Abstract
Abstract
The increasing global burden of antimicrobial resistance (AMR) necessitates the exploration of unconventional microbial niches for novel bioactive compounds. Simultaneously, it is also necessary to evaluate their role in the dissemination of resistant bacteria through the food chain. Endophytic bacteria inhabiting edible plant tissues represent a largely underexplored interface between environmental microbiota and human exposure. In this exploratory study, endophytic bacteria were isolated from fresh rhizomes of
Zingiber officinale
(ginger),
Curcuma longa
(turmeric), and
Raphanus sativus
(white radish), and characterized for their antimicrobial activity and antibiotic resistance profiles. A total of 24 endophytic bacterial isolates were isolated from fresh rhizomes of turmeric, ginger and white radish using tissue segmentation method. Among them, eight isolates (33.33%) exhibited weak to strong inhibitory activity against multidrug-resistant clinical pathogens, including
Escherichia coli
,
Escherichia fergusonii
,
Shigella spp.
,
Staphylococcus aureus
, and
Bacillus cereus
. Molecular identification based on 16S rRNA gene sequencing revealed that the isolate RD-1(b) was affiliated with
Burkholderia contaminans
and TM-4(b) and RD-2(c) with
Enterobacter cloacae
. Crude extracellular metabolites extracted from the RD-1(b) retained broad-spectrum antibacterial activity. Notably, these isolates demonstrated resistance to multiple antibiotics, including β-lactams, macrolides, and tetracyclines, while remaining susceptible to selected agents such as ciprofloxacin and cotrimoxazole. The coexistence of antimicrobial activity and multidrug resistance within endophytic bacteria highlights their dual role as both potential sources of bioactive metabolites and reservoirs of AMR determinants. Given that these rhizomes are commonly consumed raw or minimally processed, the presence of such bacteria potentially raises food safety concerns. The possible beneficial role of these endophytes should also be explored.