High-Resolution Genotyping Unveils Identical Ampicillin-Resistant Strains in Different Sources and Countries: A One Health Approach.

Multidrug-resistant (MDR) () infections continue to increase worldwide, although epidemiological studies remain scarce in lower middle-income countries. We aimed to explore which strains circulate in causing human infections in Tunisian healthcare institutions in order to compare them with strains from non-human sources of the same country and finally to position them within the global epidemiology by genomic analysis. Antibiotic susceptibility testing was performed and transfer of vancomycin- and ampicillin- resistance was performed by conjugation. WGS-Illumina was performed on Tunisian strains, and these genomes were compared with genomes from other regions present in the GenBank/NCBI database ( = 10,701 genomes available May 2021). A comparison of phenotypes with those predicted by the recent ResFinder 4.1-CGE webtool unveiled a concordance of 88%, with discordant cases being discussed. cgMLST revealed three clusters [ST18/CT222 ( = 13), ST17/CT948 strains ( = 6), and ST203/CT184 ( = 3)], including isolates from clinical, healthy-human, retail meat, and/or environmental sources in different countries over large time spans (10-12 years). Isolates within each cluster showed similar antibiotic resistance, bacteriocin, and virulence genetic patterns. -AmpR was transferred by VanA-AmpR-ST80 (clinical) and AmpR-ST17- (bovine meat). Identical chromosomal -platforms carrying metabolic/virulence genes were identified between ST17/ST18 strains of clinical, farm animal, and retail meat sources. The overall results emphasize the role of high-resolution genotyping as provided by WGS in depicting the dispersal of MDR- strains carrying relevant adaptive traits across different hosts/regions and the need of a One Health task force to curtail their spread.