In vitro Antibacterial Efficacy of 7 Plant Extracts on Staphylococcus aureus Isolated From Equine Skin Lesions

Background: Staphylococcus aureus is a prevalent opportunistic pathogen which is increasingly associated with various equine dermatological afflictions. The burgeoning issue of antibacterial resistance against this bacterium necessitates novel therapeutic approaches. This study, executed from May to November (2022) at the National Research Centre on Equine, Equine Production Centre, Bikaner, aimed to isolate and identify S. aureus from equine dermal lesions and to assess the in vitro efficacy of both organic (methanolic, aqueousand ethanolic) and inorganic (chloroform and petroleum ether) phytoextracts from Calotropis gigentean, Capparis decidua, Leptadenia pyrotechnica, Aerva javanica, Azadirachta indica, Aloe vera and Eucalyptus camaldulensis. Method: The study utilised agar well diffusion and broth dilution techniques to assess the antimicrobial efficacy of these extracts against S. aureus. Result: Microscopic analysis of gram-stained smears from cultures, alongside a suite of biochemical assays and polymerase chain reaction (PCR), corroborated the presence of S. aureus. The antimicrobial screening disclosed that both organic and inorganic extracts of E. camaldulensis manifested the most pronounced antibacterial activity, exhibiting zones of inhibition ranging from 15 mm to 21 mmand minimum inhibitory concentrations between 1.56 to 3.13 mg/mL. Furthermore, extracts from A. indica (chloroform, methanolicand ethanolic) and A. vera (methanolic and ethanolic) also demonstrated antibacterial effectiveness against this pathogen, with inhibition zones extending from 15 mm to 17.33 mm (MIC: 3.13 to 25 mg/mL) and 9 mm to 12 mm (MIC: 12.5 to 25 mg/mL), respectively. Moreover, the outcomes of this investigation substantiate the antibacterial capabilities of E. camaldulensis, A. indica and A. vera against dermatological pathogens, advocating their inclusion in topical antibacterial formulations as a strategic countermeasure to the escalating challenge of drug resistance.