Yu Rui, Zhang Yue, Xu Yindi, Schwarz Stefan, Li Xin-Sheng, Shang Yan-Hong, Du Xiang-Dang
College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, China.
Institute for Animal Husbandry and Veterinary Research, Henan Academy of Agricultural Sciences, Zhengzhou, China.
Front Vet Sci. 2021 Aug 19;8:709327. doi: 10.3389/fvets.2021.709327. eCollection 2021.
The aim of this study was to gain insight into the resistance determinants conferring resistance to tigecycline in (.) and to investigate the genetic elements involved in their horizontal transfer. A total of 31 tetracycline-resistant isolates were screened for tigecycline resistance by broth microdilution. isolate SC128 was subjected to whole genome sequencing with particular reference to resistance determinants involved in tigecycline resistance. Transferability of genomic island (GI) GISC128 was investigated by transformation. The roles of (L) or (M) in contributing to tigecycline resistance in were confirmed by transformation using different (L)- or (M)-carrying constructs. Only SC128 showed a tigecycline resistance phenotype. A (L)-(M) and co-carrying GISC128 was identified in this isolate. After transfer of the novel GI into a susceptible recipient, this recipient showed the same tigecycline resistance phenotype. Further transfer experiments with specific (L)- or (M)-carrying constructs confirmed that only (M), but not (L), contributes to resistance to tigecycline. Protein sequence analysis identified a Tet(M) variant, which is responsible for tigecycline resistance in SC128. It displayed 94.8% amino acid identity with the reference Tet(M) of DO plasmid 1. To the best of our knowledge, this is the first time that a (M) variant conferring resistance to tigecycline was identified in . Its location on a GI will accelerate its transmission among the population.
本研究的目的是深入了解[具体研究对象]中赋予对替加环素耐药性的耐药决定因素，并研究参与其水平转移的遗传元件。通过肉汤微量稀释法对总共31株四环素耐药菌株进行替加环素耐药性筛选。菌株SC128进行了全基因组测序，特别关注与替加环素耐药性相关的耐药决定因素。通过转化研究基因组岛（GI）GISC128的可转移性。使用携带不同（L）或（M）的构建体进行转化，证实了（L）或（M）在[具体研究对象]对替加环素耐药性中的作用。只有菌株SC128表现出替加环素耐药表型。在该菌株中鉴定出携带GISC128的（L）-（M）和[具体内容]。将新的基因组岛转移到敏感受体后，该受体表现出相同的替加环素耐药表型。使用携带特定（L）或（M）的构建体进行的进一步转移实验证实，只有（M）而非（L）导致对替加环素的耐药性。蛋白质序列分析鉴定出一种Tet（M）变体，它是[具体研究对象]SC128中替加环素耐药性的原因。它与DO质粒1的参考Tet（M）具有94.8%的氨基酸同一性。据我们所知，这是首次在[具体研究对象]中鉴定出赋予对替加环素耐药性的（M）变体。它在基因组岛上的位置将加速其在[具体研究对象]群体中的传播。
