Enterococcus VanB Resistance Enables Microbiome Persistence and Infection Original paper
Researched by:
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Divine Aleru
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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.
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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.
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Divine Aleru
Read More
Researched by:
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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 studied?
This multicenter study evaluated the performance of antimicrobial susceptibility testing methods, including EUCAST disk diffusion, CLSI agar screening, and automated systems, to detect VanB-type vancomycin-resistant Enterococcus faecalis and Enterococcus faecium. The study compared detection accuracy across clinical microbiology laboratories using standardized and automated diagnostic approaches. Researchers analyzed detection sensitivity, specificity, and error rates to determine how reliably these methods identify microbiome-derived Enterococcus strains with low and medium vancomycin resistance.
Who was studied?
The study examined 30 microbiome-derived and clinical isolates of Enterococcus faecalis and Enterococcus faecium, including 27 vancomycin-resistant strains and 3 susceptible controls. These isolates originated from human microbiomes, bloodstream infections, and hospital environments across Norway, Sweden, Australia, and the United States. Many strains belonged to high-risk hospital-adapted clonal lineages and expressed diverse VanB resistance phenotypes and resistance levels relevant to microbiome colonization and infection.
What were the most important findings?
VanB-type Enterococcus faecalis and Enterococcus faecium demonstrated variable and inducible vancomycin resistance, allowing microbiome persistence and infection risk. Major microbial associations included increased abundance of VanB-positive Enterococcus strains in hospital microbiomes and bloodstream infections. The EUCAST disk diffusion and CLSI agar screening methods showed high sensitivity of 0.93 and specificity of up to 0.98, confirming reliable detection of resistant microbiome strains. Automated systems performed worse, with sensitivity as low as 0.87, increasing the risk of undetected resistant microbiome populations. Resistance expression varied widely, with vancomycin minimum inhibitory concentrations ranging from 4 to 1,024 mg/L, demonstrating adaptive resistance and microbiome persistence. Low-level resistant Enterococcus strains were more difficult to detect, increasing the risk of microbiome-driven infection progression and treatment failure. High-risk clonal lineages carrying VanB resistance genes showed increased survival, microbiome colonization, and resistance dissemination.
What are the greatest implications of this study?
This study showed that VanB-positive Enterococcus expansion represents a microbiome resistance signature associated with infection risk and treatment failure. Accurate detection is essential to identify resistant microbiome populations and prevent infection progression. These findings confirm that microbiome Enterococcus resistance contributes to persistent colonization and clinical infection.
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.