infant. We screened 37 human milk samples and found isolates with antimicrobial activity and distinct cross-immunity profiles. From these isolates, we detected 73 putative gene clusters for bacteriocins of all known sub-classes, including 16 novel prepeptides. More specifically, we detected two novel lantibiotics, four sactibiotics and three class IIa bacteriocins with an unusual modification of the pediocin box that is composed of YDNGI instead of the highly conserved motif YGNGV. Moreover, we identified a novel class IIb bacteriocin, four novel class IIc and two class IId bacteriocins. In conclusion, human milk contains a variety of bacteriocin-producing strains which may provide them a competitive advantage in the colonization of the infant gut and suggests that the milk microbiota is a source of antimicrobial potential.

Nocathioamides, Uncovered by a Tunable Metabologenomic Approach, Define a Novel Class of Chimeric Lanthipeptides

“…The leader peptide possessed the conserved FDLN motif and towards its C‐terminal end two proline residues (Figure 1 ), which typically occurs in prepeptides of class I lantibiotics and suggest, with P commonly located at position −2, two putative cleavage sites. [13] To complicate matters further, NtaA contains in addition one characteristic tandem alanine “AA” and two “PA” cleavage sites [14] which give rise to multiple possibilities for dividing the precursor peptide into an N‐terminal leader peptide and a C‐terminal core peptide. Application of the automated web‐based tool RIPPMiner [15] corroborated these findings and predicted the formation of a 12 or 14mer.…”

The Microbiota of the Human Mammary Ecosystem

“…The human milk microbiota may contribute to, at least, some of the functional properties and health benefits that epidemiological studies have associated with breastfeeding (Renfrew et al, 2012), including protection against infections, metabolic programming, immunomodulation and neuromodulation. Human milk bacteria may provide a certain degree of protection against infections caused by viruses, bacteria or fungi through a variety of mechanisms: (a) biosynthesis of compounds with antimicrobial activity, including organic acids (lactic acid, acetic acid, ethanol), bacteriocins, reuterin or hydrogen peroxide (Heikkilä and Saris, 2003;Beasley and Saris, 2004;Martıń et al, 2005;Martıń et al, 2006;Caŕdenas et al, 2016;Caŕdenas et al, 2019;Angelopoulou et al, 2020;Garcıá-Gutierrez et al, 2020); (b) coaggregation with pathobionts, impeding their access to the gut epithelial cells (Caŕdenas et al, 2019); (c) competitive exclusion with pathobionts for nutrients or host receptors (Olivares et al, 2006a;Martıń et al, 2010;Langa et al, 2012); (d) reinforcement of the infant gut barrier by preserving and decreasing intestinal permeability and increasing mucin biosynthesis (Olivares et al, 2006a;Vanhaecke et al, 2017;Liu et al, 2020); and (e) inmmunomodulation (Liu et al, 2020).…”

Molecular Characterization of Microbiota in Cerebrospinal Fluid From Patients With CSF Shunt Infections Using Whole Genome Amplification Followed by Shotgun Sequencing

“…Another 6 genomes (SEPI) were ICU isolates from neonatal or critical care units at the University of Washington Medical Center ( Roach et al., 2015 ). 4 genomes (APC) were from isolates from human milk obtained in Ireland ( Angelopoulou et al., 2020 ).…”