Green synthesis of zinc oxide nanoparticles using origanum minutiflorum plant extract and their antibacterial, antioxidant activities on staphylococcus aureus isolated from subclinical mastitis

Milk is the essential protein source for all living things. Mastitis is a disease that affects the mammary tissue of dairy animals. Changes in milk composition together with treatment costs lead to loss of quality in milk. The use of antibiotics is inevitable in the fight against mastitis. However, resistance to mastitis agents has become an important problem of the dairy industry. Clinical mastitis is the most common disease affecting dairy animals worldwide. Clinical mastitis has adverse effects such as loss of milk quantity, treatment costs, veterinary services, and death of dairy animals. Subclinical mastitis occurs in the breast without clinical manifestations. Staphylococcus aureus, Escherichia coli, Streptococcus spp. are the major pathogens of subclinical mastitis. S. aureus is a pathogenic species for humans and animals and is considered one of the most important causes of foodborne intoxications and mastitis in the world. New strategies are needed to combat bacteria due to resistance to antibiotics. A total of 350 dairy animals belonging to Burdur Center and its districts were screened with the California Mastitis Test. Isolation and identification of S. aureus were performed from the obtained milk samples with subclinical mastitis. The effect of Origanum minutiflorum and ecologically synthesized zinc oxide nanoparticle (ZnO NP) for inactivation of the isolates was investigated. As a result of the study, ZnO NP synthesis was synthesized and characterized using Origanum minutiflorum. With the evaluation performed for subclinical mastitis, 41.14% of the animals screened were positive. As a result of the identification tests performed for the isolates obtained, 34 (14.70%) isolates were identified as S. aureus. Twenty nine (20.13%) of the animals positive for subclinical mastitis were evaluated as positive for S. aureus. Isolates were found to be resistant to various antibiotics. Origanum minutiflorum derived ZnO NP showed antimicrobial effect on all isolates. The effect value at which the antimicrobial effect occurred was between 62.5 µg/ml and 2000 µg/ml. With the antimicrobial effect of Origanum minutiflorum -derived ZnO NP, which was synthesized, inactivation was detected with different MIC values on all isolates, and a critical product synthesis was achieved for alternative antibiotic substances. Due to the high level of antibiotic resistance in isolates, more studies on antibiotic alternatives should be planned.