Incidental detection and short-read-based whole-genome sequencing of tet(X4)-positive enterobacterales from retail chicken meat in the United Arab Emirates

Tigecycline is one of the remaining treatment options for severe infections caused by multidrug-resistant Enterobacterales. The detection of transferable resistance mediated by the gene tet(X4) in foodborne bacteria is an emerging One Health concern. In this communication, we report the characterization of three tet(X4) -positive Enterobacterales detected in chicken meat in the United Arab Emirates (UAE). The isolates were detected during screening of 315 chilled retail broiler carcasses and were characterized using tigecycline disk-diffusion screening, PCR detection of mobile tigecycline-resistance determinants, EUVSEC3 antimicrobial sensitivity testing, VITEK 2 extended-spectrum beta-lactamases (ESBL) assessment, short-read whole-genome sequencing (WGS), and in silico resistome/plasmidome analysis. The isolates comprised Escherichia coli ST354 (EMC8), E. coli ST1011 (EMC11), and Salmonella enterica serovar Kentucky ST198 (SAL58). The Salmonella / E. coli EUVSEC3 antimicrobial sensitivity testing panel classified all three as tigecycline non-wild-type (1–2 mg/L), as values were slightly above the surveillance threshold (>0.5 mg/L). The E. coli isolates were ESBL-positive by VITEK 2 and non-wild-type to 12/15 antimicrobial agents, whereas SAL58 was ESBL-negative and non-wild-type to 8/15 agents. WGS detected tet(X4) in MOB-suite-predicted plasmid bins: a 25.2-kb AB193 bin in SAL58 that also contained seven other antimicrobial-resistance genes, and AC770 bins in both E. coli isolates carrying tet(X4) as the only detected resistance gene. MOB-suite identified the tet(X4) -bearing bins to be computationally predicted as mobilizable. The National Center for Biotechnology Information (NCBI) Pathogen Detection placed SAL58 within a globally distributed ST198 SNP cluster dominated by clinical isolates, providing genomic context rather than epidemiological linkage. To the best of our knowledge, this is the first report of tet(X4) -positive foodborne bacterial isolates in the UAE. These incidental detections reported in this communication provide an early UAE baseline and support sustained genomic surveillance of transferable tigecycline non-wild-type determinants in poultry meat.