Rahisuddin Khan, Shirjeel Ahmad Siddiqui, Vishnu AL and Iqbal Ahmad*

Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh-202002, Uttar Pradesh, India

*Corresponding Author: Iqbal Ahmad, Professor, Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, 202002, UP, India.

Received: May 19, 2026; Published: July 03, 2026

Abstract

Antimicrobial resistance (AMR) is a major global health concern, and wastewater environments serve as important reservoirs for the dissemination of multidrug-resistant (MDR) bacteria. In this study, 70 Gram-negative bacterial isolates were obtained from four wastewater sites in Aligarh and tentatively identified as Escherichia coli, Enterobacter spp., Citrobacter spp., Proteus spp., Pseudomonas spp., Salmonella spp., Shigella spp., Klebsiella spp., and Serratia spp. Antibiotic susceptibility testing revealed the highest resistance to ampicillin and amoxicillin (100%), rifampicin (82%), erythromycin (73%), and nalidixic acid (58%), while lower resistance was observed against chloramphenicol (18%), nitrofurantoin (10%), and aminoglycosides (1.5-7%). β-lactamase production was detected in 24 isolates, and 10 were confirmed as ESBL producers by PDCT. Biofilm analysis showed strong biofilm formation in 32.48% of isolates. The antibacterial and antibiofilm activities of nine medicinal plant extracts were evaluated against strong biofilm- forming strains and standard cultures (Escherichia coli ATCC 25922, Staphylococcus aureus MTCC 737, and Pseudomonas aeruginosa PAO1). Among the nine medicinal extracts, Carum copticum and Terminalia chebula exhibited activity against all standard cultures and E. coli isolates. Based on initial screening, Carum copticum was selected for detailed study against a strong biofilm-forming E. coli isolate (SAS5). Showing a dose-dependent reduction in biofilm formation, with maximum inhibition observed at MIC/2 concentration (69.3%) of Carum copticum. Scanning Electron Microscopy analysis revealed significant biofilm inhibition by Carum copticum extract on the SAS5 strain compared to the control. The study highlights wastewater as a significant source of MDR bacteria and demonstrates the potential of medicinal plant extracts as alternative antibacterial and antibiofilm agents against drug-resistant pathogens.

Keywords: Antimicrobial Resistance; ESBL; Plant Extracts and Antibiofilm Agent

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Citation

Citation: Iqbal Ahmad., et al. “Elucidating the Antibacterial and Antibiofilm Efficacy of Carum copticum Against Multidrug-Resistant Bacteria of Wastewa- ter Origin". Acta Scientific Microbiology 9.7 (2026): 29-43.

Copyright

Copyright: © 2026 Iqbal Ahmad., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.