Antimicrobial Activity of Photosynthetic Microorganisms Biomass Extract against Bacterial Isolates Causing Mastitis

Photosynthetic Microorganisms are organisms rich in bioactive compounds, which are used as food supplement and have various pharmacological properties, such as antibacterial potential. Mastitis is a pathology featured to inflammation of the udder, caused by fungi, bacteria or viruses. Mastitis treatment is by antibiotics intra-mammary infusion, and the indiscriminate use can cause resistance from the bacteria, hindering the therapy of this disease. The aim of this work was evaluated antimicrobial activity of Chlorella vulgaris, Arthrospira platensis and Dunaliella tertiolecta extracts against isolates causing goat (19 strains) and bovine (16 strains) mastitis, using broth microdilution method. The extracts were obtained using Sodium Acetate Buffer, 1 M, pH 5.5 (SAB), Water (W) and Chloroform-methanol (CM). The three microalgal extracts showed interesting antimicrobial properties, the lowest MIC value was of 25 μg/mL for C. vulgaris (CM extract) and Dunaliella tertiolecta (water extract) against Staphylococcus sp. of bovine mastitis and 25 μg/mL using SAB and water extracts from A. platensis, which mostly inhibited the growth of isolated Staphylococcus sp. of goat mastitis. These results could mean a breakthrough in the veterinary pharmaceutical industry and consequently a direct and effective applicability in veterinary medicine, reducing damage caused by mastitis in bovine and goat herds.