In vitro antimicrobial activity of sulfonamides against some porcine pathogens
Mengelers, M.J.; van Klingeren, B.; van Miert, A.S.
American Journal of Veterinary Research 50(7): 1022-1028
1989
ISSN/ISBN: 0002-9645 PMID: 2774319 Document Number: 337169
The minimal inhibitory concentrations (MIC) of sulfonamides were determined against Bordetella bronchiseptica (n = 10), Pasteurella multocida (n = 10), Haemophilus pleuropneumoniae (n = 20), and Streptococcus suis (n = 10) strains isolated from pigs with atrophic rhinitis, pneumonia, or meningitis. Sulfonamides tested in an agar dilution method were sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfamethazine, sulfadoxine, sulfisoxazole, sulfamerazine, sulfamethoxazole, sulfamethoxypyridazine, sulfanilamide, sulfatroxazole, and sulfisomidine. Results indicated that monotherapy of S suis infections with sulfonamides should not be encouraged because the MIC50 of all sulfonamides investigated was greater than 32 micrograms/ml. The MIC50 of the sulfonamides against B bronchiseptica ranged from 0.5 to 8 micrograms/ml, against P multocida from 2 to 32 micrograms/ml, and against H pleuropneumoniae from 8 to 64 micrograms/ml. The MIC50 of sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfamerazine, and sulfamethoxazole for the gram-negative bacteria did not exceed 16 micrograms/ml. Among these compounds, sulfamethoxazole had the highest activity. The frequently prescribed sulfamethazine had an overall low antimicrobial activity.