Novel Plasmid-Mediated tet(X5) Gene Conferring Resistance to Tigecycline, Eravacycline, and Omadacycline in a Clinical Acinetobacter baumannii Isolate

Antimicrob Agents Chemother. 2019 Dec 20;64(1):e01326-19. doi: 10.1128/AAC.01326-19. Print 2019 Dec 20.


A novel, plasmid-mediated, high-level tigecycline resistance tet(X) gene variant, tet(X5), was detected in a clinical Acinetobacter baumannii isolate from China in 2017. Tet(X5) shows 84.5% and 90.5% amino acid identity to Tet(X3) and Tet(X4), respectively, with similar binding sites and a comparable affinity for tetracyclines. The tet(X5)-containing plasmid could only be transferred to A. baumannii via electrotransformation. This report follows the recent study describing the identification of tet(X3) and tet(X4).

Keywords: Acinetobacter baumannii; tet(X5); tigecycline.

Publication types

  • Research Support, Non-U.S. Gov't