Abstract

Mastitis is an important infectious disease of cattle and Pseudomonas aeruginosa (P. aeruginosa) bacteria standout amongst those fundamental causative agents. The present study was intended to assess P. aeruginosa activity isolated from mastitic cattle milk samples in a veterinary hospital. It also was assessed some free radicals and immunological parameters in the milk and serum samples. Control samples were taken from apparently healthy cows, negative California Mastitis test. The results cleared that positive P. aeruginosa isolates were 34 of 100 milk samples. In vitro antibiotic sensitivity test indicated that 79.4%, 70.5% and 58.82% of the isolates completely resisted cefotaxime, penicillin and amikacin respectively. Also, the resistance to meropenem was 11.76% and 8.8% for carbapenem resistant isolate which completely resisted other classes of β-lactams. While enrofloxacin and gentamicin sensitivity reached to 76.47% and 73.5% respectively. The technique of the P.C.R was done for detection of MexR gene (in isolates resisted to more than three antibiotics) and Vim gene (in carbapenem resistant isolates). The biochemical results investigated that the nitric oxide and Mmalondialdehyde antioxidant levels were increased significantly while the cholesterol was decreased significantly in both serum and milk samples. Meanwhile, catalase and lysozyme were changed between groups and total protein and globulin had increased significantly in milk samples only. In conclusion, P. aeruginosa isolates including MexR and blaVim genes showed considerable percent of resistance to carbabenem group and other classes of β-lactam. In addition, the estimated biochemical and immunological parameters were affected in that case of mastitis in cattle. The results may encourage studies which are concerned with antioxidants treatment for mastitis in cattle. It may be a key for decreasing body resistance to antibiotics.