PAKISTAN VETERINARY JOURNAL

Pak Vet J, 2026, 46(3) 681-690

Genetic Characterization of Multidrug-Resistant Bacteria and Antibacterial Activity of Alpha-Mangostin and Clove Oil Nanostructured Lipid Carriers in Canine Periodontitis

Gotchagorn Sawatphakdee ¹, Sunchai Payungporn ², Prangwalai Chanchaem ², Jakarwan Yostawonkul ³, Manoj Tukaram Kamble ¹, Sirinun Pisamai Tabtieang ^{4,
5}, Nunthawan Nowwarote ⁶, and Nopadon Pirarat ^{1, *}

¹Center of Excellence in Wildlife, Exotic, and Aquatic Animal Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand; ²Center of Excellence in Systems Microbiology (CESM), Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand; ³National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani 12120, Thailand; ⁴Department of Veterinary Surgery, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand; ⁵Center of Excellence for Companion Animal Cancer, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand; ⁶INSERM UMR1163, Imagine Institute, Universite Paris Cite, Paris 75015, France.

*Corresponding author: nopadonpirarat@gmail.com

Abstract

Canine periodontitis is a prevalent oral disease increasingly complicated by multidrug-resistant (MDR) bacteria, reducing the effectiveness of current antimicrobial therapies and creating treatment challenges. This study evaluated the antimicrobial efficacy of a nanostructured lipid carrier loaded with alpha-mangostin and clove oil (NLC-AMCO) against MDR oral bacteria. Forty-nine bacterial strains were isolated and characterized from thirty dogs diagnosed with clinical periodontitis. Antibacterial activity was assessed using standard phenotypic assays, including disc diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and total plate count (TPC), while whole genome sequencing (WGS) was applied to identify resistance gene profiles. NLC-AMCO demonstrated superior antimicrobial efficacy compared to alpha-mangostin and clove oil (AMCO) and commonly used antibiotics (amoxicillin, clindamycin, doxycycline, and metronidazole), exhibiting broader inhibition zones (up to 24-30 mm) and rapid bactericidal activity within 30 min. Time-dependent improvements in MIC and MBC values confirmed the sustained-release capability of the NLC-AMCO. At 48 h, MICs were reduced by half for key MDR isolates, including Escherichia coli_CU1 (31.25 to 15.62mg/mL), Morganella morganii_CU1 (15.62 to 7.8mg/mL), and Acinetobacter baumannii (3.9 to 1.95mg/mL), with comparable decreases in MBC values. WGS analysis revealed extensive resistomes, particularly in Pseudomonas aeruginosa and E. coli, carrying genes resistant to fluoroquinolones and last-resort agents such as colistin. These findings highlight the potential of NLC-AMCO as a plant-based nano-formulation for improving veterinary dental care in dogs with MDR infections and support its relevance for future antimicrobial-stewardship strategies in companion-animal medicine.

To Cite This Article: Sawatphakdee G, Payungporn S, Chanchaem P, Yostawonkul J, Kamble MT, Tabtieang SP, Nowwarote N, and Pirarat N, 2026. Genetic characterization of multidrug-resistant bacteria and antibacterial activity of alpha-mangostin and clove oil nanostructured lipid carriers in canine periodontitis. Pak Vet J, 46(3): 681-690. http://dx.doi.org/10.29261/pakvetj/2026.057

Abstract

ISSN 0253-8318 (Print)ISSN 2074-7764 (Online)

ISSN 0253-8318 (Print)
ISSN 2074-7764 (Online)