Preliminary view of the global distribution and spread of the tet(X) family of tigecycline resistance genes. (7th August 2020) - Pan, Yu
Abstract: Background: The emergence of plasmid-mediated tet (X3)/ tet (X4) genes is threatening the role of tigecycline as a last-resort antibiotic to treat clinical infections caused by XDR bacteria. Considering the possible public health threat posed by tet (X) and its variants [which we collectively call ' tet (X) genes' in this study], global monitoring and surveillance are urgently required. Objectives: Here we conducted a worldwide survey of the global distribution and spread of tet (X) genes. Methods: We analysed a comprehensive dataset of bacterial genomes in conjunction with surveillance data from our laboratory and the NCBI database, as well as sufficient metadata to characterize the results. Results: The global distribution features of tet (X) genes were revealed. We clustered three types of genetic backbones of tet (X) genes embedded or transferred in bacterial genomes. Our pan-genome analyses revealed a large genetic pool composed of tet (X)-carrying sequences. Moreover, phylogenetic trees of tet (X) genes and tet (X)-like proteins were built. Conclusions: To the best of our knowledge, our results provide the first view of the global distribution of tet (X) genes, demonstrate the features of tet (X)-carrying fragments and highlight the possible evolution of tigecycline-inactivation enzymes in diverse bacterial species and habitats.