Antimicrobial Efficacy of Green Synthesized Nanosilver with Entrapped Cinnamaldehyde against Multi-Drug-Resistant Enteroaggregative <i>Escherichia coli</i> in <i>Galleria mellonella</i>
Vemula Prasastha Ram,
Jyothsna Yasur,
Padikkamannil Abishad,
Varsha Unni,
Diksha Purushottam Gourkhede,
Maria Anto Dani Nishanth,
Pollumahanti Niveditha,
Jess Vergis,
Satya Veer Singh Malik,
Byrappa Kullaiah,
Nitin Vasantrao Kurkure,
Chatragadda Ramesh,
Laurent Dufossé,
Deepak B. Rawool,
Sukhadeo B. Barbuddhe
Affiliations
Vemula Prasastha Ram
Division of Veterinary Public Health, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243122, India
Jyothsna Yasur
ICAR-National Research Centre on Meat, Hyderabad 500092, India
Padikkamannil Abishad
Department of Veterinary Public Health, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University, Pookode 673576, India
Varsha Unni
Department of Veterinary Public Health, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University, Pookode 673576, India
Diksha Purushottam Gourkhede
Division of Veterinary Public Health, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243122, India
Maria Anto Dani Nishanth
Division of Veterinary Public Health, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243122, India
Pollumahanti Niveditha
ICAR-National Research Centre on Meat, Hyderabad 500092, India
Jess Vergis
Department of Veterinary Public Health, College of Veterinary and Animal Sciences, Pookode, Kerala Veterinary and Animal Sciences University, Pookode 673576, India
Satya Veer Singh Malik
Division of Veterinary Public Health, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243122, India
Byrappa Kullaiah
Centre for Research and Innovations, BGS Institute of Technology, Adichunchanagiri University, Mandya 571448, India
Nitin Vasantrao Kurkure
Department of Veterinary Pathology, Nagpur Veterinary College, Nagpur 440006, India
Chatragadda Ramesh
Biological Oceanography Division (BOD), Council of Scientific and Industrial Research, National Institute of Oceanography (CSIR-NIO), Dona Paula 403004, India
Laurent Dufossé
Chemistry and Biotechnology of Natural Products (CHEMBIOPRO Lab), Département Agroalimentaire, Ecole Supérieure d’Ingénieurs Réunion Océan Indien (ESIROI), Université de La Réunion, F-97744 Saint-Denis, France
Deepak B. Rawool
ICAR-National Research Centre on Meat, Hyderabad 500092, India
Sukhadeo B. Barbuddhe
ICAR-National Research Centre on Meat, Hyderabad 500092, India
The global emergence of antimicrobial resistance (AMR) needs no emphasis. In this study, the in vitro stability, safety, and antimicrobial efficacy of nanosilver-entrapped cinnamaldehyde (AgC) against multi-drug-resistant (MDR) strains of enteroaggregative Escherichia coli (EAEC) were investigated. Further, the in vivo antibacterial efficacy of AgC against MDR-EAEC was also assessed in Galleria mellonella larval model. In brief, UV-Vis and Fourier transform infrared (FTIR) spectroscopy confirmed effective entrapment of cinnamaldehyde with nanosilver, and the loading efficiency was estimated to be 29.50 ± 0.56%. The AgC was of crystalline form as determined by the X-ray diffractogram with a mono-dispersed spherical morphology of 9.243 ± 1.83 nm in electron microscopy. AgC exhibited a minimum inhibitory concentration (MIC) of 0.008–0.016 mg/mL and a minimum bactericidal concentration (MBC) of 0.008–0.032 mg/mL against MDR- EAEC strains. Furthermore, AgC was stable (high-end temperatures, proteases, cationic salts, pH, and host sera) and tested safe for sheep erythrocytes as well as secondary cell lines (RAW 264.7 and HEp-2) with no negative effects on the commensal gut lactobacilli. in vitro, time-kill assays revealed that MBC levels of AgC could eliminate MDR-EAEC infection in 120 min. In G. mellonella larvae, AgC (MBC values) increased survival, decreased MDR-EAEC counts (p < 0.001), had an enhanced immunomodulatory effect, and was tested safe to the host. These findings infer that entrapment enhanced the efficacy of cinnamaldehyde and AgNPs, overcoming their limitations when used individually, indicating AgC as a promising alternative antimicrobial candidate. However, further investigation in appropriate animal models is required to declare its application against MDR pathogens.
