„Staphylococcus, segregated from mastitic milk of cows, resistance to antibiotics“

Work consist of 47 sheets, presented in 9 tables, 12 pictures, 1 scheme of the work and 65 literary sources. Objective of work – To investigate Staphylococcus aureus and coagulase negatyve Staphylococcus (CNS), segregated from milk, resistance to antibiotics and estimate genes determinated resistance to antibiotics. Work was prepared in Microbiology and virology institute of the Veterinary academy, Lithuanian University of Health Science. From 110 mastitis sicked cows, were determinated big variety of staphylococcus species: S. aureus – 52 (47,3 %), and coagulase negative 58 (52,7 %) staphylococcus. In between mostly were determinated S. chromogenes - 37,5 % cases and S. warneri - 25 % cases. Level of resistance to antibiotics similar between SPP and CNS specieses. 84,5 % of CNS and all S. aureus specieses were resistant to penicilin. Between staphilococcus dominated specieses, which were resistant to tetracykline, erythromycin, gentamicin too and susceptible to ciprofloxacin and sulfonamid with trimetoprim combination (SXT). Results of quantitative and qualitative investigations of resistance to antibiotics correlated. Quantitative investigation of resistance to antimicrobial substances evidenced more resistant species. S. aureus 100 % and 75 % CNS specieses determinated betalactamas produced and their exposure coding blaZ gene. For major specieses detected mecA gene. Nine S. aureus and five CNS specieses were determinated resistanted to methicillin