[Br. ovis sensitivity to antibiotics]

Area of Science:

• Veterinary Microbiology
• Antimicrobial Resistance
• Bacterial Pathogenesis

Background:

• Brucella ovis is a significant pathogen in animal health.
• Understanding antimicrobial susceptibility is crucial for effective treatment strategies.
• Geographical origin does not appear to influence the sensitivity of Br. ovis to key antibiotics.

Purpose of the Study:

• To determine the antibiotic sensitivity profile of Brucella ovis strains.
• To compare the antimicrobial resistance between different variants of Br. ovis.
• To identify effective bactericidal concentrations for key antibiotics against Br. ovis.

Main Methods:

• Bactericidal concentration testing of various antibiotics against Br. ovis cultures.
• Comparative analysis of antibiotic sensitivity between S-subcultures and R-variants of Br. ovis.
• Determination of minimum bactericidal concentrations (MBCs) for tetracycline and streptomycin.

Main Results:

• High sensitivity of Br. ovis to tetracycline (0.02–0.04 γ/ml) and streptomycin (0.1–0.4 γ/ml) was observed.
• Morphocycline, kanamycin, benzyl-penicillin, lincomycin, and monomycin showed less pronounced bactericidal effects.
• Polymyxin M demonstrated no bactericidal activity even at high concentrations (200 γ/ml).
• Genetically related S-subcultures of Br. ovis were found to be more resistant to antibiotics than their initial R-variants.

Conclusions:

• Tetracycline and streptomycin are highly effective against most Br. ovis strains.
• Antibiotic resistance patterns differ between S-subcultures and R-variants, with S-forms being more resistant.
• Further research into the mechanisms of resistance in S-subcultures may inform treatment approaches.