Co-occurrence of the tigecycline resistance gene cluster tmexCD3-toprJ1 and verona integron-encoded metallo-β-lactamase (VIM) in a human-derived Pseudomonas sediminis isolate.

UNLABELLED: As the last line of defense against carbapenemase-producing Enterobacterales, the growing prevalence of tigecycline resistance poses a serious challenge to clinical therapy. Although tmexCD-toprJ clusters were initially described in Enterobacterales, increasing reports in non-fermenting gram-negative bacteria, including Pseudomonas species, suggest potential cross-species dissemination (N. Dong, Y. Zeng, Y. Wang, C. Liu, J. Lu, C. Cai, X. Liu, Y. Chen, Y. Wu, Y. Fang, Y. Fu, Y. Hu, H. Zhou, J. Cai, F. Hu, S. Wang, Y. Wang, Y. Wu, G. Chen, Z. Shen, S. Chen, R. Zhang, Lancet Microbe 3:e846-e856, 2022 https://doi.org/10.1016/S2666-5247(22)00221-X). Here, we report a Pseudomonas sediminis which exhibited reduced susceptibility to tigecycline (minimum inhibitory concentration > 8 mg/L) carrying tmexCD3-toprJ1 and blaVIM-2 from a child's intestinal tract. Genomic analysis revealed that the gene cluster is present in different hosts and associated with a complex genetic environment.

IMPORTANCE: Tigecycline is regarded as one of the last options against multidrug-resistant gram-negative bacteria, especially carbapenemase-producing bacteria. Here, we describe a strain of Pseudomonas sediminis (C3-T-78-1) in China carrying tigecycline resistance gene cluster tmexCD3-toprJ1 and carbapenemase resistance blaVIM-2 in a complex gene environment. We highlight that these genes have the potential to disseminate across bacterial hosts and may represent a potential reservoir for antimicrobial resistance dissemination.