ABSTRACT Consumption of unprocessed plant-based foods may expose consumers to environmental antibiotic-resistant bacteria residing in plants. This study investigates the antimicrobial resistance (AMR) characteristics of endophytic bacteria isolated from selected edible and medicinal plants and to analyze the genomic sequence of the strain exhibiting the highest resistance, with the goal of identifying the underlying antibiotic resistance genes. In this study, 228 bacterial endophytic were isolated obtained from leaves, stems, and roots/rhizomes of Mesosphaerum suaveolens (L.). Kuntze, Azadirachta indica, Zingiber officinale, Allium sativum, and Aloe barbadensis . Twenty isolates displaying Bacillus -like morphological and microscopic characteristics were chosen for in-depth identification. Biochemical profiling combined with 16S rRNA gene sequencing identified them as belonging to the genera Bacillus, Rhizobium, Variovorax, Pseudomonas, and Sphingomonas. Bacillus spp. exhibited a high level of resistance to Amoxyclav (56.25%), Azithromycin (50.00%), and Ceftazidime (43.75%). In addition to Bacillus spp., other bacterial isolates also exhibited resistance to the tested antibiotics. Out of these 20 isolates, one Bacillus subtilis strain ATA1 was resistant to Amoxiclav, Cefepime, Cefpirome, Tetracycline, Co-Trimoxazole, Ciprofloxacin, Erythromycin, and Cefalexin. Whole-genome sequencing (WGS) performed on strain ATA1 resulted in an assembled highly fragmented draft genome size of 4.38 Mb, predicted to encode 4,288 protein-coding genes. The genome of strain ATA1 harbored several AMR genes, including ykkC, mphK, vanT, qacJ, ykkD, vanW, Bcl, vanY, tmrB, vmlR, aadK, qacG, and FosBx1, which mediate resistance via efflux pumps, target bypass/alteration, and enzyme-mediated drug modification. These findings highlight potential health risks associated with the consumption of inadequately processed plants harboring antibiotic-resistant endophytes.
Dhanokar et al. (Fri,) studied this question.