Houyem Elghaieb1, Ana P Tedim2,3, Mohamed S Abbassi1, Carla Novais2, Bárbara Duarte2,4, Abdennaceur Hassen5, Luísa Peixe2, Ana R Freitas2. 1. Université de Tunis El Manar, Institut de la Recherche Vétérinaire de Tunisie, 20 rue Jebel Lakhdhar, Bab Saadoun, Tunis, Tunisia. 2. UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal. 3. Grupo de Investigación Biomédica en Sepsis - BioSepsis, Hospital Universitario Río Hortega, Instituto de Investigación Biomédica de Salamanca (IBSAL), Valladollid, Spain. 4. Departamento de Ciências Biológicas, Unidade de Análises Clínicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal. 5. Laboratoire de Traitement des Eaux Usées, Centre des Recherches et des Technologies des Eaux (CERTE), Technopole Borj Cédria, Soliman, Tunisia.
Abstract
OBJECTIVES: Increasing numbers of linezolid-resistant Enterococcus carrying optrA are being reported across different niches worldwide. We aimed to characterize the first optrA-carrying Enterococcus faecalis obtained from food-producing animals and retail meat samples in Tunisia. METHODS: Seven optrA-carrying E. faecalis obtained from chicken faeces (n=3, August 2017) and retail chicken meat (n=4, August 2017) in Tunisia were analysed. Antimicrobial susceptibility was determined by disc diffusion, broth microdilution and Etest against 13 antibiotics, linezolid and tedizolid, respectively (EUCAST/CLSI). optrA stability (∼600 bacterial generations), transfer (filter mating) and location (S1-PFGE/hybridization) were characterized. WGS (Illumina-HiSeq) was done for four representatives that were analysed through in silico and genomic mapping tools. RESULTS: Four MDR clones carrying different virulence genes were identified in chicken faeces (ST476) and retail meat (the same ST476 clone plus ST21 and ST859) samples. MICs of linezolid and tedizolid were stably maintained at 8 and 1-2 mg/L, respectively. optrA was located in the same transferable chromosomal Tn6674-like element in ST476 and ST21 clones, similar to isolates from pigs in Malaysia and humans in China. ST859 carried a non-conjugative plasmid of ∼40 kb with an impB-fexA-optrA segment, similar to plasmids from pigs and humans in China. CONCLUSIONS: The same chromosomal and transferable Tn6674-like element was identified in different E. faecalis clones from humans and animals. The finding of retail meat contaminated with the same linezolid-resistant E. faecalis strain obtained from a food-producing animal highlights the potential role of the food chain in the worrisome dissemination of optrA that can be stably maintained without selective pressure over generations.
OBJECTIVES: Increasing numbers of linezolid-resistant Enterococcus carrying optrA are being reported across different niches worldwide. We aimed to characterize the first optrA-carrying Enterococcus faecalis obtained from food-producing animals and retail meat samples in Tunisia. METHODS: Seven optrA-carrying E. faecalis obtained from chicken faeces (n=3, August 2017) and retail chicken meat (n=4, August 2017) in Tunisia were analysed. Antimicrobial susceptibility was determined by disc diffusion, broth microdilution and Etest against 13 antibiotics, linezolid and tedizolid, respectively (EUCAST/CLSI). optrA stability (∼600 bacterial generations), transfer (filter mating) and location (S1-PFGE/hybridization) were characterized. WGS (Illumina-HiSeq) was done for four representatives that were analysed through in silico and genomic mapping tools. RESULTS: Four MDR clones carrying different virulence genes were identified in chicken faeces (ST476) and retail meat (the same ST476 clone plus ST21 and ST859) samples. MICs of linezolid and tedizolid were stably maintained at 8 and 1-2 mg/L, respectively. optrA was located in the same transferable chromosomal Tn6674-like element in ST476 and ST21 clones, similar to isolates from pigs in Malaysia and humans in China. ST859 carried a non-conjugative plasmid of ∼40 kb with an impB-fexA-optrA segment, similar to plasmids from pigs and humans in China. CONCLUSIONS: The same chromosomal and transferable Tn6674-like element was identified in different E. faecalis clones from humans and animals. The finding of retail meat contaminated with the same linezolid-resistant E. faecalis strain obtained from a food-producing animal highlights the potential role of the food chain in the worrisome dissemination of optrA that can be stably maintained without selective pressure over generations.
Authors: Lara M Almeida; François Lebreton; Anthony Gaca; Paulo M Bispo; Jose T Saavedra; Rodrigo N Calumby; Luciano M Grillo; Ticiano G Nascimento; Pedro H Filsner; Andrea M Moreno; Michael S Gilmore Journal: Antimicrob Agents Chemother Date: 2020-05-21 Impact factor: 5.191
Authors: Stefan Schwarz; Wanjiang Zhang; Xiang-Dang Du; Henrike Krüger; Andrea T Feßler; Shizhen Ma; Yao Zhu; Congming Wu; Jianzhong Shen; Yang Wang Journal: Clin Microbiol Rev Date: 2021-06-02 Impact factor: 50.129