The healthy human gut can take it all: vancomycin-variable, linezolid-resistant strains and specific bacteriocin-species interplay in Enterococcus spp.

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Almeida-Santos, AC (Author) Other; Duarte, B (Author) Other; Tedim, AP (Author) Other; Teixeira, MJ (Author) Other; Prata, JC (Author) Other; Azevedo, RMS (Author) Other; Novais, Carla (Author) FFUP; Peixe, L (Author) Other; Freitas, AR (Author) Other

Journal

Title: Applied and Environmental Microbiology

ISSN: 0099-2240

Publisher: American Society for Microbiology

Indexing

ISI Web of Knowledge - 0 Citations

Other information

Authenticus ID: P-017-KV3

DOI: 10.1128/aem.01699-24

Abstract (EN): Enterococcus spp. are opportunistic human pathogens colonizing the human gut and a significant reservoir for the continuous adaptation of hospital clones. However, studies on the features of enterococci species co-colonizing healthy individuals are scarce. We investigated the prevalence, antibiotic resistance, and bacteriocin profiles of Enterococcus species in fecal samples from healthy adults in Portugal using culture-based methods, WGS, and bacteriocin inhibition assays. Results were compared with data from a 2001 study in the same region. Enterococcus spp. (n = 315; 24% MDR) were recovered from all volunteers. Enterococcus lactis was the prevalent species (75%), followed by Enterococcus faecalis (65%) and Enterococcus faecium (47%). E. lactis prevalence increased 2.5-fold since 2001. Linezolid resistance genes (optrA/poxtA) were detected in E. faecium and Enterococcus thailandicus isolates, while a vancomycin-variable E. faecium was also identified. Virulence and plasmid profiles were diverse across species, with evidence of exchange of virulence markers and plasmid replicons between E. faecium and E. lactis. Bacteriocin gene repertoires were extensive and species-specific. Higher numbers of bacteriocin genes were associated with stronger inhibition profiles, and 25% of E. faecium and E. lactis isolates were capable of inhibiting relevant VRE clones. This study unveils the co-occurrence and ecological dynamics of Enterococcus species in the healthy human gut, reinforcing its role as a reservoir for key antibiotic resistance genes and potentially pathogenic strains. The shift toward E. lactis prevalence and the detection of linezolid resistance genes in healthy individuals underscore the need for ongoing surveillance of the gut microbiome to guide public health strategies and antibiotic stewardship efforts.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 21