Regulation of VanA- and VanB-Type Glycopeptide Resistance in Enterococci Original paper
Researched by:
-
Divine Aleru
ID
Divine Aleru
Read MoreI am a biochemist with a deep curiosity for the human microbiome and how it shapes human health, and I enjoy making microbiome science more accessible through research and writing. With 2 years experience in microbiome research, I have curated microbiome studies, analyzed microbial signatures, and now focus on interventions as a Microbiome Signatures and Interventions Research Coordinator.
-
Microbes
Microbes
Microbes are microscopic organisms living in and on the human body, shaping health through digestion, vitamin production, and immune protection. When microbial balance is disrupted, disease can occur. This guide explains key microbe types—bacteria, viruses, fungi, protozoa, and archaea—plus major pathogenic and beneficial examples.
-
Divine Aleru
Read More
Researched by:
-
Divine Aleru
ID
Divine Aleru
Read More
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Divine Aleru
What was reviewed?
This review examined how Enterococcus faecalis and Enterococcus faecium regulate VanA- and VanB-type glycopeptide resistance, which enables survival during vancomycin and related antibiotic exposure. The authors reviewed molecular, genetic, and microbiological evidence explaining how resistance genes alter peptidoglycan synthesis and how regulatory systems activate resistance in response to antibiotic exposure. The review focused on gene regulation, signal sensing, and adaptive resistance mechanisms that allow Enterococcus to persist in antibiotic-disrupted microbiomes and infection sites.
Who was reviewed?
The review evaluated microbiome-derived and clinical strains of Enterococcus faecalis and Enterococcus faecium carrying VanA and VanB resistance gene clusters. These strains were isolated from human microbiomes and infection sites including bloodstream and cardiac infections. The review examined resistant and susceptible Enterococcus populations to understand how resistance develops, activates, and spreads within microbiome and clinical environments.
What were the most important findings?
VanA and VanB resistance allowed Enterococcus to survive glycopeptide antibiotics by altering cell wall structure and activating resistance genes in response to antibiotic exposure. Major microbial associations included increased abundance and persistence of vancomycin-resistant Enterococcus in antibiotic-exposed microbiomes. Resistance occurred when VanH, VanA, and VanX enzymes replaced the normal D-Ala–D-Ala cell wall structure with D-Ala–D-Lac, reducing antibiotic binding and preventing bacterial killing. This modification reduced glycopeptide binding affinity by up to 1000-fold, allowing survival and microbiome persistence. Regulatory proteins VanS and VanR detected antibiotic exposure and activated resistance gene expression through phosphorylation-dependent signaling. This activation allowed Enterococcus to dynamically respond to antibiotics and rapidly increase resistance gene expression. Resistance expression was inducible, constitutive, or variable depending on mutations and regulatory activity, allowing adaptive survival. Horizontal gene transfer and amplification loops increased resistance gene expression and persistence. These mechanisms enabled resistant Enterococcus strains to dominate microbiomes disrupted by antibiotic treatment and increase infection risk.
What are the greatest implications of this review?
This review showed that glycopeptide resistance enables Enterococcus expansion, microbiome dominance, and infection persistence during antibiotic exposure. VanA and VanB resistance represent critical microbiome signatures associated with antibiotic resistance and infection risk. These mechanisms allow Enterococcus to survive treatment, spread resistance genes, and promote microbiome-driven disease.
Enterococcus faecalis
Enterococcus faecalis is a gut‑adapted, Gram‑positive, non‑spore‑forming facultative anaerobe that becomes an important opportunistic pathogen in healthcare when host barriers are breached or antibiotics select for enterococcal overgrowth. Its clinical impact is driven more by persistence, adhesion, and biofilm biology, quorum‑regulated secreted effectors (fsr‑controlled gelatinase GelE), and high genome plasticity than by a broad repertoire of classical tissue‑destroying toxins. Antimicrobial decision‑making must account for the intrinsic poor activity of cephalosporins, the potential for transferable glycopeptide resistance mediated by van gene clusters, and the need for regimen selection in endocarditis that respects synergy/tolerance and local high‑level aminoglycoside resistance patterns.