The inoculated broth was incubated for 4 h to approximately 106 CFU/ml at McFarland 0.5 % level of turbidity (CLSI 2007). With this culture, a bacterial lawn was prepared on Mueller–Hinton agar (Oxoid, UK). Antimicrobials against (Oxoid, UK) including chloramphenicol (C 30 µg), neomycin (N 30 µg), oxytetracycline (OT 30 µg), polymyxin-B (PB 300 IU) and trimethoprim-sulfamethoxazole (SXT 1.25/23.75/µg) were used for test. Result was interpreted using the diameter of zone of bacterial growth inhibition surrounding the disc (CLSI 2007).