“Breastfeeding: A Powerful Ally in the Fight Against Antimicrobial Resistance”

Breast milk, particularly colostrum, is not only a source of nutrition but also a critical player in the early defense system of infants. Breast milk contains bioactive components that can effectively prevent the growth of antibiotic-resistant bacteria in newborns, particularly in light of the growing threat that antibiotic resistance (AMR) poses to world health. Lets explore how breast milk help fight AMR.

The Bioactive Elements in Breastmilk.

Breast milk is a complex fluid that helps strengthen an infant’s immune system by having a variety of bioactive substances. Compared to mature milk, colostrum, the first milk produced after childbirth, has much higher amounts of secretory immunoglobulin A (sIgA) and immune cells. By absorbing and killing pathogenic microbes, these elements shield newborns from intestinal infections and offer active immunity against them. Antigens and enteric bacteria that the mother has been exposed to are the targets of sIgA, which is produced by lymphocytes in the mammary gland. These microorganisms include antibiotic-resistant pathogens like Shigella and Campylobacter.

By preventing access to intestinal epithelial receptors, attaching to bacterial adhesion sites, encasing the bacteria in mucus, and opsonizing them so that immune cells can identify them, sIgA facilitates pathogen clearance. Furthermore, sIgA provides defense against pathogen-mediated diarrhea by directly neutralizing bacterial virulence factors and toxins .

Gut Health and Human Milk Oligosaccharides (HMOs)
Human milk is a unique source of structurally varied glycans called HMOs, which have a significant role in influencing the gut microbiome of infants. HMOs operate as a substrate to beneficial bacteria, such as species of Bifidobacterium, which can colonize the infant’s gut and inhibit the growth and development of bacteria resistant to antibiotics. For instance, Bifidobacterium longum subsp. infantis effectively breaks down HMOs into acidic byproducts that reduce intestinal pH and create an adverse environment for the growth of Enterobacteriaceae, which are known to encode antibiotic resistance genes (ARGs).
Additionally, HMOs function as decoy receptors for enteric pathogens, inhibiting their adherence to the intestinal mucosa and lowering inflammation in the gut that promotes the colonization of pathogens and the transmission of ARGs. HMOs’ ability to reduce gastrointestinal inflammation is crucial in preventing harmful AMR pathogen growth blooms.

Lactoferrin and Antimicrobial Proteins
High levels of lactoferrin, an iron-binding protein found in breast milk, particularly colostrum, have potent antibacterial qualities. Lactoferrin inhibits the growth of pathogens that need iron for proliferation by sequestering iron. Antibiotic-resistant strains of Salmonella, Shigella, and Escherichia coli are among the bacterial pathogens whose pathogenicity and epithelial adhesion are hindered by it. Lactoferrin supplementation has been demonstrated in recent research to shorten infants’ diarrheal sickness duration and lower the risk of newborn sepsis. A healthy intestinal mucus layer is developed and pathogen attachment to the intestinal lumen is prevented by other antimicrobial proteins found in breast milk, notably β-casein and glycosylated proteins like MUC1 and MUC4. This layer shields the intestinal epithelium from harm caused by pathogens and provides support for pathogen clearance, crucial in preventing AMR pathogen establishment.
Extracellular Vesicles (EVs) and MicroRNA (miRNA)Human milk contains extracellular vesicles (EVs), especially exosomes, which are involved in the regulation of immunological response and gut maturation in infants. As the immune system develops, these microvesicles assist prevent enteric infection by delivering maternal-origin microRNAs (miRNAs) to the infant’s intestinal cells. EVs improve gut barrier function and lower the chance of AMR pathogen colonization by promoting intestinal epithelial cell proliferation and providing oxidative stress protection.

Breastfeeding’s Protective Effects Against AMR
Breastfeeding reduces early-life exposures to antibiotics, which are often prescribed to treat infections that can otherwise be managed or prevented through breastfeeding. Another defense against food- and water-borne AMR bacteria is breastfeeding. Formula feeding increases the risk of exposure to contaminated water and feeding bottles, potentially introducing ARG-carrying pathogens like Staphylococcus aureus, Klebsiella pneumoniae, and Clostridioides difficile into the infant gut. By reducing these exposures and promoting the development of a healthy gut microbiota, exclusive breastfeeding improves colonization resistance against infections.

Microbiota in Human Milk around 10^6 bacteria/mL are found in breast milk, which continuously seeds the baby’s stomach with commensal and possibly probiotic bacteria. Among the dominant genera found by 16S rRNA sequencing are Streptococcus and Staphylococcus. These bacteria improve the function of the intestinal barrier and stop pathogen translocation by producing mucin, producing antimicrobial chemicals, and competitively excluding pathogens. Pathogenic bacteria, including multidrug-resistant E. coli, are inhibited by strains such as Lactobacillus rhamnosus, which was isolated from human milk. The stability of maternal-origin bacteria in the infant gut suggests that modulating the maternal gut microbiome during pregnancy and lactation could positively impact infant gut health and resilience against AMR pathogens.
Breast milk, nature’s elixir, fortifies our youngest against the silent threat of antimicrobial resistance, weaving a shield of bioactive brilliance around them. Embracing breastfeeding isn’t just nurturing; it’s a powerful stand against the rising tide of antibiotic-resistant pathogens.

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