Emergence of tet(X4)-positive Klebsiella isolates from aquatic products in Hainan, China.

The emergence of Klebsiella pneumoniae species complex (KpSC) with tet(X4) in aquatic products poses a public health risk. Among 442 aquatic products sampled in Hainan, 14 tet(X4)-positive isolates were identified with multidrug-resistant profiles. IncFII(pCRY)_v, a previously uncharacterized plasmid, emerged as the dominant tet(X4) carrier in this study, transferable by conjugation and widely present in KpSC, and particularly prevalent among clinical isolates. These findings call for One Health strategies to monitor and mitigate antimicrobial resistance in aquaculture.