Antibiotic treatment of Streptococcus bovis infections in pigeons.

The antibiotic susceptibility pattern of 5. bovis strains isolated from pigeons was studied. In vitro, S. bovis strains were sensitive to penicillins, macrolides, lincomycin, tetracyclines, chloramphenicol and nitrofurans. However, the prevalence of acquired resistance against tetracyclines was approximately 40%. Sulphonamides and trimethoprim had little in vitro activity against 5. bovis while activity of the quinolone enrofloxacin and the aminoglycoside antibiotics, neomycin and gentamicin, were in or near to the intermediate range. The comparative efficacy of 5 antimicrobials administered via the drinking water for the treatment of experimental S. bovis infection in pigeons was also tested. Morbidity after intravenous inoculation of S. bovis in groups of pigeons treated with ampicillin, erythromycin, doxycycline, enrofloxacin and trimethoprim was 20%, 30%, 20%, 70% and 90%, respectively. Morbidity in an untreated control group was 90%.