Deciphering the Structural Diversity and Classification of the Mobile Tigecycline Resistance Gene tet (X)-Bearing Plasmidome among Bacteria

Tigecycline is an expanded-spectrum tetracycline used as a last-resort antimicrobial for treating infections caused by superbugs such as carbapenemase-producing or colistin-resistant pathogens. Emergence of the plasmid-mediated mobile tigecycline resistance gene tet (X4) created a great public health concern. However, the diversity of tet (X4)-bearing plasmids and bacteria remains largely uninvestigated. To cover this knowledge gap, we comprehensively identified and characterized the tet (X)-bearing plasmidome in different sources using advanced sequencing technologies for the first time. The huge diversity of tet (X4)-bearing mobile elements demonstrates the high level of transmissibility of the tet (X4) gene among bacteria. It is crucial to enhance stringent surveillance of tet (X) genes in animal and human pathogens globally.