Identification the Effect of Some Antibiotics on the Activities of Brucella melitensis that Isolated from Patients in Baghdad

Brucellosis constitutes a major health problem around the world, especially in developing countries. The sensitivity pattern of the Brucella isolates encountered in the most countries, numerous studies were indicated the sensitivity of Brucella melitensis to some antibiotics and resistance to another. The aim of this study to evaluated, in vitro, the effect of single and combination of some antibiotics on the activities of Brucella melitensis.             This study included collection of (100) clinical sample of blood from different hospital in Baghdad. Six isolates of Brucella melitensis were identified and determine according to their biotypes. The susceptibility to different antibiotics was evaluated by disk diffusion method and MICs for some antibiotics used for brucellosis treatment were applied. Some antibiotics combination affect at concentrations of sub MIC on the growth of Brucella melitensis.             Results showed that isolates of Brucella melitensi were sensitive completely to gentamycin, kanamycin and naldixic acid while it’s resistant to lincomycin, rifampicin, ciprofloxacin, Levofloxacin and doxycyline.             The MIC to doxycycline and rifampicin were (40 and 5) μg/ml. respectively. There was an important effect on bacterial growth when the following antibiotics were mixed as (doxycyline+ rifampicin). The doxycycline changed the colonies from growth phase )pathogen phase( to intermediate phase while the rifampicin had no effect on colonies. The mixed of doxycycline with rifampicin have effect that change the pathogen phase to non pathogen phase (no growth phase).             By this study, we can conclude a combination of antibiotics should be used to treat Brucellosis, tetracyclines, quinolones, trimethoprim/sulfamethoxazole, rifampicin, and streptomycin are commonly used preparations for this treatment