Vancomycin

Antimicrobial susceptibility test was confirmed by the ANSES laboratory using the disk diffusion method and interpreted according to the guidelines of the Antibiogram Committee of the French Society for Microbiology³. S. aureus ATCC 25923 was used as quality control. In addition, 16 antibiotics of veterinary and/or human interest were tested: penicillin G, cefoxitin, cefovecine, kanamycin, gentamicin, tobramycin, tetracycline, erythromycin, spiramycin, lincomycin, chloramphenicol, florfenicol, fusidic acid, enrofloxacin, vancomycin, teicoplanin (Mast Diagnostics, Amiens, France).

Standard discs of 17 antibiotics were obtained from Mast Diagnostics (Merseyside, Liverpool, UK) to be used in this assay; amikacin (30 µg), ampicillin (10 µg), augmentin (30 µg), aztreonam (30 µg), cefoxitin (30 µg), cefepime (30 µg), ceftazidime (30 µg), cephalothin (30 µg), chloramphenicol (30 µg), ciprofloxacin (5 µg), cotrimoxazole (25 µg), fucidic acid (10 µg), gentamicin (10 µg), imipenem (10 µg), oxacillin (1 µg), piperacillin (100 µg), and vancomycin (30 µg).
Antimicrobial activity of four cLfs isolated from milk of four different breeds of Saudi camels (cLf1, cLf2, cLf3, and cLf4), bLf, hLf, and the standard antibiotics against S. typhimurium and S. sonnei was tested by agar disc-diffusion technique. Plates of Mueller-Hinton (MH) agar were overlaid with 2 × 10⁶ CFU/ml of Salmonella typhimurium LT2 and Shigella sonnei. Wells of about 5 mm diameter were made on inoculated plates then different concentrations of lactoferrins (0.00, 0.125, 0.250, 0.50, 0.750, 1, 1.5, 2, 2.5, and 3 mg/ml) were added, and left to diffuse in agar at 4 °C for 2 h before plates finally incubated overnight at 37 °C. The diameters of clear inhibition zones were measured in millimeters. Antibacterial effects of different lactoferrins on growth of S. typhimurium and S. sonnei after 1, 3, 6, 12, and 24 h of incubation at 37 °C were monitored spectrophotometrically (measuring OD at 620 nm).