Study Synergistic Interactions between Antibiotics and Ascorbic Acid against Pseudomonas Aeruginosa Isolated Bovine Mastitis

  • Khairi Jameel Al-Ruaby, Mohammed Ibrahim Mohammed, Isa S. Touhali


The present study was carried out to isolate Pseudomonas aeruginosa from cattle (bovine) milk with mastitis and shed light upon some materials that worked in increasing antibiotic activity against isolated bacteria. Two hundred and twenty bovine milk samples were collected randomly from different local cow farms at districts of Wasit governorate, Iraq. During the period from the mid of October 2021 to the end-February 2022.37(16.8%) P. aeruginosa isolates were obtained using bacterial culture method and further identified by Analytical Profile Index (API-20E) and Vitek 2 system. Antibiotic susceptibility test was conducted for bacterial isolates , tested by disc diffusion method using (12) antibiotics and the results showed a different percentage of resistance to each antibiotic as (Gentamycin, amikacin, ampicillin, bacitracin, Ciprofloxacin, Norfloxacin, chloramphenicol, erythromycin, tetracycline, streptomycin, tobramycin, Trimethoprim_sulfamethoxazole). The results revealed that Ciprofloxacin was the most effective antibiotic against bacterial isolates followed by amikacin and then by Norfloxacin, and the isolates are completely resistant to both erythromycin and tetracycline. Twelve isolates were selected to detect the effect of ascorbic acid when was combined with antibiotics and tested by using disk diffusion assay. Various concentrations of the ascorbic acid were used, starting from (1 to 22.2 mg). The results showed that there is a synergistic interaction between vitamin C and most of the antibiotics, Also, the synergistic effect increases with increasing concentration of the vitamin. The antibiotic chloramphenicol had the greatest effect, as the area of inhibition increased in 11 out of 12 isolates. Also, the tests showed that ascorbic acid had an antagonistic effect on some antibiotics such as norfloxacin and tobramycin, where the inhibition area decreased in 9 and 8 isolates, respectively.

Sensitivity test by using discs diffusion assay.
How to Cite
Isa S. Touhali, K. J. A.-R. M. I. M. (2022). Study Synergistic Interactions between Antibiotics and Ascorbic Acid against Pseudomonas Aeruginosa Isolated Bovine Mastitis. Revista Electronica De Veterinaria, 119 - 129. Retrieved from