Wenbo Hao1, Xinxin Shan1, Dexi Li1, Stefan Schwarz2, Su-Mei Zhang1, Xin-Sheng Li1, Xiang-Dang Du1. 1. College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou, PR China. 2. Institute of Microbiology and Epizootics, Centre for Infection Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
Abstract
OBJECTIVES: To investigate the presence and transferability of the poxtA gene and identify the genetic context of poxtA in two enterococcal plasmids from swine. METHODS: MICs were determined by broth microdilution. A total of 114 porcine enterococci with florfenicol MICs of ≥16 mg/L were screened for the presence of the poxtA gene by PCR. Transferability of poxtA was investigated by conjugation and transformation. The poxtA-carrying plasmids were completely sequenced using the Illumina Miseq and PacBio RSII platform. The presence of circular intermediates was examined by inverse PCR. RESULTS: The poxtA gene was present in 57.9% (66/114) of the florfenicol-resistant porcine enterococci. Two poxtA-carrying plasmids, pE035 and pE076, were identified. The conjugative 121524 bp plasmid pE035 carried poxtA and optrA along with the resistance genes erm(A), erm(B), aac(A)-aph(D), lnu(G), fexB, dfrG and bcrABDR. Three mobile elements, comprising a mobile dfrG locus, a mobile bcrABDR locus and an unconventional circularizable structure containing aac(A)-aph(D), were located on this plasmid and all proved to be active by inverse PCR. The non-conjugative 19832 bp plasmid pE076 only carried poxtA and fexB. After transfer, both the transconjugant and the transformant displayed elevated MICs of the respective antimicrobial agents. CONCLUSIONS: To the best of our knowledge, this is the first report of the co-location of the oxazolidinone resistance genes poxtA and optrA on a conjugative multiresistance plasmid from a porcine enterococcal strain. In addition, the presence of three mobile elements in such a plasmid will aid in the persistence and dissemination of poxtA and optrA among enterococci.
OBJECTIVES: To investigate the presence and transferability of the poxtA gene and identify the genetic context of poxtA in two enterococcal plasmids from swine. METHODS: MICs were determined by broth microdilution. A total of 114 porcine enterococci with florfenicol MICs of ≥16 mg/L were screened for the presence of the poxtA gene by PCR. Transferability of poxtA was investigated by conjugation and transformation. The poxtA-carrying plasmids were completely sequenced using the Illumina Miseq and PacBio RSII platform. The presence of circular intermediates was examined by inverse PCR. RESULTS: The poxtA gene was present in 57.9% (66/114) of the florfenicol-resistant porcine enterococci. Two poxtA-carrying plasmids, pE035 and pE076, were identified. The conjugative 121524 bp plasmid pE035 carried poxtA and optrA along with the resistance genes erm(A), erm(B), aac(A)-aph(D), lnu(G), fexB, dfrG and bcrABDR. Three mobile elements, comprising a mobile dfrG locus, a mobile bcrABDR locus and an unconventional circularizable structure containing aac(A)-aph(D), were located on this plasmid and all proved to be active by inverse PCR. The non-conjugative 19832 bp plasmid pE076 only carried poxtA and fexB. After transfer, both the transconjugant and the transformant displayed elevated MICs of the respective antimicrobial agents. CONCLUSIONS: To the best of our knowledge, this is the first report of the co-location of the oxazolidinone resistance genes poxtA and optrA on a conjugative multiresistance plasmid from a porcine enterococcal strain. In addition, the presence of three mobile elements in such a plasmid will aid in the persistence and dissemination of poxtA and optrA among enterococci.
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: Cecilia G Carvalhaes; Helio S Sader; Robert K Flamm; Jennifer M Streit; Rodrigo E Mendes Journal: Antimicrob Agents Chemother Date: 2020-03-24 Impact factor: 5.191
Authors: Corentin R Fostier; Laura Monlezun; Farès Ousalem; Shikha Singh; John F Hunt; Grégory Boël Journal: FEBS Lett Date: 2020-12-04 Impact factor: 4.124
Authors: Sarah A Egan; Anna C Shore; Brian O'Connell; Grainne I Brennan; David C Coleman Journal: J Antimicrob Chemother Date: 2020-07-01 Impact factor: 5.790
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