First report of regional spreading and long-term inhabitation of VanD-type vancomycin-resistant Enterococcus faecalis clinical strains: A proposal of new classification of vanD gene subtypes
Objective: VanD-type vancomycin resistance is rarely reported in Enterococcus faecalis. This study aimed to characterise five VanD-type vancomycin-resistant E. faecalis strains isolated over 8 years from three hospitals in a local city in Japan, with a focus on resistance mechanisms, genetic backgro...
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| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-09-01
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| Series: | Journal of Global Antimicrobial Resistance |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2213716525001791 |
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| Summary: | Objective: VanD-type vancomycin resistance is rarely reported in Enterococcus faecalis. This study aimed to characterise five VanD-type vancomycin-resistant E. faecalis strains isolated over 8 years from three hospitals in a local city in Japan, with a focus on resistance mechanisms, genetic background, and phylogenetic classification. Methods: Five E. faecalis strains (SVR2085, SVR2281, SVR2330, SVR2331, and SVR2332) were analysed using antimicrobial susceptibility testing, plasmid profiling, and whole-genome sequencing. Genomic islands (GIs) containing vanD gene clusters were characterised. Core GI gene and core genome phylogenies were compared, and vanD homologues were classified using public database sequences. Results: All strains exhibited high-level resistance to vancomycin (MIC >1024–64 mg/L), multiple drug resistance, and carried pheromone-responsive plasmids encoding bacteriocin 41 as a colonisation factor. Four strains shared nearly identical GIs (126–185 kbp), while SVR2330 had a structurally distinct GI. Phylogenetic analysis showed that the four similar strains formed a single cluster, suggesting a common ancestor, whereas SVR2330 was divergent. Comparative analysis of 37 vanD homologues revealed high genetic diversity, allowing classification into three subgroups – vanD(I), vanD(II), and vanD(III). The vanD of SVR2330 was assigned as vanD(III)-4, and the others as vanD(II)-6, -11, -15, and -17. Conclusions: This study proposes a new classification scheme for diverse vanD genes and provides the first evidence of the regional spread and long-term persistence of VanD-type vancomycin-resistant E. faecalis in Japan. |
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| ISSN: | 2213-7165 |