Whole-Genome Insights Into Tigecycline-ResistantSpp. Harboring Colistin Resistance Gene From Food Animals in Türkiye.

Abstract

Antimicrobial-resistant (AMR)spp., the common agents of nosocomial infections, are on the rise and becoming increasingly dangerous, with tigecycline-resistant strains posing a serious clinical threat. This study aimed to characterize isolated tigecycline-resistant strains from Türkiye by using whole-genome sequencing (WGS). The genomes of 40 strains, recovered from turkey caecum samples ( = 23,), chicken caecum samples ( = 8,; = 2,), and chicken meat samples ( = 7,), were determined. Additionally, Oxford Nanopore Sequencing was conducted on subsets (-8-positive, = 9) to characterize the plasmids responsible for colistin resistance spread. Sequence analysis revealed that allharbored the(A) gene without detectable mutations, whereas several alterations were detected in thegene. Additionally, other tetracycline-encoding genes were also detected in few isolates, including(B),(D),(J), and(M). Genomic analysis revealed various AMR genes, including the plasmid-mediated colistin resistance gene-8, for which hybrid assemblies confirmed the localization on IncF group plasmids associated with IS. Conjugation assay showed the transferability of-8 in isolates (8/9) torecipient strains. WGS analysis also revealed 11 different sequence types (STs), with ST37 appearing as the predominant lineage among both tigecycline- and colistin-resistant isolates. Phylogenetic comparison with previously sequenced isolates showed close genetic relatedness between certain isolates and international clones. To our knowledge, this is the first report of-8 instrains from food animals in Türkiye, highlighting a potential risk for transmission of last-resort antimicrobial resistance genes to humans. Hence, continuous genomic surveillance is urgently needed to monitor the spread of these resistance determinants within the One Health perspective.