124 Original article Extract nature influences the effects of Melissa officinalis L. on the milk microbiome in cows with subclinical mastitis R. Giupana, Niculae Mihaela, Pall Emoke, V. Negrutiu, Silvana Popescu, A. Vasiu, Puscasu Raluca, Sandru Carmen Dana and Spinu Marina Department of Clinical Sciences-Infectious Diseases, University of Agricultural Sciences and Veterinary Medicine, Str. Manastur No.3-5, Cluj-Napoca, Romania Received September 12, 2018: Revised October 28, 2018: Accepted November 4, 2018: Published online December 30, 2018 Abstract Mastitis in dairy cows represents one of the most economically impacting pathology, the managment costs being augmented by difficulties in diagnosing the subclinical form of the disease. The biased and non-discriminatory use of antibiotics led to their lesser efficacy, therefore therapeutic alternatives are looked for. In this study, the influence of the extraction solvent on the antimicrobial effectiveness of Melissa officinalis L. was assessed on subclinical mastitis microbiome. Milk and blood samples were harvested from dairy cows at the peak of the lactation. N/L ratios from the blood (Panoptic stain) were calculated as indicators of the degree of stress/immune suppression in subclinical disease. The microbiome components were identified by use of classical bacteriological methods and cultivated against M. officinalis alcoholic extract and essential oil (Kirby-Bauer method). Minitab 16.0 was used for the statistical interpretation of the data while the significance of the differences between the groups was interpreted by Student’s t test. N/L ratios indicated significantly increased stress ( p < 0.01) in subclinically affected animals (1.24 ± 0.69) when compared to healthy ones (0.56 ± 0.12). In bacteria from mastitic milk, M. officinalis alcoholic extract was less effective than the essential oil (inhibition zone of 11.3 ± 3.6 mm versus 12.3 ± 4.3 mm), but comparable to amoxicillin, amoxicillin/clavulanic acid and higher than cefoperazone (total resistance). Similarly, in healthy milk isolates, the effects were more pronounced for the essential oil than for the tincture (18.67 ± 7.0 mm versus 13.0 ± 8.2 mm) and higher than in cefoperazone (15.67 ± 3.2 mm). The results suggested that the therapeutic use of M. officinalis essential oil rather than the alcoholic extract could prove to be efficient against mastitic milk bacteriome, depending on the bacteria genus more than on the extract type. Key words: Dairy cows, subclinical mastitis, Melissa officinalis L., microbiome, therapy Copyright @ 2018 Ukaaz Publications. All rights reserved. Email: ukaaz@yahoo.com; Website: www.ukaazpublications.com 1. Introduction Considered to be a multifactorial disease, mastitis exerts a high economic impact due to increased production costs, health related costs and control and preventive measures to be implemented (Kvapilík et al., 2015). Difficulties to diagnose subclinical forms of the disease, further complicate the control of the disease (Asfaw and Negash, 2017). Staphylococcus spp. stands for the most prevalent etiological agent of this complex infection in dairy cows, but also expresses an important zoonotic potential, thus posing a health risk for contacts and consumers. Furthermore, the etiology of the disease could be complicated by the presence of environmental and also gut origin microflora, aquired by the immediate contact of Annals of Phytomedicine 7(2): 124-128, 2018 DOI: 10.21276/ap.2018.7.2.19; Print ISSN : 2278-9839 and Online ISSN : 2393-9885 7(2):124-128 (2018) Ann. Phytomed., Author for correspondence: Dr. Sandru Carmen Dana Assistant Professor, Department of Clinical Sciences-Infectious Diseases, University of Agricultural Sciences and Veterinary Medicine, Str. Manastur No.3-5, Cluj-Napoca, Romania E-mail: sandranac@gmail.com Tel.: +40-264596384/173 infected animals with their habitat (floors, bedding, fodder, caretakers, etc.) (Machado et al., 2008). The interaction is reciprocal, the animals infected with multiple microbial strains shedding those to the environment, further perpetuating the disease to naive incoming dairy animals and increasing its prevalence. The management of this pathology is mainly based on the extensive antibiotic use (Pieterse and Todorov, 2010), which has triggered the development of high levels of antimicrobial resistance (Motlagh et al., 2013). Lesser efficacy of antibiotics used to treat both clinical and subclinical mastitis due to their irrational and extensive involvement in therapeutic schemes, led to numerous researches on finding efficient alternatives, such asprobiotics, phytobiotics and plant essential oils (De and Mukherjee, 2013). Millenia of phytomedical practice with positive results, high physical and biological availability, low costs, lack of side effects in most of them, regional and local traditions were some of the reasons that supported the development of scientific research in the area of medicinal plant uses in both human and veterinary medicine (Biradar, 2015). According to WHO, almost 80% of the