Linezolid-resistant (Tn 6246 :: fexB - poxtA ) Enterococcus faecium strains colonizing humans and bovines on different continents: similarity without epidemiological link
[1];
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal, Grupo de Investigación Biomédica en Sepsis – BioSepsis, Hospital Universitario Rio Hortega/Instituto de Investigación Biomédica de Salamanca (IBSAL), Valladolid/Salamanca, Spain
- UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal, Departamento de Ciências Biológicas, Unidade de Análises Clínicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
- Université de Tunis El Manar, Institut de la Recherche Vétérinaire de Tunisie, 20 rue Jebel Lakhdhar, Bab Saadoun, Tunis, Tunisia
- Laboratoire de Traitement des Eaux Usées, Centre des Recherches et des Technologies des Eaux (CERTE), Technopole Borj Cédria, Soliman, Tunisia
- Serviço de Patologia Clínica-Microbiologia, Hospital Pedro Hispano, Matosinhos, Portugal
Abstract Objectives poxtA is the most recently described gene conferring acquired resistance to linezolid, a relevant antibiotic for treating enterococcal infections. We retrospectively screened for poxtA in diverse enterococci and aimed to characterize its genetic/genomic contexts. Methods poxtA was screened by PCR in 812 enterococci from 458 samples (hospitals/healthy humans/wastewater/animals/retail food) obtained in Portugal/Angola/Tunisia (1996–2019). Antimicrobial susceptibility testing was performed for 13 antibiotics (EUCAST/CLSI). poxtA stability (∼500 generations), transfer (filter mating), clonality (SmaI-PFGE) and location (S1-PFGE/hybridization) were tested. WGS (Illumina-HiSeq) was performed for clonal representatives. Results poxtA was detected in Enterococcus faecium from six samples (1.3%): a healthy human (rectal swab) in Porto, Portugal (ST32/2001); four farm cows (milk) in Mateur, Tunisia (ST1058/2015); and a hospitalized patient (faeces) in Matosinhos, Portugal (ST1058/2015). All expressed resistance to linezolid (MIC = 8 mg/L), chloramphenicol, tetracycline and erythromycin, with variable resistance to ciprofloxacin and streptomycin. ST1058-poxtA-carrying isolates from Tunisia and Portugal differed by two SNPs and had similar plasmid content. poxtA, located in an IS1216-flanked Tn6246-like element, co-hybridized with fexB on one or more plasmids per isolate (one to three plasmids of 30–100 kb), was stable after several generations and transferred only from ST1058. ST1058 strains carried resistance/virulence genes (Efmqnr/acm) possibly induced under selective quinolone treatment. Conclusions poxtA has been circulating in Portugal since at least 2001, corresponding to the oldest description worldwide to date. We also extend the reservoir of poxtA to bovines. The similar linezolid-resistant poxtA-carrying strains colonizing humans and livestock on different continents, and without a noticeable relationship, suggests a recent transmission event or convergent evolution of E. faecium populations in different hosts and geographic regions.
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE), Nuclear Fuel Cycle and Supply Chain
- OSTI ID:
- 1650207
- Journal Information:
- Journal of Antimicrobial Chemotherapy, Journal Name: Journal of Antimicrobial Chemotherapy Journal Issue: 9 Vol. 75; ISSN 0305-7453
- Publisher:
- Oxford University PressCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
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