Antimicrobial Effect of Curcuma longa and Zingiber officinale on Bacteria Isolated from Domestic Dogs in Port Harcourt, Nigeria

Background: Antimicrobial resistance in canine microbiota, influenced by antibiotic use in veterinary medicine and environmental exposure, poses a public health risk. Medicinal plants offer a potential multi-targeted approach to addressing antimicrobial resistance. Materials and Methods: This study assessed the antimicrobial effects of Curcuma longa and Zingiber officinale on bacterial isolates from domestic dogs in Port Harcourt, Nigeria. Sterile swabs were used to collect samples from the mouth, skin, ear and anus of domestic dogs. Samples were cultured on nutrient agar, mannitol salt agar, eosin methylene blue agar and MacConkey agar. Bacterial isolates were identified by colonial morphology, Gram staining and biochemical tests. Antibiotic susceptibility was assessed using the Kirby–Bauer disc diffusion method. The antimicrobial effects of the plant extracts were evaluated using the disc diffusion method. Results: A total of 14 bacterial isolates belonging to 10 genera were identified: Klebsiella spp., Proteus spp., Enterobacter spp., Escherichia spp., Kluyvera spp., Providencia spp., Salmonella spp., Bacillus spp., Staphylococcus spp. and Micrococcus spp. Antibiotic susceptibility testing showed that Salmonella spp. isolates exhibited 100% resistance to Ceporex, ceftriaxone, streptomycin, cefuroxime, Augmentin and ceftazidime, while other isolates showed varying degrees of resistance and susceptibility to the antibiotics tested. In the plant-extract susceptibility test, 75% of the tested isolates were inhibited by ethanolic turmeric extracts, compared with 50% by ethanolic ginger extracts. Conclusion: Domestic dogs harbour microorganisms that display resistance to conventional antibiotics and susceptibility to ethanolic extracts of turmeric and ginger. These plants could serve as additives for the production of dog feed or dog-cleaning agents.