Identification of bacterial species in milk by MALDI-TOF and assessment

Abstract

This study aimed to identify bacterial pathogens in milk samples from dairy cows with sub -clinical and clinical mastitis as well as to assess the concentrations of oxidant-antioxidant param-eters [malondialdehyde (MDA), reduced glutathione (GSH), and total GSH levels] in both blood and milk samples. From a total of 200 dairy cows in 8 farms, 800 quarter milk samples obtained from each udder were tested in the laboratory for the presence of udder pathogens. Cultivated bacteria causing intramammary infection from milk samples were identified by Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF). In addition, from tested animals 60 cows were selected includ??ng 20 healthy cows that were CMT negative, 20 cows with subclini-cal mastitis (SM), and 20 cows with clinical mastitis (CM) for detection of MDA, GSH, and total GSH levels in blood and milk samples. Three hundred and eighty (47.5%; 380/800), 300 (37.5%; 300/800), and 120 (15%; 120/800) of milk samples, respectively were CMT positive or SM and CM, and those positives were cows from different farms. We observed that 87.4% (332/380), 25.3% (76/300), and 34.2% (41/120) of cows with CMT positive, CMT negative, and CM had bacterial growth. The most predominantly identified bacteria were Staphylococcus chromogenes (18.7%) obtained mainly from SM and Staphylococcus aureus (16.7%) as the most frequent cau-se of CM. According to our results, dairy cows with CM had the highest MDA levels, the lowest GSH, and total GSH levels in both blood and milk samples however, high MDA levels and low GSH levels in milk samples with SM were observed. Based on our results, lipid oxidant MDA and antioxidant GSH could be excellent biomarkers of cow???s milk for developing inflammation of the mammary gland. In addition, there was no link between nutrition and MDA and GSH levels.

C1 [Ozbey, G.; Cambay, Z.; Aytekin, O.; Ozcelik, M.] Firat Univ, Vocat Sch Hlth Serv, Dept Med Serv & Tech, Rectorate Campus, TR-23119 Elazig, Turkey.

[Yilmaz, S.] Firat Univ, Dept Biochem, Fac Vet Med, Rectorate Campus, TR-23119 Elazig, Turkey.

[Zigo, F.] Univ Vet Med & Pharm Kosice, Dept Nutr & Anim Husb, Komenskeho 73, Kosice 04001, Slovakia.

[Otlu, B.] Inonu Univ, Dept Med Microbiol, Fac Med, Main Campus, TR-44280 Malatya, Turkey.